This document outlines the cells of the immune system, including their formation, types, and roles. It discusses:
1) The two major lineages that blood cells originate from in the bone marrow - myeloid and lymphoid.
2) The types of leucocytes (white blood cells), which include granulocytes like neutrophils, eosinophils and basophils, and agranulocytes.
3) The cells of the innate immune system that provide first line defense, such as neutrophils, macrophages, dendritic cells and natural killer cells, and their mechanisms of phagocytosis and intracellular killing.
The document outlines the objectives and key concepts of innate and adaptive immunity. It discusses:
- The principal cells and tissues of the immune system, including lymphocytes, macrophages, neutrophils, and dendritic cells.
- The differences between innate and adaptive immunity, where innate immunity provides immediate response and adaptive immunity has immunological memory and is antigen-specific.
- How innate immunity involves epithelial barriers, phagocytes, natural killer cells, and plasma proteins while adaptive immunity involves lymphocytes and humoral or cell-mediated responses.
- How lymphocytes recognize antigens through membrane-bound antibodies on B cells or T cell receptors that recognize antigen peptides bound to MHC molecules.
T-cells are a type of white blood cell that play a major role in the immune system by fighting infection. There are different types of T-cells that act in various ways to identify and destroy pathogens. T-cells mature in the thymus gland, where they develop receptors called TCRs that allow them to recognize antigens bound to MHC molecules on other cells. The MHC presents antigen fragments to T-cells to trigger an immune response against invading microbes.
2 antigens, immunogens, epitopes, and haptenstaha244ali
This document discusses key concepts in immunology including antigens, immunogens, epitopes, haptens, innate immunity, and adaptive immunity. It defines antigens as molecules recognized by the immune system and immunogens as antigens that elicit an immune response. Epitopes are the smallest part of an antigen recognized by B and T cell receptors. Haptens are small molecules that require a carrier to induce an immune response. Innate immunity provides the first line of defense using soluble proteins and cells like phagocytes. Adaptive immunity develops over time through T and B cell responses and produces immunological memory.
This document discusses the different types of immune cells. It describes lymphocytes including B cells, T cells, and natural killer cells. It also discusses mononuclear phagocytes such as monocytes and macrophages. Granulocytic cells including neutrophils, eosinophils, and basophils are also covered. The document concludes by briefly mentioning mast cells, dendritic cells, and follicular dendritic cells.
This document discusses tumor immunology and cancer immunotherapy. It provides information on tumor antigens, how tumors stimulate an immune response, and mechanisms tumors use to evade the immune system. The document also outlines several approaches to cancer immunotherapy, including monoclonal antibodies, cytokines, and adoptive cell therapy. A brief history of cancer immunotherapy is given, noting early experiments in the 1890s using bacterial toxins to treat tumors and discoveries in the 1960s about antibody receptors and T cells recognizing cancer cells.
This document provides an overview of immunology and the immune system. It discusses the history of immunology including the discoveries of Metchnikoff, Behring, and Fleming. It also describes the innate and adaptive immune systems. The main cells of the immune system are B cells, T cells (including T helper cells, T cytotoxic cells, and T suppressor cells), and natural killer cells. Primary lymphoid organs that support immune cell development include the bone marrow and thymus. Secondary lymphoid organs where immune responses occur include lymph nodes, spleen, Peyer's patches, and mucosa-associated lymphoid tissue.
B cells are lymphocytes that play a key role in humoral immunity by producing antibodies. B cell development occurs in the bone marrow, progressing from pro-B cells to immature B cells that express IgM, and then to mature B cells that express IgM and IgD. Activation of B cells leads to proliferation and differentiation into plasma cells in secondary lymphoid organs. Defects in B cell development or function can cause immunodeficiencies characterized by poor antibody production and recurrent bacterial infections. Some examples of B cell immunodeficiencies include X-linked agammaglobulinemia caused by mutations in BTK, IgA deficiency, and common variable immunodeficiency.
This document summarizes the key stages in B-lymphocyte maturation, generation, and activation. It discusses how B cells develop from progenitor cells in the bone marrow, where they undergo antigen-independent maturation including immunoglobulin gene rearrangement and positive and negative selection to remove self-reactive cells. Mature B cells then leave the bone marrow equipped with B cell receptors. The document also describes how B cells are activated upon binding of antigen to their receptor, requiring co-stimulation by T helper cells to initiate the antibody response.
The document outlines the objectives and key concepts of innate and adaptive immunity. It discusses:
- The principal cells and tissues of the immune system, including lymphocytes, macrophages, neutrophils, and dendritic cells.
- The differences between innate and adaptive immunity, where innate immunity provides immediate response and adaptive immunity has immunological memory and is antigen-specific.
- How innate immunity involves epithelial barriers, phagocytes, natural killer cells, and plasma proteins while adaptive immunity involves lymphocytes and humoral or cell-mediated responses.
- How lymphocytes recognize antigens through membrane-bound antibodies on B cells or T cell receptors that recognize antigen peptides bound to MHC molecules.
T-cells are a type of white blood cell that play a major role in the immune system by fighting infection. There are different types of T-cells that act in various ways to identify and destroy pathogens. T-cells mature in the thymus gland, where they develop receptors called TCRs that allow them to recognize antigens bound to MHC molecules on other cells. The MHC presents antigen fragments to T-cells to trigger an immune response against invading microbes.
2 antigens, immunogens, epitopes, and haptenstaha244ali
This document discusses key concepts in immunology including antigens, immunogens, epitopes, haptens, innate immunity, and adaptive immunity. It defines antigens as molecules recognized by the immune system and immunogens as antigens that elicit an immune response. Epitopes are the smallest part of an antigen recognized by B and T cell receptors. Haptens are small molecules that require a carrier to induce an immune response. Innate immunity provides the first line of defense using soluble proteins and cells like phagocytes. Adaptive immunity develops over time through T and B cell responses and produces immunological memory.
This document discusses the different types of immune cells. It describes lymphocytes including B cells, T cells, and natural killer cells. It also discusses mononuclear phagocytes such as monocytes and macrophages. Granulocytic cells including neutrophils, eosinophils, and basophils are also covered. The document concludes by briefly mentioning mast cells, dendritic cells, and follicular dendritic cells.
This document discusses tumor immunology and cancer immunotherapy. It provides information on tumor antigens, how tumors stimulate an immune response, and mechanisms tumors use to evade the immune system. The document also outlines several approaches to cancer immunotherapy, including monoclonal antibodies, cytokines, and adoptive cell therapy. A brief history of cancer immunotherapy is given, noting early experiments in the 1890s using bacterial toxins to treat tumors and discoveries in the 1960s about antibody receptors and T cells recognizing cancer cells.
This document provides an overview of immunology and the immune system. It discusses the history of immunology including the discoveries of Metchnikoff, Behring, and Fleming. It also describes the innate and adaptive immune systems. The main cells of the immune system are B cells, T cells (including T helper cells, T cytotoxic cells, and T suppressor cells), and natural killer cells. Primary lymphoid organs that support immune cell development include the bone marrow and thymus. Secondary lymphoid organs where immune responses occur include lymph nodes, spleen, Peyer's patches, and mucosa-associated lymphoid tissue.
B cells are lymphocytes that play a key role in humoral immunity by producing antibodies. B cell development occurs in the bone marrow, progressing from pro-B cells to immature B cells that express IgM, and then to mature B cells that express IgM and IgD. Activation of B cells leads to proliferation and differentiation into plasma cells in secondary lymphoid organs. Defects in B cell development or function can cause immunodeficiencies characterized by poor antibody production and recurrent bacterial infections. Some examples of B cell immunodeficiencies include X-linked agammaglobulinemia caused by mutations in BTK, IgA deficiency, and common variable immunodeficiency.
This document summarizes the key stages in B-lymphocyte maturation, generation, and activation. It discusses how B cells develop from progenitor cells in the bone marrow, where they undergo antigen-independent maturation including immunoglobulin gene rearrangement and positive and negative selection to remove self-reactive cells. Mature B cells then leave the bone marrow equipped with B cell receptors. The document also describes how B cells are activated upon binding of antigen to their receptor, requiring co-stimulation by T helper cells to initiate the antibody response.
ORGANS OF IMMUNE SYSTEM PRIMARY AND SECONDARY LYMPHOID ORGANSSruthy Chandran
The document summarizes the primary and secondary lymphoid organs of the immune system. The primary lymphoid organs, such as the bone marrow and thymus, are where lymphocytes mature and develop. The secondary lymphoid organs, including lymph nodes, spleen, and mucosa-associated lymphoid tissue (MALT), trap antigens and activate lymphocytes. In these organs, B cells are activated, differentiate into plasma cells, and secrete antibodies to help fight infection.
introduction of adaptive immunity. classification of adaptive immunity, factor affecting it and mechanism of adaptive immunity comparison between adaptive immunity and innate immunity. characteristic of adaptive immunity . cell mediated immune responses immunoglobulins
types of immunoglobulins. functions of immunoglobulins, hypersensitivity reactions
This document summarizes antigen processing and presentation. It discusses that antigen presenting cells such as macrophages, dendritic cells, and B cells express class II MHC molecules and provide co-stimulatory signals to activate T helper cells. These cells internalize antigens through phagocytosis or endocytosis, degrade them into peptides, and present the peptides bound to class II MHC on their surface. The document also describes the major histocompatibility complex and the roles of class I and class II MHC molecules in antigen presentation to T cells. It outlines the exogenous and endogenous antigen processing pathways, how exogenous antigens are presented by class II MHC and endogenous antigens by class I MHC.
The document provides an overview of the immune system, including its main cells and functions. It discusses how immune cells such as lymphocytes (B cells, T cells, NK cells), neutrophils, macrophages, mast cells, dendritic cells, and others work together to protect the body. The adaptive immune system mounts targeted responses through B cells and T cells, while the innate immune system provides initial defenses using cellular and chemical methods. Key cells include macrophages that phagocytose pathogens and present antigens, B cells that produce antibodies, and T cells that help activate other immune cells and identify and attack infected cells.
This document discusses cellular immune response and the roles of its key components. It describes how antigen presenting cells present antigens to T lymphocytes via MHC molecules, providing the necessary stimulatory and co-stimulatory signals for T cell activation. Activated T cells then differentiate into effector and memory T cells. Effector CD8+ T cells induce apoptosis of infected cells, while effector CD4+ T cells secrete cytokines to activate macrophages. The interactions between these immune cells are regulated by cytokines. The document also discusses antigen presentation pathways, T cell maturation in the thymus, and the roles of superantigens and cytokines in the immune response.
This document summarizes macrophage activation pathways and antimicrobial mechanisms. It discusses how macrophages are activated via classical and alternative pathways stimulated by IFN-γ/TLR agonists and IL-4/IL-13, respectively. The key antimicrobial functions of macrophages are described as phagocytosis, reactive oxygen species production, and lysosomal enzyme activity. Specific mechanisms used by pathogens to evade killing by macrophages are also reviewed.
Immunology (Innate and adaptive immune systems) (ANTIGENS (Ag)) Amany Elsayed
The document provides an overview of immunology and the immune system. It defines key terms like immunity, the immune system, and immune response. It describes the two main branches of the immune system: innate (natural) immunity and adaptive (acquired) immunity. The innate system provides non-specific resistance and is the body's first line of defense. The adaptive system provides antigen-specific immunity and develops memory to enhance the response. The document also outlines the major cells involved in the immune response, including lymphocytes, granulocytes, monocytes, macrophages and dendritic cells. It discusses the functions of phagocytic cells in phagocytosis and intracellular/extracellular killing of pathogens.
The T cell receptor (TCR) is a protein complex found on the surface of T cells that is responsible for recognizing fragments of antigen bound to MHC molecules. It consists of an alpha and beta chain, with 95% of T cells containing these chains and 5% containing gamma and delta chains instead. Each chain contains a variable region that binds the peptide-MHC complex and a constant region near the cell membrane. The variable regions contain three hypervariable complementarity-determining regions important for antigen recognition. The TCR is associated with CD3 proteins that transmit activation signals into the T cell upon peptide binding. TCR diversity arises from genetic recombination of DNA segments during T cell development.
T cells can be categorized into several subsets including helper T cells, cytotoxic T cells, memory T cells, and regulatory T cells. Helper T cells assist other immune cells, cytotoxic T cells destroy infected and tumor cells, memory T cells provide faster responses upon reexposure to pathogens, and regulatory T cells suppress immune activation and prevent autoimmunity. Understanding regulatory T cells in HIV-1 could lead to new immunotherapy or vaccine strategies, but their exact role in HIV-1 pathogenesis requires further study.
This document provides a brief history of immunology, beginning with early observations of immunity in 430 BC by Thucydides. It then discusses the development of variolation to prevent smallpox in the 15th century and Edward Jenner's improvement leading to vaccination in 1798. Major advances included Louis Pasteur's work on vaccines in the late 1800s, the discovery of antibodies and the cellular and molecular basis of immunity in the late 19th/early 20th centuries, and the clonal selection theory in the 1950s establishing the modern paradigm of immunology.
Tumor antigens are substances produced by tumor cells that trigger an immune response. There are two main types: tumor-specific antigens that are unique to tumor cells, produced due to genetic mutations; and tumor-associated antigens that are normally expressed during fetal development but also expressed in tumor cells. The immune system tries to detect and eliminate tumor cells by targeting these antigens, but tumors can evade the immune response through various mechanisms. Immunotherapies aim to enhance the immune response against tumor antigens and defenses against cancer.
Antigen presenting cells such as dendritic cells, macrophages, and B cells play a key role in activating T cells during an immune response. They process foreign antigens, display antigen fragments on MHC molecules, and present these to T cells. This initiation of T cell activation requires two signals: 1) antigen recognition by T cell receptors and 2) co-stimulatory signaling between molecules on the antigen presenting cell and T cell. Together, these signals trigger T cells to proliferate and carry out their immune functions in fighting pathogens or cancer cells.
IMMUNE RESPONSE TO TUMORS-Humoral immunity
-Cellular Immunity- Failure of Host Defenses
- Evasion of Immune Responses by Tumors
- Cancer Immunosurveillance vs Immunoediting- Immunotherapy
The document discusses T cells and B cells. It explains that T cells mature in the thymus gland and recognize antigens bound to MHC molecules, while B cells mature in the bone marrow and recognize free antigens. The document then describes the processes of T cell and B cell activation, differentiation, positive and negative selection, and how they contribute differently to the adaptive immune response.
The document summarizes the key organs of the immune system. It describes the thymus and bone marrow as the primary lymphoid organs where lymphocyte maturation occurs. The lymph nodes, spleen, gut-associated lymphoid tissue, and skin-associated lymphoid tissues are described as the secondary lymphoid organs that trap antigens and allow immune cell interaction. The document also provides examples of how disruption or aging of the primary lymphoid organs like the thymus can impair immune function.
This document discusses the B cell receptor (BCR) and its role in chronic lymphocytic leukemia (CLL). The BCR is composed of immunoglobulin and Igα/Igβ proteins that transmit signals into cells. CLL results when too many B cells become abnormal lymphocytes. In CLL, tonic BCR signaling provides growth signals and plays a key role in disease progression. New drugs target proteins in the BCR pathway like Btk and Syk to block this signaling and stop cancer cell growth and division. Ibrutinib is an approved treatment that inhibits the BCR complex and brings hope to CLL patients.
The document summarizes key aspects of innate immunity. It discusses physical barriers like skin and mucous membranes, as well as cells and proteins involved in innate immunity. Cells discussed include phagocytes like macrophages and neutrophils, which kill microbes via phagocytosis and release of enzymes, reactive oxygen species, and nitric oxide. Proteins of the complement system and acute phase proteins are also summarized. The roles of fever, interferons, and tumor necrosis factors in the innate immune response are briefly described.
The document summarizes the cells and organs of the immune system. It describes how hematopoietic stem cells in the bone marrow give rise to myeloid and lymphoid progenitor cells. These progenitor cells then differentiate into various immune cells including granulocytes, lymphocytes, dendritic cells, macrophages, and others. It also outlines the primary and secondary lymphoid organs including the bone marrow, thymus, spleen, lymph nodes, and mucosal tissues that support the development and activation of immune cells.
The document discusses the various cells of the immune system that are involved in defending the body against pathogens. It describes lymphocytes including T cells, B cells, and natural killer cells. It also discusses other immune cells such as dendritic cells, monocytes, macrophages, neutrophils, eosinophils, basophils, mast cells and their roles. These cells recognize and eliminate pathogens using mechanisms like phagocytosis, antibody production, cytokine secretion and antigen presentation to initiate both innate and adaptive immune responses important for periodontal health.
The immune system functions to eliminate non-self molecules like microbes, cancer cells, and transplanted tissues. It contains central organs like the bone marrow and thymus that produce immune cells, secondary lymphoid tissues that develop these cells, and soluble factors like cytokines. The innate immune system provides non-specific defenses like physical barriers and phagocytes. The adaptive immune system mounts specific responses through B cells and antibodies or T cells. Antibodies mediate humoral immunity against pathogens.
ORGANS OF IMMUNE SYSTEM PRIMARY AND SECONDARY LYMPHOID ORGANSSruthy Chandran
The document summarizes the primary and secondary lymphoid organs of the immune system. The primary lymphoid organs, such as the bone marrow and thymus, are where lymphocytes mature and develop. The secondary lymphoid organs, including lymph nodes, spleen, and mucosa-associated lymphoid tissue (MALT), trap antigens and activate lymphocytes. In these organs, B cells are activated, differentiate into plasma cells, and secrete antibodies to help fight infection.
introduction of adaptive immunity. classification of adaptive immunity, factor affecting it and mechanism of adaptive immunity comparison between adaptive immunity and innate immunity. characteristic of adaptive immunity . cell mediated immune responses immunoglobulins
types of immunoglobulins. functions of immunoglobulins, hypersensitivity reactions
This document summarizes antigen processing and presentation. It discusses that antigen presenting cells such as macrophages, dendritic cells, and B cells express class II MHC molecules and provide co-stimulatory signals to activate T helper cells. These cells internalize antigens through phagocytosis or endocytosis, degrade them into peptides, and present the peptides bound to class II MHC on their surface. The document also describes the major histocompatibility complex and the roles of class I and class II MHC molecules in antigen presentation to T cells. It outlines the exogenous and endogenous antigen processing pathways, how exogenous antigens are presented by class II MHC and endogenous antigens by class I MHC.
The document provides an overview of the immune system, including its main cells and functions. It discusses how immune cells such as lymphocytes (B cells, T cells, NK cells), neutrophils, macrophages, mast cells, dendritic cells, and others work together to protect the body. The adaptive immune system mounts targeted responses through B cells and T cells, while the innate immune system provides initial defenses using cellular and chemical methods. Key cells include macrophages that phagocytose pathogens and present antigens, B cells that produce antibodies, and T cells that help activate other immune cells and identify and attack infected cells.
This document discusses cellular immune response and the roles of its key components. It describes how antigen presenting cells present antigens to T lymphocytes via MHC molecules, providing the necessary stimulatory and co-stimulatory signals for T cell activation. Activated T cells then differentiate into effector and memory T cells. Effector CD8+ T cells induce apoptosis of infected cells, while effector CD4+ T cells secrete cytokines to activate macrophages. The interactions between these immune cells are regulated by cytokines. The document also discusses antigen presentation pathways, T cell maturation in the thymus, and the roles of superantigens and cytokines in the immune response.
This document summarizes macrophage activation pathways and antimicrobial mechanisms. It discusses how macrophages are activated via classical and alternative pathways stimulated by IFN-γ/TLR agonists and IL-4/IL-13, respectively. The key antimicrobial functions of macrophages are described as phagocytosis, reactive oxygen species production, and lysosomal enzyme activity. Specific mechanisms used by pathogens to evade killing by macrophages are also reviewed.
Immunology (Innate and adaptive immune systems) (ANTIGENS (Ag)) Amany Elsayed
The document provides an overview of immunology and the immune system. It defines key terms like immunity, the immune system, and immune response. It describes the two main branches of the immune system: innate (natural) immunity and adaptive (acquired) immunity. The innate system provides non-specific resistance and is the body's first line of defense. The adaptive system provides antigen-specific immunity and develops memory to enhance the response. The document also outlines the major cells involved in the immune response, including lymphocytes, granulocytes, monocytes, macrophages and dendritic cells. It discusses the functions of phagocytic cells in phagocytosis and intracellular/extracellular killing of pathogens.
The T cell receptor (TCR) is a protein complex found on the surface of T cells that is responsible for recognizing fragments of antigen bound to MHC molecules. It consists of an alpha and beta chain, with 95% of T cells containing these chains and 5% containing gamma and delta chains instead. Each chain contains a variable region that binds the peptide-MHC complex and a constant region near the cell membrane. The variable regions contain three hypervariable complementarity-determining regions important for antigen recognition. The TCR is associated with CD3 proteins that transmit activation signals into the T cell upon peptide binding. TCR diversity arises from genetic recombination of DNA segments during T cell development.
T cells can be categorized into several subsets including helper T cells, cytotoxic T cells, memory T cells, and regulatory T cells. Helper T cells assist other immune cells, cytotoxic T cells destroy infected and tumor cells, memory T cells provide faster responses upon reexposure to pathogens, and regulatory T cells suppress immune activation and prevent autoimmunity. Understanding regulatory T cells in HIV-1 could lead to new immunotherapy or vaccine strategies, but their exact role in HIV-1 pathogenesis requires further study.
This document provides a brief history of immunology, beginning with early observations of immunity in 430 BC by Thucydides. It then discusses the development of variolation to prevent smallpox in the 15th century and Edward Jenner's improvement leading to vaccination in 1798. Major advances included Louis Pasteur's work on vaccines in the late 1800s, the discovery of antibodies and the cellular and molecular basis of immunity in the late 19th/early 20th centuries, and the clonal selection theory in the 1950s establishing the modern paradigm of immunology.
Tumor antigens are substances produced by tumor cells that trigger an immune response. There are two main types: tumor-specific antigens that are unique to tumor cells, produced due to genetic mutations; and tumor-associated antigens that are normally expressed during fetal development but also expressed in tumor cells. The immune system tries to detect and eliminate tumor cells by targeting these antigens, but tumors can evade the immune response through various mechanisms. Immunotherapies aim to enhance the immune response against tumor antigens and defenses against cancer.
Antigen presenting cells such as dendritic cells, macrophages, and B cells play a key role in activating T cells during an immune response. They process foreign antigens, display antigen fragments on MHC molecules, and present these to T cells. This initiation of T cell activation requires two signals: 1) antigen recognition by T cell receptors and 2) co-stimulatory signaling between molecules on the antigen presenting cell and T cell. Together, these signals trigger T cells to proliferate and carry out their immune functions in fighting pathogens or cancer cells.
IMMUNE RESPONSE TO TUMORS-Humoral immunity
-Cellular Immunity- Failure of Host Defenses
- Evasion of Immune Responses by Tumors
- Cancer Immunosurveillance vs Immunoediting- Immunotherapy
The document discusses T cells and B cells. It explains that T cells mature in the thymus gland and recognize antigens bound to MHC molecules, while B cells mature in the bone marrow and recognize free antigens. The document then describes the processes of T cell and B cell activation, differentiation, positive and negative selection, and how they contribute differently to the adaptive immune response.
The document summarizes the key organs of the immune system. It describes the thymus and bone marrow as the primary lymphoid organs where lymphocyte maturation occurs. The lymph nodes, spleen, gut-associated lymphoid tissue, and skin-associated lymphoid tissues are described as the secondary lymphoid organs that trap antigens and allow immune cell interaction. The document also provides examples of how disruption or aging of the primary lymphoid organs like the thymus can impair immune function.
This document discusses the B cell receptor (BCR) and its role in chronic lymphocytic leukemia (CLL). The BCR is composed of immunoglobulin and Igα/Igβ proteins that transmit signals into cells. CLL results when too many B cells become abnormal lymphocytes. In CLL, tonic BCR signaling provides growth signals and plays a key role in disease progression. New drugs target proteins in the BCR pathway like Btk and Syk to block this signaling and stop cancer cell growth and division. Ibrutinib is an approved treatment that inhibits the BCR complex and brings hope to CLL patients.
The document summarizes key aspects of innate immunity. It discusses physical barriers like skin and mucous membranes, as well as cells and proteins involved in innate immunity. Cells discussed include phagocytes like macrophages and neutrophils, which kill microbes via phagocytosis and release of enzymes, reactive oxygen species, and nitric oxide. Proteins of the complement system and acute phase proteins are also summarized. The roles of fever, interferons, and tumor necrosis factors in the innate immune response are briefly described.
The document summarizes the cells and organs of the immune system. It describes how hematopoietic stem cells in the bone marrow give rise to myeloid and lymphoid progenitor cells. These progenitor cells then differentiate into various immune cells including granulocytes, lymphocytes, dendritic cells, macrophages, and others. It also outlines the primary and secondary lymphoid organs including the bone marrow, thymus, spleen, lymph nodes, and mucosal tissues that support the development and activation of immune cells.
The document discusses the various cells of the immune system that are involved in defending the body against pathogens. It describes lymphocytes including T cells, B cells, and natural killer cells. It also discusses other immune cells such as dendritic cells, monocytes, macrophages, neutrophils, eosinophils, basophils, mast cells and their roles. These cells recognize and eliminate pathogens using mechanisms like phagocytosis, antibody production, cytokine secretion and antigen presentation to initiate both innate and adaptive immune responses important for periodontal health.
The immune system functions to eliminate non-self molecules like microbes, cancer cells, and transplanted tissues. It contains central organs like the bone marrow and thymus that produce immune cells, secondary lymphoid tissues that develop these cells, and soluble factors like cytokines. The innate immune system provides non-specific defenses like physical barriers and phagocytes. The adaptive immune system mounts specific responses through B cells and antibodies or T cells. Antibodies mediate humoral immunity against pathogens.
This document discusses the cells of the immune system that are involved in the host response to periodontal pathogens. It describes the main immune cells, including lymphocytes (B cells, T cells, natural killer cells), phagocytes (neutrophils, macrophages, dendritic cells), mast cells, basophils, and eosinophils. It explains the functions of these cells, such as phagocytosis, antigen presentation, and secretion of inflammatory mediators. The document also discusses innate immunity, cell-mediated immunity, and their roles in periodontal disease.
White blood cells (leukocytes) play an important role in immune responses and tissue maintenance. There are two main types - polymorphonuclear granulocytes which have lobed nuclei and cytoplasmic granules, and mononuclear agranulocytes which lack granules and have large nuclei. Neutrophils, eosinophils, basophils, lymphocytes and monocytes are the major leukocyte types and each plays distinct roles in immune function and response to pathogens. Leukocytes are produced through myeloid and lymphoid stem cell lineages in the bone marrow.
The document summarizes the major cells and tissues of the immune system. It discusses 10 different immune cells: eosinophils, macrophages, neutrophils, monocytes, dendritic cells, mast cells, basophiles, natural killer cells, platelets, and lymphocytes. For each cell type, it provides a brief description of their role, including phagocytosis of pathogens, antigen presentation, allergic responses, and adaptive immune functions. The document also mentions hematopoiesis, the process where stem cells in the bone marrow differentiate into the various blood cell types.
Lymphocytes are the main cells of the immune system and are responsible for the specific immune response. There are two main types of lymphocytes - T lymphocytes and B lymphocytes. T lymphocytes attack invaders directly through cell-mediated immunity, while B lymphocytes produce antibodies and perform antibody-mediated immunity against bacteria. Natural killer cells provide immediate defense against viruses and cancer cells by destroying infected or malignant cells upon first exposure. Monocytes circulate in the blood and differentiate into tissue macrophages that phagocytose pathogens. Dendritic cells present antigens to lymphocytes to initiate immune responses.
This slide covers briefly how intracellular and extracellular bacteria elicits an immune response, how bacteria evade from the immune system, what complement system is, opsonization, neutralisation, septic shock, sepsis, superantigens, phagocytosis, interleukins, Toll-like receptors, a list of diseases caused by bacterias and their names etc.
The document discusses the role of phagocytes, specifically macrophages and neutrophils, in the innate immune response against infection. It describes how neutrophils are recruited from the bloodstream to sites of infection through endothelial activation, rolling, arrest, and migration in response to inflammatory signals. It also outlines the mechanisms phagocytes use to kill pathogens, including enzymatic degradation within phagosomes that fuse with lysosomes/granules, and reactive oxygen and nitrogen species produced during respiratory bursts. Phagocytes play a key role in the early innate immune response by removing pathogens, infected cells, and cellular debris.
The immune system has two main branches - innate immunity which provides broad and immediate protection against pathogens, and adaptive immunity which provides pathogen-specific protection through immune cells and antibodies. The adaptive immune system includes B cells that produce antibodies and T cells that identify and destroy infected cells. Antibodies are Y-shaped proteins produced by B cells that recognize pathogens by binding to them, marking them for destruction. They have a variable region that binds antigens and a constant region that activates immune responses. The classes of antibodies include IgG, IgM, IgA, IgD and IgE which have different structures and functions.
An essential aspect of the immune response is the ability to recognize almost limitless numbers of foreign cells and nonself substances, distinguishing them from self molecules that are native to the body – it distinguishes self from nonself.
L1 The_Immune_Response immune system is clearly essential for survival. .pptwalealufa
It also detects and responds to abnormal cells and molecules that periodically develop in the body so that diseases such as cancers do not occur.
An essential aspect of the immune response is the ability to recognize almost limitless numbers of foreign cells and nonself substances, distinguishing them from self molecules that are native to the body – it distinguishes self from nonself.
Dr. Alok Tripathi studies immunology at the Department of Biotechnology. The document discusses the history and key concepts of immunology, including:
1. The dual immune system of vertebrates, consisting of cell-mediated and humoral immunity.
2. Early theories on immunity proposed by scientists like Metchnikoff, von Behring, and Paul Ehrlich to explain concepts like phagocytosis, humoral immunity, and the generation of antibody diversity.
3. The development of the clonal selection theory by Burnet, Jerne, and others to explain how the immune system achieves antigen specificity through clonal expansion and memory cells.
Types of immune cells
∆Lymphoid cells
-lymphocytes
constitute 20%–40% of the body’s white blood cells and 99% of the cells in the lymph
continually circulate in the blood and lymph and are capable of migrating into the tissue spaces and lymphoid organs
lymphocytes enlarge into 15 µm-diameter blast cells, called lymphoblasts; these cells have a higher cytoplasm : nucleus ratio and more organellar complexity than small lymphocytes.
Lymphoblasts proliferate and eventually differentiate into-
effector cells or into
memory cells.
* B-lymphocytes
*T-lymphocytes
* Natural killer cells
∆mononuclear phagocytes
The mononuclear phagocytic system consists of monocytes circulating in the blood and macrophages in the tissues.
-macrophages
-monocytes
∆granulocytes cells
Granulocytes are at the front lines of attack during an immune response and are considered part of the innate immune system.
Granulocytes are white blood cells (leukocytes) that are classified as neutrophils, basophils, mast cells, or eosinophils on the basis of differences in cellular morphology and the staining of their characteristic cytoplasmic granules
The cytoplasm of all granulocytes is replete with granules that are released in response to contact with pathogens.
These granules contain a variety of proteins with distinct functions:
Some damage pathogens directly;
some regulate trafficking and activity of other white blood cells, including lymphocytes
-neutrophills
-basophils
-eosinophils
-dendritic cells
-mast cells
Cells of the immune system - immunology by S. Afna Afnaafi2
This document provides an overview of the major cells of the immune system, including their origins, functions, and roles in immunity. It discusses innate immune cells like natural killer cells, neutrophils, macrophages, and dendritic cells. It also examines adaptive immune cells such as T cells, B cells, and NKT cells. The document describes how these cells develop, recognize pathogens, and mount immune responses to protect the body.
This document summarizes the cells involved in the innate and adaptive immune system. The innate immune system contains myeloid cells like neutrophils, eosinophils, basophils, mast cells, monocytes, macrophages, and dendritic cells that provide non-specific first line defense against pathogens. The adaptive immune system contains lymphocytes like T cells and B cells that provide specialized and targeted defense. T cells regulate the immune response and destroy intracellular pathogens. B cells produce antibodies for specific antigens encountered.
The document discusses innate immunity. It describes the components of innate immunity including epithelial surfaces, antimicrobial substances in blood and tissues, fever, acute phase proteins, and cells of the innate immune system such as phagocytes (macrophages and neutrophils), mast cells, basophils, eosinophils, and platelets. These components provide non-specific defenses that help the body resist infection.
The document summarizes key components and processes of the immune system. It describes phagocytosis, antibodies and antigens, immunity, and the complement system. Phagocytosis involves immune cells ingesting foreign particles. Antibodies are Y-shaped proteins that bind to antigens like bacteria and viruses to help immune cells identify and neutralize pathogens. The complement system utilizes three pathways - classical, lectin, and alternative - that converge into a membrane attack complex to help kill microbes. Cytokines are cell signaling proteins like interleukins that help activate and coordinate the immune response.
The document discusses the cells and tissues of the immune system. It describes that immune cells are derived from stem cells and develop through myeloid or lymphoid lineages. The main immune cells include lymphocytes (B cells, T cells, NK cells), phagocytes (neutrophils, macrophages, dendritic cells), eosinophils, basophils, and mast cells. The tissues that support the immune system are primary lymphoid organs like the bone marrow and thymus, where immune cells develop, and secondary lymphoid organs like lymph nodes, spleen and mucosal tissues, where immune responses are initiated.
Basic immunology and hypersensitive disorders bebaBISRATGETACHEWMD
This document provides an overview of basic immunology and hypersensitivity disorders. It describes the innate and adaptive immune systems, including the cells involved such as neutrophils, eosinophils, basophils, monocytes, T lymphocytes and B lymphocytes. It discusses the mechanisms of cell-mediated and humoral immunity. It also provides details on antimicrobial peptides, complement system, antigen presentation and the roles of cytokines in immune responses.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptxRASHMI M G
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
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Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
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Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
2. Outline
Introduction
Formation of blood cells
Types of leucocytes
Cells of the innate immune system
Phagocytosis and intracellular killing
Cells of the adaptive immune system
Cell-Mediated Cytotoxicity
Immunopathology
Conclusion
References
3. Presentation Objectives
To identify cell types involved in the innate
and adaptive immune response.
To highlight the mechanism of combating
infection/disease (killing pathogens).
To identify the consequences of alteration
in function of the immune cells.
4. Introduction
White blood cells or leucocytes serve as sentinels and
defenders against infection.
They move around the body via the lymphatic and blood
circulatory systems.
Leucocytes are classified by morphology- number of nuclei
lobes and presence or absence of cytoplasmic granules.
Leukocytes may be found as individual cells throughout the
body, as accumulations within lymphoid organs (e.g., spleen,
lymph nodes) and at sites of infection or inflammation.
Knowledge of the role that each leukocyte plays is important to
5. Formation of blood cells
All bloodborne cells originate in the bone marrow.
Pluripotent hematopoietic stem cell in the bone
marrow give rise to two major lineages; a myeloid
lineage and a lymphoid lineage.
Cells of the myeloid lineage differentiate further into
platelets, erythrocytes, eosinophils, basophils (and
mast cells), neutrophils, monocytes/macrophages,
and some dendritic cells.
Cells of the lymphoid lineage differentiate further
into T and B lymphocytes, NK cells, and some
7. Types of leucocytes
White blood cells that have multilobed nuclei
and contain conspicuous cytoplasmic granules
are known as granulocytes .
Others with a single, unlobed nucleus and
cytoplasm that contains few or no granules are
known as agranular leukocytes.
Agranular leukocytes derive from lymphoid or
myeloid lineage precursors and account for
approximately 35% to 38% of the leukocytes in
9. Cells of the innate immune system
Myeloid Cells: First line of defense against
invading organisms in non-specific innate
immunity.
Neutrophils
Eosinophils
Basophils/Mast cells
Monocytes/Macrophages/Dendritic
Cells
Lymphoid Cells:
10. Neutrophils
Comprises approximately 60% of the peripheral blood
leukocytes, neutrophils are the most numerous
leukocyte population.
– Neutrophils have multi lobed nuclei (2-5) and cytoplasmic granules that
stain with both acid and basic dyes.
– often called polymorphonuclear cells (PMN's).
The neutrophil's main role is in inflammation.
– First to arrive at inflammation site
– Leave blood/endothelium into tissue (extravasation).
Neutrophils are attracted into the tissue by chemotactic
factors stimulated by tissue damage
– complement proteins, clotting
proteins and T cell derived
11. In the tissues, neutrophils are active
phagocytes.
They destroy ingested microorganisms via
oxygen-dependent or independent
pathways.
Produce myeloperoxidases to assist oxidated antimicrobial effects.
Produce lactoferrin and lysozyme as direct antimicrobial agents.
Produce leukotrienes and prostaglandins, products of the lipoxygenase
and cyclo-oxygenase pathways, to mediate vascular functions.
Deficiencies in pathways increase susceptibility
to infections.
12. Characteristics of Neutrophil
granules
Primary granules Secondary granules
Azurophilic; young neutrophils Specific for mature neutrophils
Contain:
cationic proteins, lysozyme, defensins,
elastase and
Contain:
Lysozyme,
NADPH oxidase components and
myeloperoxidase Lactoferrin and B12-binding protein
13. Eosinophils
Eosinophils have bilobed nuclei and
cytoplasmic granules that stain with the
acid dye eosin (hence its name).
Constitute 1%-3% of circulating
leucocytes.
Involved in asthma.
Eosinophils are motile, sometimes
phagocytic, and are particularly
active in parasitic infection.
14. Basophils
Basophils have bilobed nuclei and cytoplasmic
granules that stain with the basic dye methylene
blue.
Found in low numbers in the blood (<1%). Act like mast cells.
They are nonphagocytic
Involved in allergic reactions (Type I hypersensitivity
responses).
Have high affinity Fc receptors for IgE on their surface.
When an individual is exposed to an allergen, specific IgE is
produced. This IgE binds to the surface of basophils.
Upon re-exposure to the allergen, the allergen binds to IgE on the
surface of basophils resulting in degranulation.
Cross-linking of the IgE causes the basophils
to release pharmacologically active mediators
15. Mast cells
Similar importance in allergic reactions as
basophils, but only found in tissues.
Contain granules with preformed
mediators to be released after stimulation
– histamine, prostaglandins
– leukotrienes
Stimulation of mast cells occurs by the
anaphylatoxins (complement proteins C3a
and C5a) or by cross-linking of surface
immunoglobulin (IgE).
16. Monocytes/Macrophages
Circulate in the blood after leaving the bone marrow.
Survive only a day or so before they enter the tissue to
mature into macrophages.
Involved in phagocytosis and intracellular killing of
microorganisms.
Generation of toxic metabolites through respiratory burst.
Production of nitric oxide, hydrogen peroxide, superoxide
anion.
Monocytes/Macrophages are antigen processing and
presenting cells.
Degrative enzymes in lysosomal granules.
Chew ingested proteins.
Present to adaptive cells.
17. Macrophages
When monocytes enter the tissues and become
macrophages:
– Enlarge and increase production of intracellular
lysozymes
– Greater phagocytosis.
– Can live for years in tissue; highly motile.
Activation of these cells occurs by phagocytosis
of antigens, or in response to T cell derived
cytokines.
Activated macrophages recognize and remove
unwanted particulate matter including products
18. After activation, these cells secrete cytokines, chemokines,
lysozymes and other factors to upregulate immune
response. In chronic inflammation, macrophage
scavengers can become “giant cells” or “foamy
macrophages”.
Fig: Electron micrograph of macrophag
19. Dendritic cells
Specialized phagocytic cells found in most tissues.
Arise both from the myeloid and lymphoid lineages.
Abundant at interfaces between the external and internal
environments (skin, lining of the gastrointestinal tract), where
they encounter invading pathogens.
Actively motile; continuously sample surroundings by endocytic
processes.
Dendritic cells are very efficient at activation of T cells.
20. Natural Killer cells
Also known as large granular lymphocytes (LGLs)
Functionally cytotoxic representing an innate population that kill virally
infected or tumor target cells.
Killing is nonspecific - they do not need to recognize foreign antigens
presented on the target cell.
– NK cells do not have a specific cell receptor. Target recognition occurs by a Killer Inhibitory Receptor, KIR,
which assess MHC I molecules on the target cell surface. MHC 1 molecule is lacking on infected and tumor
targets.
Kill targets by releasing perforin which damages target cell membranes. Can also
induce apoptosis in the target cell.
NK cells is different from NK T cells.
-NKT cells has some of the attributes of T cell and NK cell.
Like T cells, NK1-T cells have T cell receptors
(TCRs).Unlike most T cells, the TCRs of NK1-T cells interact
with MHC-like molecules called CD1 rather than with
class I or class II MHC molecules. Like NK cells, they have
variable levels of CD16 and other receptors typical of NK
21. Phagocytosis and intracellular
killing
Phagocytosis is the engulfment and degradation of microbes and
other particulate matter by cells such as macrophages/monocytes,
dend ritic cells, and neutrophils .
Steps in phagocytosis-
1) Detection of the foreign particle and movement of the phagocyte to the area
by chemotaxis.
2) Attachment of the foreign particle to the phagocyte.
3) Engulfment or ingestion of the foreign particle into a vesicle called a
phagosome.
4) Fusion with lysosome and formation of the phagolysosome.
5) Intracellular killing and digestion.
6) In the case of macrophages, egestion and antigen presentation.
Phagocytes detect microbes by the presence of N-formylated
peptides, activated complement proteins and the mediators of
inflammation.
Phagocytes attach to microbes using opsonins, such as IgG and the
complement protein C3b. In the absence of opsonins, phagocytes can
23. Pathways of intracellular killing
Lysosomes employ multiple mechanisms for
killing and degrading ingested microbe. These
include;
Oxygen-independent killing
Oxygen-dependent-MPO independent killing
Oxygen-dependent-MPO dependent killing
Nitric Oxide mediated killing
In oxygen-independent killing, activated
phagocytes synthesize lysozyme and various
hydrolytic enzymes whose degradative
activities do not require oxygen.
24. Mediators of oxygen-independent
killing in phagolysosome
During phagocytosis there is an increase in glucose and oxygen
consumption which is referred to as the respiratory burst.
The consequence of the respiratory burst is that a number of
oxygen-containing compounds are produced which kill the
bacteria being phagocytosed. This is referred to as oxygen-
Effector Molecule Function
Cationic proteins (cathepsin)
Damage to microbial
membranes
Lysozyme
Hydrolyses mucopeptides in
the cell wall
Lactoferrin Deprives pathogens of iron
Hydrolytic enzymes (proteases) Digests killed organisms
27. Nitric oxide-dependent killing
Once microorganisms are destroyed, the unwanted organic
material is expelled from the cell in a process
called egestion.
Egestion is the opposite of ingestion and the molecular
mechanism is basically the reverse of phagocytosis with
the microbial leftovers being dumped into the blood and
lymph.
Some of this microbial debris are not egested, but binds to
special protein complexes (called Major Histocompatibility
Complex molecules) on the membranes of macrophages
28. Cells of the adaptive immune
system
Adaptive immune responses are mediated by a
specialized group of leukocytes, the
lymphocytes, which include T and B
lymphocytes (T cells and B cells) that
specifically recognize foreign material or
antigens.
All lymphocytes are derived from bone marrow
stem cells, but T cells then develop in the
thymus, while B cells develop in the bone
29. B Lymphocytes
Develop from stem cells in the bone marrow.
Produce antibodies with specificity for antigens and display
it on their surfaces to function as BCRs.
Integral in humoral immunity
Plasma cells = terminally differentiated B cells that secrete
immunoglobulins.
Memory cells- secondary immune response is swifter and
stronger.
Upon activation, a B cell can switch to produce a
different class of antibody, with the same antigen
specificity.
Activation into antibody secreting cells is antigen-
dependent.
30. T-Lymphocytes
T lymphocytes develop in the thymus.
Regulate immune responses.
Integral in cell mediated immunity.
Critical in B cell-antibody production.
Mature T cells display either CD4 or CD8.
Cells with a CD4 marker are called helper T cells (Th cells).
CD8 marker positive cells are cytotoxic T cells (Tc cells).
There are several different types of T cell, and they
have a variety of functions :
Type 1 helper T cells or TH1 cells - interacts with mononuclear phagocytes and
helps them destroy intracellular pathogens•
Type 2 helper T cells or TH2 cells; interacts with B cells and helps them to
divide, differentiate, and make antibody•
Cytotoxic T lymphocytes (CTLs or TC cells). responsible for the destruction of
host cells that have become infected by viruses or other intracellular pathogens.
Regulatory T cells or Tregs, help to control the development of immune
responses, and limit reactions against self tissues.
32. Cell-Mediated Cytotoxicity
Cytotoxicity describes the ways in which leukocytes
recognize and destroy other cells.
Cell-mediated cytotoxicity is an essential defense against:
intracellular pathogens, including viruses;
some bacteria;
some parasites.
Tumor cells, eukaryotic pathogens, and even cells of the body
may also become the target of cytotoxic cells.
Several types of cell have cytotoxic activity including:
cytotoxic T lymphocytes (CTLs);
natural killer (NK) cells
CTLs and NK cells use a variety of different mechanisms to
kill their targets. These include:
direct cell–cell signaling via surface molecules; and
granule-associated killing
33.
34. Immunopathology
Autoimmune disease - When the immune system reacts
against ‘self’ components, for example rheumatoid arthritis
or pernicious anemia.
Immunodeficiency- If any elements of the immune system
are defective, the individual may not be able to fight
infections adequately.
primary immundeficiencies are hereditary and start to manifest shortly
after birth; eg chronic granulomatous disease (CGD) and leukocyte
adhesion deficiency (LAD).
Secondary immunodeficiencies develop later in life, for example the
acquired immune deficiency syndrome (AIDS).
Hypersensitivity- Sometimes immune reactions are out of
all proportion to the damage that may be caused by a
pathogen. The immune system may also mount a reaction
to a harmless antigen, such as a food molecule causing
36. Conclusion
The immune system has evolved to protect us from
pathogens.
Phagocytes and lymphocytes are key mediators of
immunity. Phagocytes internalize pathogens and degrade
them. Lymphocytes (B and T cells) have receptors that
recognize specific molecular components of pathogens
and have specialized functions. B cells make antibodies
(effective against extracellular pathogens), cytotoxic T
lymphocytes (CTLs) kill virally infected cells, and helper T
cells coordinate the immune response by direct cell–cell
interactions and the release of cytokines.
The immune system may fail (immunopathology). This can
be a result of immunodeficiency, hypersensitivity, or
37. References
Doan, T., Melvold, R., Viselli, S. and Waltenbaugh,
C.(2013). Lippincott’s illustrated reviews
Immunology. Philadelphia, 2nd Edn. Lippincott
Williams & Wilkins. ISBN 978-1-4511-0937-5.
Kindt, T.J., Osborne, B.A. and Goldsby, R.A.
(2006). Kuby Immunology, 6th edn. Oxford: WH
Freeman.
Male, D., Brostoff, J., Roth, D.B. and Roitt, I.(2013).
Immunology. China, 8th Edn. Elsevier. ISBN 978-0-
702-04548-6.
Roitt, I.M. and Delves, P. (2011)Essential