Immunological tolerance
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Immune tolerance
This document discusses antigens, self-tolerance, and the mechanisms by which the immune system avoids attacking self-antigens. It explains that lymphocytes can recognize virtually any antigen due to random rearrangement of gene segments. While autoreactive lymphocytes are constantly generated, the immune system remains tolerant of self-antigens through central and peripheral tolerance mechanisms. Central tolerance eliminates many autoreactive T and B cells early in development in primary lymphoid organs. Peripheral tolerance then controls responses of mature lymphocytes to self-antigens in secondary lymphoid organs.
Immune tolerance
Immune tolerance is induced through central and peripheral mechanisms that eliminate or suppress self-reactive immune cells. Central tolerance occurs in the thymus and bone marrow where high-affinity self-reactive T and B cells undergo apoptosis or receptor editing. Peripheral tolerance includes anergy induction, suppression by regulatory T cells (Tregs), and inhibition by receptors like CTLA-4 and PD-1. Tregs expressing the transcription factor FoxP3 are critical for maintaining tolerance and preventing autoimmunity. Failure of these tolerance mechanisms can lead to autoimmune disease.
Humoral Immunity
- Naive B cells express IgM and IgD antibodies on their surface that recognize antigens. Upon activation, a single B cell can produce up to 10^12 antibody molecules per day through plasma cell differentiation.
- Repeated antigen exposure leads to affinity maturation through somatic hypermutation in germinal centers, increasing antibody affinity over time. Helper T cells are required for isotype switching and affinity maturation.
- Engagement of complement receptors and toll-like receptors enhances B cell activation and antibody production. Activated B cells also upregulate costimulators to amplify helper T cell responses.
Immunology
The immune system consists of cells, proteins, and lymphoid organs that work together to protect the body from infection. The immune system has two branches: innate immunity provides a general and immediate response, while adaptive immunity provides a tailored response after initial exposure. Innate immunity involves physical barriers and cells like macrophages that recognize pathogens. Adaptive immunity involves B and T cells that recognize specific pathogens and mount stronger responses upon reexposure. Cytokines are proteins that regulate immune cell growth and activation and mediate inflammatory responses.
Autoimmunity
Autoimmunity occurs when the immune system fails to recognize self antigens and mounts an immune response against the body's own cells and tissues, leading to autoimmune disease. The immune system normally develops tolerance through central and peripheral mechanisms to distinguish self from non-self. A breakdown in tolerance can result from genetic susceptibility and environmental triggers like infections that cause molecular mimicry or tissue damage releasing self antigens. Autoimmune diseases are classified as organ-specific if they target a single organ, or systemic if affecting multiple body systems.
Adaptive immunity. by mateen irfansha
Adaptive immunity is induced in response to specific antigens after collaboration between phagocytic cells, T and B lymphocytes, and production of immunoglobulins and lymphokines. There are two types of adaptive immunity: humoral immunity mediated by secreted antibodies and cell-mediated immunity which activates phagocytes, natural killer cells, cytotoxic T-lymphocytes and cytokines without antibodies. Humoral immunity involves B cell transformation into plasma cells secreting antibodies, while cell-mediated immunity blocks intracellular microbes by activating macrophages or cytotoxic T cells killing infected cells.
Immunological tolerance dr.ihsan alsaimary
Dr. ihsan edan abdulkareem alsaimary
PROFESSOR IN MEDICAL MICROBIOLOGY AND MOLECULAR IMMUNOLOGY
ihsanalsaimary@gmail.com
mobile : 009647801410838
university of basrah - college of medicine - basrah -IRAQ
No 13 immunological_tolerance
The document discusses the history and mechanisms of immunological tolerance. It describes how Owen first observed that sharing a blood system in utero led to tolerance between non-identical twins. Burnet then postulated that there is a window during immune system immaturity where antigens can induce tolerance. Medawar found lifelong tolerance could be induced by transferring cells in early life but not later. The document also discusses the "danger hypothesis" and controlled cell death in preventing autoimmunity.
Recommended
Immune tolerance
This document discusses antigens, self-tolerance, and the mechanisms by which the immune system avoids attacking self-antigens. It explains that lymphocytes can recognize virtually any antigen due to random rearrangement of gene segments. While autoreactive lymphocytes are constantly generated, the immune system remains tolerant of self-antigens through central and peripheral tolerance mechanisms. Central tolerance eliminates many autoreactive T and B cells early in development in primary lymphoid organs. Peripheral tolerance then controls responses of mature lymphocytes to self-antigens in secondary lymphoid organs.
Immune tolerance
Immune tolerance is induced through central and peripheral mechanisms that eliminate or suppress self-reactive immune cells. Central tolerance occurs in the thymus and bone marrow where high-affinity self-reactive T and B cells undergo apoptosis or receptor editing. Peripheral tolerance includes anergy induction, suppression by regulatory T cells (Tregs), and inhibition by receptors like CTLA-4 and PD-1. Tregs expressing the transcription factor FoxP3 are critical for maintaining tolerance and preventing autoimmunity. Failure of these tolerance mechanisms can lead to autoimmune disease.
Humoral Immunity
- Naive B cells express IgM and IgD antibodies on their surface that recognize antigens. Upon activation, a single B cell can produce up to 10^12 antibody molecules per day through plasma cell differentiation.
- Repeated antigen exposure leads to affinity maturation through somatic hypermutation in germinal centers, increasing antibody affinity over time. Helper T cells are required for isotype switching and affinity maturation.
- Engagement of complement receptors and toll-like receptors enhances B cell activation and antibody production. Activated B cells also upregulate costimulators to amplify helper T cell responses.
Immunology
The immune system consists of cells, proteins, and lymphoid organs that work together to protect the body from infection. The immune system has two branches: innate immunity provides a general and immediate response, while adaptive immunity provides a tailored response after initial exposure. Innate immunity involves physical barriers and cells like macrophages that recognize pathogens. Adaptive immunity involves B and T cells that recognize specific pathogens and mount stronger responses upon reexposure. Cytokines are proteins that regulate immune cell growth and activation and mediate inflammatory responses.
Autoimmunity
Autoimmunity occurs when the immune system fails to recognize self antigens and mounts an immune response against the body's own cells and tissues, leading to autoimmune disease. The immune system normally develops tolerance through central and peripheral mechanisms to distinguish self from non-self. A breakdown in tolerance can result from genetic susceptibility and environmental triggers like infections that cause molecular mimicry or tissue damage releasing self antigens. Autoimmune diseases are classified as organ-specific if they target a single organ, or systemic if affecting multiple body systems.
Adaptive immunity. by mateen irfansha
Adaptive immunity is induced in response to specific antigens after collaboration between phagocytic cells, T and B lymphocytes, and production of immunoglobulins and lymphokines. There are two types of adaptive immunity: humoral immunity mediated by secreted antibodies and cell-mediated immunity which activates phagocytes, natural killer cells, cytotoxic T-lymphocytes and cytokines without antibodies. Humoral immunity involves B cell transformation into plasma cells secreting antibodies, while cell-mediated immunity blocks intracellular microbes by activating macrophages or cytotoxic T cells killing infected cells.
Immunological tolerance dr.ihsan alsaimary
Dr. ihsan edan abdulkareem alsaimary
PROFESSOR IN MEDICAL MICROBIOLOGY AND MOLECULAR IMMUNOLOGY
ihsanalsaimary@gmail.com
mobile : 009647801410838
university of basrah - college of medicine - basrah -IRAQ
No 13 immunological_tolerance
The document discusses the history and mechanisms of immunological tolerance. It describes how Owen first observed that sharing a blood system in utero led to tolerance between non-identical twins. Burnet then postulated that there is a window during immune system immaturity where antigens can induce tolerance. Medawar found lifelong tolerance could be induced by transferring cells in early life but not later. The document also discusses the "danger hypothesis" and controlled cell death in preventing autoimmunity.
Autoimmunity and Tolerance
The document discusses immunological tolerance and its breakdown which can lead to autoimmunity and autoimmune diseases. It explains the mechanisms of central and peripheral tolerance that normally prevent immune responses against self-antigens. Failure of these tolerance mechanisms can occur through various causes like a breakdown of T cell anergy or loss of regulatory T cells, resulting in an immune response against self-tissues and the development of autoimmune conditions.
Autoimmunity
This document discusses immunological tolerance and autoimmunity. It defines central and peripheral tolerance as mechanisms by which the immune system learns to distinguish self from non-self. Central tolerance involves deletion of self-reactive lymphocytes in the thymus and bone marrow. Peripheral tolerance mechanisms include clonal deletion, anergy, and suppression. Failure of tolerance can lead to autoimmune diseases, which are influenced by genetic, hormonal, and environmental factors. Common triggers include molecular mimicry between microbial and self-antigens.
Adaptive immunity
The document discusses adaptive immunity and the specific immune response. It describes how adaptive immunity provides lifelong protective immunity through antigen-specific responses that are mediated by lymphocytes, including B cells, T cells, helper T cells, and killer T cells. Lymphocytes have antigen receptors like the B cell receptor and T cell receptor that provide specificity. The adaptive immune response develops over a person's lifetime through somatic recombination and clonal selection that generates a diverse repertoire of lymphocytes each with a unique receptor.
T CELL ACTIVATION AND IT'S TERMINATION
T cell activation requires two signals: 1) recognition of antigens displayed on antigen-presenting cells by T cell receptors and 2) co-stimulatory signals through molecules like CD28. This leads T cells to proliferate, differentiate into effector and memory cells, and perform effector functions. Proper activation requires interaction between T cells and antigen-presenting cells in lymphoid tissues, where costimulatory molecules are highly expressed. Dysregulation of T cell activation can lead to autoimmunity or susceptibility to infection.
Immunological tolerance
This document discusses immunological tolerance and regulatory T cells. It defines tolerance as unresponsiveness to antigen induced by previous exposure. Central tolerance occurs in the thymus through deletion of self-reactive T cells. Peripheral tolerance occurs through several mechanisms in tissues, including regulatory T cells that suppress immune responses. The key transcription factor controlling regulatory T cells is FOXP3. Mutations in FOXP3 can lead to immune dysregulation diseases like IPEX syndrome.
AUTOIMMUNITY
This document provides an overview of autoimmune diseases. It discusses how a defect in the immune system can trigger autoimmunity and lists examples of autoimmune disorders like rheumatoid arthritis, Graves' disease, and Hashimoto's thyroiditis. The causes of autoimmunity include genetic susceptibility and environmental triggers like infections. Viruses can induce autoimmunity through molecular mimicry or by damaging tissues and exposing new antigens.
Autoimmunity and autoimmune disorders
This document discusses autoimmunity and autoimmune diseases. It begins by defining autoimmunity as a breakdown of self-tolerance mechanisms that leads to an adaptive immune response against self-antigens. This can result in chronic inflammation and autoimmune disease. Several proposed mechanisms for how autoimmunity occurs are described, including defects in central and peripheral tolerance. Factors like genetics, hormones, infections, and environmental exposures are thought to contribute to loss of self-tolerance. The document then classifies and describes some examples of organ-specific and systemic autoimmune diseases in more detail.
Antigen processing & presentation
1. Antigen processing and presentation involves degradation of antigens into peptides, association of peptides with MHC molecules, and display of peptide-MHC complexes on the cell surface for recognition by T cells.
2. There are two main pathways of antigen processing - exogenous antigens that enter the cell are processed through the endocytic pathway while endogenous antigens are processed through the cytosolic pathway.
3. In the cytosolic pathway, antigens are degraded by the proteasome and transported by TAP into the ER where they can bind to MHC class I molecules. In the endocytic pathway, exogenous antigens internalized into vesicles are degraded into peptides that bind MHC class II molecules.
Cell-Mediated Immunity
Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. It is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
T and B cell activation
B-cell activation can occur through two routes - dependent or independent of T helper cells. T-helper cells interact with antigen-bound B-cells via CD40/CD40L and B7-CD28 costimulation, releasing cytokines that cause the B-cell to proliferate and differentiate into a plasma cell. The interaction of cytokines and proliferation factors released by T-helper cells provides signals needed for B-cell proliferation and class switching.
T-cell activation requires interaction between the TCR and antigen-bound MHC on an antigen presenting cell, as well as CD28-B7 costimulation, which causes cytokine release and leads to T-cell proliferation, clonal expansion, and differentiation into memory and
Immune tolerance
Immune tolerance refers to a state where an immune response is expected but does not occur. It is induced by prior exposure to an antigen during development of the immune system. Central tolerance occurs in the thymus and bone marrow where T and B cells that strongly react to self-antigens undergo deletion or anergy. This process ensures the immune system does not attack the body's own tissues.
T-cell activation
T-Cell Activation
• Concept of immune response
• T cell-mediated immune response
• B cell-mediated immune response
I. Concept of immune response
• A collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules in the immune system.
II. T cell-mediated immune response
• Cell-mediated immunity is the arm of the adaptive immune response whose role is to combat infection of intracellular pathogens, such as intracellular bacteria (mycobacteria, listeria monocytogens), viruses, protozoa, etc.
2. immune regulation
The document discusses various methods of immune regulation, including both immunosuppression and immunopotentiation. It describes several classes of immunosuppressive drugs like corticosteroids, thiopurines, alkylating agents, and monoclonal antibodies that can suppress the immune system. The document also discusses methods to potentiate the immune response through cytokines, adoptive immunotherapy, or vaccination. It outlines several immunological assays and techniques used to measure antibodies, cytokines, complement levels, and detect DNA sequences for diagnostic purposes.
Antigens ms
This document defines key immunological concepts such as antigens, immunogens, epitopes, haptens, cross-reactivity, mitogens, and superantigens. It explains that antigens are substances that induce an immune response, while immunogens are antigens that specifically induce an effective immune response. It also discusses the differences between B cell and T cell antigen recognition and factors that influence antigen immunogenicity.
Introduction to hypersensitive reactions
This document provides an overview of hypersensitive reactions and their classification. It discusses the five main types of hypersensitivity reactions: type I-IV reactions which are antibody-mediated and immediate (types I-III) or delayed (type IV); and type V which involves antibody stimulation of cell surface receptors. Type I is allergy mediated by IgE antibodies. Type II involves IgG/IgM binding to cell surfaces. Type III occurs via immune complex deposition. Type IV is cell-mediated via T cells. Examples of each type are given.
B- lymphocytes
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.
T-Cell Mediated Immunity
T cells are activated through the recognition of antigen peptides presented on MHC complexes on antigen presenting cells (APCs). This leads to T cell proliferation and differentiation into effector T cells. Cytotoxic T cells recognize endogenous antigens on MHC I to kill infected cells, while helper T cells recognize exogenous peptides on MHC II and secrete cytokines to stimulate macrophage activation or B cell antibody production. Full T cell activation requires both antigen recognition by the TCR and co-stimulatory signaling between molecules such as B7 and CD28.
Chapter 1 The Basic Immunology
The study in immunology provides the fundamental understanding of how the human body defend itself against foreign organisms, materials or particles that have the ability to cause harm to host tissues.
T cell development, maturation, activation and differentiation
T cell development, maturation, activation and differentiationKamaraj College of Engineering & Technology, Virudhunagar
This presentation is a part of Anna University B.Tech Biotechnology Semester 6 BT6602 Immunology syllabus Unit 2B-cell and humoral immunity
B-cells develop and mature in the bone marrow from stem cells through distinct stages marked by specific cell surface markers and patterns of immunoglobulin gene expression. Mature B-cells leave the bone marrow and travel to peripheral lymphoid tissues where they are activated upon encountering antigen to produce plasma cells that secrete antibodies and memory B-cells. B-cell activation involves proliferation, somatic hypermutation, selection, and potential class switching in germinal centers to produce high affinity antibodies and long-lasting immunological memory. This allows for a rapid secondary immune response upon re-exposure to the same antigen.
Autoimmunity
Autoimmunity disorders occur when the immune system mounts an attack against the body's own tissues and organs. They are difficult to diagnose due to nonspecific initial symptoms, fluctuating symptoms, and the potential for multiple autoimmune conditions. Diagnostic methods include initial laboratory tests of inflammatory markers and autoantibodies, immunological studies, flow cytometry to analyze immune cells, cytokine studies, and examination of major histocompatibility complex genes associated with autoimmunity. A variety of autoantibodies against nuclear, cytoplasmic, and other cellular components can indicate autoimmune disease patterns and targets.
Tolerance and autoimmunity
An undergraduate lecture on immunologic tolerance, it's various types and how a breakdown of tolerance contributes to the pathogenesis of autoimmune diseases. Additionally a small quiz at the end to gauge the students' learning.
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Autoimmunity and Tolerance
The document discusses immunological tolerance and its breakdown which can lead to autoimmunity and autoimmune diseases. It explains the mechanisms of central and peripheral tolerance that normally prevent immune responses against self-antigens. Failure of these tolerance mechanisms can occur through various causes like a breakdown of T cell anergy or loss of regulatory T cells, resulting in an immune response against self-tissues and the development of autoimmune conditions.
Autoimmunity
This document discusses immunological tolerance and autoimmunity. It defines central and peripheral tolerance as mechanisms by which the immune system learns to distinguish self from non-self. Central tolerance involves deletion of self-reactive lymphocytes in the thymus and bone marrow. Peripheral tolerance mechanisms include clonal deletion, anergy, and suppression. Failure of tolerance can lead to autoimmune diseases, which are influenced by genetic, hormonal, and environmental factors. Common triggers include molecular mimicry between microbial and self-antigens.
Adaptive immunity
The document discusses adaptive immunity and the specific immune response. It describes how adaptive immunity provides lifelong protective immunity through antigen-specific responses that are mediated by lymphocytes, including B cells, T cells, helper T cells, and killer T cells. Lymphocytes have antigen receptors like the B cell receptor and T cell receptor that provide specificity. The adaptive immune response develops over a person's lifetime through somatic recombination and clonal selection that generates a diverse repertoire of lymphocytes each with a unique receptor.
T CELL ACTIVATION AND IT'S TERMINATION
T cell activation requires two signals: 1) recognition of antigens displayed on antigen-presenting cells by T cell receptors and 2) co-stimulatory signals through molecules like CD28. This leads T cells to proliferate, differentiate into effector and memory cells, and perform effector functions. Proper activation requires interaction between T cells and antigen-presenting cells in lymphoid tissues, where costimulatory molecules are highly expressed. Dysregulation of T cell activation can lead to autoimmunity or susceptibility to infection.
Immunological tolerance
This document discusses immunological tolerance and regulatory T cells. It defines tolerance as unresponsiveness to antigen induced by previous exposure. Central tolerance occurs in the thymus through deletion of self-reactive T cells. Peripheral tolerance occurs through several mechanisms in tissues, including regulatory T cells that suppress immune responses. The key transcription factor controlling regulatory T cells is FOXP3. Mutations in FOXP3 can lead to immune dysregulation diseases like IPEX syndrome.
AUTOIMMUNITY
This document provides an overview of autoimmune diseases. It discusses how a defect in the immune system can trigger autoimmunity and lists examples of autoimmune disorders like rheumatoid arthritis, Graves' disease, and Hashimoto's thyroiditis. The causes of autoimmunity include genetic susceptibility and environmental triggers like infections. Viruses can induce autoimmunity through molecular mimicry or by damaging tissues and exposing new antigens.
Autoimmunity and autoimmune disorders
This document discusses autoimmunity and autoimmune diseases. It begins by defining autoimmunity as a breakdown of self-tolerance mechanisms that leads to an adaptive immune response against self-antigens. This can result in chronic inflammation and autoimmune disease. Several proposed mechanisms for how autoimmunity occurs are described, including defects in central and peripheral tolerance. Factors like genetics, hormones, infections, and environmental exposures are thought to contribute to loss of self-tolerance. The document then classifies and describes some examples of organ-specific and systemic autoimmune diseases in more detail.
Antigen processing & presentation
1. Antigen processing and presentation involves degradation of antigens into peptides, association of peptides with MHC molecules, and display of peptide-MHC complexes on the cell surface for recognition by T cells.
2. There are two main pathways of antigen processing - exogenous antigens that enter the cell are processed through the endocytic pathway while endogenous antigens are processed through the cytosolic pathway.
3. In the cytosolic pathway, antigens are degraded by the proteasome and transported by TAP into the ER where they can bind to MHC class I molecules. In the endocytic pathway, exogenous antigens internalized into vesicles are degraded into peptides that bind MHC class II molecules.
Cell-Mediated Immunity
Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. It is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
T and B cell activation
B-cell activation can occur through two routes - dependent or independent of T helper cells. T-helper cells interact with antigen-bound B-cells via CD40/CD40L and B7-CD28 costimulation, releasing cytokines that cause the B-cell to proliferate and differentiate into a plasma cell. The interaction of cytokines and proliferation factors released by T-helper cells provides signals needed for B-cell proliferation and class switching.
T-cell activation requires interaction between the TCR and antigen-bound MHC on an antigen presenting cell, as well as CD28-B7 costimulation, which causes cytokine release and leads to T-cell proliferation, clonal expansion, and differentiation into memory and
Immune tolerance
Immune tolerance refers to a state where an immune response is expected but does not occur. It is induced by prior exposure to an antigen during development of the immune system. Central tolerance occurs in the thymus and bone marrow where T and B cells that strongly react to self-antigens undergo deletion or anergy. This process ensures the immune system does not attack the body's own tissues.
T-cell activation
T-Cell Activation
• Concept of immune response
• T cell-mediated immune response
• B cell-mediated immune response
I. Concept of immune response
• A collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules in the immune system.
II. T cell-mediated immune response
• Cell-mediated immunity is the arm of the adaptive immune response whose role is to combat infection of intracellular pathogens, such as intracellular bacteria (mycobacteria, listeria monocytogens), viruses, protozoa, etc.
2. immune regulation
The document discusses various methods of immune regulation, including both immunosuppression and immunopotentiation. It describes several classes of immunosuppressive drugs like corticosteroids, thiopurines, alkylating agents, and monoclonal antibodies that can suppress the immune system. The document also discusses methods to potentiate the immune response through cytokines, adoptive immunotherapy, or vaccination. It outlines several immunological assays and techniques used to measure antibodies, cytokines, complement levels, and detect DNA sequences for diagnostic purposes.
Antigens ms
This document defines key immunological concepts such as antigens, immunogens, epitopes, haptens, cross-reactivity, mitogens, and superantigens. It explains that antigens are substances that induce an immune response, while immunogens are antigens that specifically induce an effective immune response. It also discusses the differences between B cell and T cell antigen recognition and factors that influence antigen immunogenicity.
Introduction to hypersensitive reactions
This document provides an overview of hypersensitive reactions and their classification. It discusses the five main types of hypersensitivity reactions: type I-IV reactions which are antibody-mediated and immediate (types I-III) or delayed (type IV); and type V which involves antibody stimulation of cell surface receptors. Type I is allergy mediated by IgE antibodies. Type II involves IgG/IgM binding to cell surfaces. Type III occurs via immune complex deposition. Type IV is cell-mediated via T cells. Examples of each type are given.
B- lymphocytes
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.
T-Cell Mediated Immunity
T cells are activated through the recognition of antigen peptides presented on MHC complexes on antigen presenting cells (APCs). This leads to T cell proliferation and differentiation into effector T cells. Cytotoxic T cells recognize endogenous antigens on MHC I to kill infected cells, while helper T cells recognize exogenous peptides on MHC II and secrete cytokines to stimulate macrophage activation or B cell antibody production. Full T cell activation requires both antigen recognition by the TCR and co-stimulatory signaling between molecules such as B7 and CD28.
Chapter 1 The Basic Immunology
The study in immunology provides the fundamental understanding of how the human body defend itself against foreign organisms, materials or particles that have the ability to cause harm to host tissues.
T cell development, maturation, activation and differentiation
T cell development, maturation, activation and differentiationKamaraj College of Engineering & Technology, Virudhunagar
This presentation is a part of Anna University B.Tech Biotechnology Semester 6 BT6602 Immunology syllabus Unit 2B-cell and humoral immunity
B-cells develop and mature in the bone marrow from stem cells through distinct stages marked by specific cell surface markers and patterns of immunoglobulin gene expression. Mature B-cells leave the bone marrow and travel to peripheral lymphoid tissues where they are activated upon encountering antigen to produce plasma cells that secrete antibodies and memory B-cells. B-cell activation involves proliferation, somatic hypermutation, selection, and potential class switching in germinal centers to produce high affinity antibodies and long-lasting immunological memory. This allows for a rapid secondary immune response upon re-exposure to the same antigen.
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Autoimmunity
Autoimmunity disorders occur when the immune system mounts an attack against the body's own tissues and organs. They are difficult to diagnose due to nonspecific initial symptoms, fluctuating symptoms, and the potential for multiple autoimmune conditions. Diagnostic methods include initial laboratory tests of inflammatory markers and autoantibodies, immunological studies, flow cytometry to analyze immune cells, cytokine studies, and examination of major histocompatibility complex genes associated with autoimmunity. A variety of autoantibodies against nuclear, cytoplasmic, and other cellular components can indicate autoimmune disease patterns and targets.
Tolerance and autoimmunity
An undergraduate lecture on immunologic tolerance, it's various types and how a breakdown of tolerance contributes to the pathogenesis of autoimmune diseases. Additionally a small quiz at the end to gauge the students' learning.
Immune tolerance
Immune tolerance, or immunological tolerance, or immunotolerance, is a state of unresponsiveness of the immune system to substances or tissue that have the capacity to elicit an immune response in a given organism. Immune tolerance is important for normal physiology. Central tolerance is the main way the immune system learns to discriminate self from non-self. Peripheral tolerance is key to preventing over-reactivity of the immune system to various environmental entities (allergens, gut microbes, etc.).
Principles of tolerance and autoimmune diseases
This document discusses principles of immunological tolerance and autoimmunity. It describes how central tolerance in the thymus and bone marrow eliminates self-reactive immune cells, while peripheral tolerance mechanisms like T cell anergy, activation-induced cell death, and regulatory T cells control immune responses in tissues. Failure of these tolerance mechanisms can lead to autoimmunity when immune cells attack the body's own tissues and organs. Certain genetic factors like HLA alleles are also associated with increased risk of autoimmune diseases. The roles of infection in potentially triggering autoimmunity through molecular mimicry are also mentioned.
The adaptive immunity and its features..
The adaptive immune system provides tailored and specific responses to pathogens through lymphocytes like T and B cells. It overcomes limitations of innate immunity by being non-specific, having poor regulation and amplification, and lacking self-discrimination. The adaptive response recognizes specific antigens through antigen receptors on lymphocytes. This leads to clonal expansion of effector and memory cells that provide rapid responses upon re-exposure. Adaptive immunity involves cell-mediated responses by T cells and humoral responses by antibody-producing B cells. It provides immunological memory for long-term protection against pathogens.
Tolerance of immune system.pptx
Central and peripheral tolerance are mechanisms that establish immunological tolerance to self-antigens. Central tolerance involves deletion of self-reactive T and B cells in the thymus and bone marrow during maturation. Peripheral tolerance uses additional mechanisms like clonal deletion, clonal anergy, and suppression to silence self-reactive cells that escape central tolerance. Failure of tolerance mechanisms can lead to autoimmune diseases where the immune system attacks the body's own tissues.
Basic Features of Autoimmune Diseases
This document provides an overview of autoimmune diseases and immunologic tolerance. It discusses several key points:
- Autoimmune diseases result from immune reactions against self antigens and can affect connective tissues/blood vessels.
- Normal tolerance to self antigens occurs through central tolerance in the thymus and bone marrow and peripheral tolerance in tissues.
- Breakdown of tolerance and autoimmunity are caused by genetic susceptibility and environmental triggers that alter self antigen display/responses.
- Many autoimmune diseases are associated with specific HLA alleles, though they generally have complex, multigenic inheritance.
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The document discusses the characteristics and components of adaptive immunity. There are two main types: humoral immunity mediated by antibodies produced by B cells, and cellular immunity mediated by T cells. Humoral immunity responds to extracellular pathogens by generating antibodies that bind to antigens, while cellular immunity utilizes T cells to identify and destroy infected cells. The adaptive immune system has memory and can mount faster responses upon reexposure to pathogens.
Adaptive immunity
The document summarizes key principles of the adaptive immune response. It describes how adaptive immunity arose due to limitations of innate immunity, including lack of specificity and memory. The adaptive response involves T and B lymphocytes that recognize specific antigens through cell surface receptors. Activation of T and B cells requires recognition of antigen along with costimulatory signals. This leads to clonal expansion and generation of effector cells and immunological memory. Adaptive immunity allows for tailored, amplified responses with self/non-self discrimination and immunological memory.
Antigen.pptx
Antigen is any substance that induces an immune response in the body. There are two main types: complete antigens that can induce an immune response on their own, and incomplete antigens or haptens that require a carrier molecule to become immunogenic. Antigens are recognized by immune cells through antigen determinants or epitopes. For a response, antigens must be processed and presented by antigen-presenting cells to be recognized by T cells through MHC molecules. The properties of an antigen like its size, structure, and route of administration influence its ability to induce an immune response.
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The document provides an overview of the immune system, including:
1. It differentiates between innate and adaptive immunity and describes cells involved in each.
2. It outlines the properties of adaptive immunity including specificity and memory.
3. It describes the tissues and organs of the immune system including peripheral lymphoid organs and lymphocyte circulation.
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The document summarizes the key components of the humoral and cell-mediated immune response. It describes the nonspecific first and second lines of defense, including physical and chemical barriers. The third line of specific defense involves humoral immunity mediated by B cells and antibodies, and cell-mediated immunity carried out by T cells. It details the roles of helper T cells, cytotoxic T cells, B cells, plasma cells, and memory cells in the adaptive immune response during primary and secondary infections.
Immunulogy
The document discusses the immune system, including both innate and adaptive immunity. It provides details on the components and functions of the innate immune system, such as physical barriers, white blood cells, and cytokines. Adaptive immunity involves lymphocytes and develops a specific response along with memory. The adaptive response includes both humoral immunity carried out by B cells and antibodies, as well as cell-mediated immunity involving T cells. Key aspects covered are antigen presentation, roles of T cell subsets, and the relationship between the humoral and cell-mediated responses.
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Antigens, haptens and immunogens were discussed. Key points:
- Antigens are molecules that induce an immune response through binding antibodies or T cells. Immunogens can induce immune responses while antigens may only bind antibodies/T cells.
- Antigens are classified based on origin (exogenous, endogenous, autoantigens), chemical structure (proteins, polysaccharides etc.), and type of immune response generated (T cell dependent/independent).
- Immunogenicity depends on antigen properties like size, structure and degradability as well as the exposed biological system. Larger complex molecules tend to be more immunogenic.
Immunology Tolerance.ppt
This document discusses immunological tolerance, including:
- Tolerance is a state of unresponsiveness to a specific antigen induced by prior exposure. It prevents immune attacks on self-tissues.
- Tolerance can be induced centrally in the thymus and bone marrow or peripherally everywhere in the body, through mechanisms like clonal deletion, anergy, and suppression.
- The induction of tolerance depends on factors like the differentiation stage of lymphocytes, the site of antigen encounter, and the microenvironment. Both active and passive forms of tolerance exist.
Adaptive immunity - 2023.pptx
Adaptive immunity can be acquired naturally through infection or artificially through immunoglobulin injection or vaccination. It involves two main mechanisms: humoral immunity mediated by antibodies produced by B lymphocytes, and cell-mediated immunity mediated by T lymphocytes. Adaptive immunity is characterized by antigen specificity, diversity, immunological memory, self/non-self discrimination, and anamnestic responses. B and T lymphocytes develop and mature in the bone marrow and thymus, respectively, undergoing selection processes to respond appropriately to pathogens.
Immunological tolerance and resistance
Immunological tolerance occurs when the immune system does not attack the body's own tissues. Central tolerance occurs during lymphocyte development and eliminates self-reactive cells. Peripheral tolerance maintains tolerance after lymphocytes leave the primary organs. Mechanisms of central tolerance include deletion of self-reactive T and B cells in the thymus and bone marrow. Peripheral tolerance prevents autoimmunity through deletion, anergy, and ignorance of self-reactive cells in secondary lymphoid tissues. Immunological tolerance is crucial for distinguishing self from non-self and preventing autoimmune disease.
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Humoral and cell mediated immunity, Educational Platform.pptx
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Deep Software Variability and Frictionless Reproducibility
Deep Software Variability and Frictionless ReproducibilityUniversity of Rennes, INSA Rennes, Inria/IRISA, CNRS
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
waterlessdyeingtechnolgyusing carbon dioxide chemicalspdf
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/Equivariant neural networks and representation theory
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
Thornton ESPP slides UK WW Network 4_6_24.pdf
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)”
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Current descriptions of immersive learning cases are often difficult or impossible to compare. This is due to a myriad of different options on what details to include, which aspects are relevant, and on the descriptive approaches employed. Also, these aspects often combine very specific details with more general guidelines or indicate intents and rationales without clarifying their implementation. In this paper we provide a method to describe immersive learning cases that is structured to enable comparisons, yet flexible enough to allow researchers and practitioners to decide which aspects to include. This method leverages a taxonomy that classifies educational aspects at three levels (uses, practices, and strategies) and then utilizes two frameworks, the Immersive Learning Brain and the Immersion Cube, to enable a structured description and interpretation of immersive learning cases. The method is then demonstrated on a published immersive learning case on training for wind turbine maintenance using virtual reality. Applying the method results in a structured artifact, the Immersive Learning Case Sheet, that tags the case with its proximal uses, practices, and strategies, and refines the free text case description to ensure that matching details are included. This contribution is thus a case description method in support of future comparative research of immersive learning cases. We then discuss how the resulting description and interpretation can be leveraged to change immersion learning cases, by enriching them (considering low-effort changes or additions) or innovating (exploring more challenging avenues of transformation). The method holds significant promise to support better-grounded research in immersive learning.
20240520 Planning a Circuit Simulator in JavaScript.pptx
Evaporation step counter work. I have done a physical experiment.
(Work in progress.)
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留信网认证的作用:
1:该专业认证可证明留学生真实身份
2:同时对留学生所学专业登记给予评定
3:国家专业人才认证中心颁发入库证书
4:这个认证书并且可以归档倒地方
5:凡事获得留信网入网的信息将会逐步更新到个人身份内，将在公安局网内查询个人身份证信息后，同步读取人才网入库信息
6:个人职称评审加20分
7:个人信誉贷款加10分
8:在国家人才网主办的国家网络招聘大会中纳入资料，供国家高端企业选择人才
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
bordetella pertussis.................................ppt
Bordettela is a gram negative cocobacilli spread by air born drop let
ESR spectroscopy in liquid food and beverages.pptx
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.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...
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.
The binding of cosmological structures by massless topological defects
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.
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...Abdul Wali Khan University Mardan,kP,Pakistan
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skillsApplied Science: Thermodynamics, Laws & Methodology.pdf
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
Authoring a personal GPT for your research and practice: How we created the Q...
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Recently uploaded (20)
aziz sancar nobel prize winner: from mardin to nobel
aziz sancar nobel prize winner: from mardin to nobel
Deep Software Variability and Frictionless Reproducibility
Deep Software Variability and Frictionless Reproducibility
waterlessdyeingtechnolgyusing carbon dioxide chemicalspdf
waterlessdyeingtechnolgyusing carbon dioxide chemicalspdf
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...
Equivariant neural networks and representation theory
Equivariant neural networks and representation theory
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
Describing and Interpreting an Immersive Learning Case with the Immersion Cub...
20240520 Planning a Circuit Simulator in JavaScript.pptx
20240520 Planning a Circuit Simulator in JavaScript.pptx
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
bordetella pertussis.................................ppt
bordetella pertussis.................................ppt
ESR spectroscopy in liquid food and beverages.pptx
ESR spectroscopy in liquid food and beverages.pptx
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...
THEMATIC APPERCEPTION TEST(TAT) cognitive abilities, creativity, and critic...
Applied Science: Thermodynamics, Laws & Methodology.pdf
Applied Science: Thermodynamics, Laws & Methodology.pdf
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
Immunological tolerance
- 2. Antigen • Recognized by immune system • Substance that induces immune response in a body • Can be foreign or self
- 3. Foreign antigen Not part of our body Self antigen Components of our own body
- 4. First line of defense Skin and mucous membrane Second line of defense Defensive cells, Antimicrobial substances, Inflammation, fever Third line of defense T cells, B cells, Antigen presenting cells Foreign Antigen
- 5. BCR TCR Our immune system can generate lymphocytes clones that can virtually recognize any antigen in universe.
- 6. Self antigen Components of our own body Lymphocytes having receptors against self antigens are constantly being generated in our body. Auto-reactive (self-reactive) Lymphocytes How we avoid attack on our own cells and tissues?
- 7. Our immune system has ability to react with enormous and diverse foreign antigens While it is tolerant to self antigen The state of unresponsiveness of the immune system to antigens is known as immunological tolerance The state of unresponsiveness of the immune system to antigens is known as Self tolerance
- 8. Self-Tolerance Achieved by various mechanisms and processes operating on the cell of immune system 1. Central Tolerance • Central refers to primary or central lymphoid organs • T and B lymphocytes first express antigen receptors • Comprises of mechanisms that eliminate most auto-reactive T and B cells during their early development 2. Peripheral Tolerance • Peripheral refers to the secondary or peripheral lymphoid organs • Tolerance induced in mature lymphocytes • Prevent auto-reactive mature lymphocytes from attacking self antigen
- 9. Central T Cell Tolerance Inside Thymus Immature T-cell undergo an elaborate screening process Non-Selection Negative Selection Positive Selection
- 10. Inside Thymus Immature T cell Self peptide: Self MHC molecule Fate of developing T cell depends on…. The strength with which immature T cells interact with Self peptide: Self MHC molecules
- 11. No interaction Apoptosis (of T cells) • Non-functional TCRs • Lack receptors recognizing MHC molecules Non-selection
- 12. Moderate interaction Survival (of T cells) • Interaction is not too strong nor too weak • T cells learn to focus on self-MHC molecules (MHC restriction) Positive selection
- 13. Strong interaction Apoptosis (of T cells) • Potentially auto-reactive cells • Dead cells are phagocytosed by macrophages in the thymus Negative selection
- 14. Peripheral T cell Tolerance Mechanisms: • Peripheral clonal deletion • Anergy • Immune deviation • Immune privilege • Immunosuppressive cytokines • Regulatory T cells Prevent T cell activation Control Immune responses
- 15. Self antigen Danger signals are absent • Co-stimulatory molecules are not expressed. • T cell receives first signal for its activation • No second signal- because co- stimulatory molecules on DCs are absent Peripheral clonal deletion of T cells
- 16. Anergy Some auto-reactive T cells survive But remain INACTIVATED
- 17. What if auto reactive T cells get activated? Other control mechanisms Immune Deviation Potentially harmful immune response is converted into less harmful immune response Regulatory T cells Control the responses of activated T cells Immune privilege Anatomical regions that are less subject to immune responses Immunosuppressive Cytokines IL-10 TGF-β Immunosuppressive effects
- 18. Central B Cell Tolerance Inside Bone marrow Central B cell tolerance uses 3 mechanisms to induce tolerance: Receptor Editing Clonal Deletion Anergy
- 19. Receptor Editing Antigen receptor of autoreactive immature B cell is MODIFIED Immature B cells have ability to rearrange their immunoglobulin genes. Light chain locus
- 20. Receptor Editing Strong cross linking of BCRs and multivalent cells rearranging immunoglobulin genes in the light chain loci Old chain is replaced by new light chain Non self-reactiveSelf-reactive B cell development continues and mature B cell migrate to periphery Apoptosis Clonal Deletion
- 21. Inside Bone marrow B cells become unresponsive Monovalent antigens Interaction with B cells Anergy Monovalent antigens are also present in the bone marrow Anergic cells enter peripheral circulation
- 22. Peripheral B Cell Tolerance Auto-reactive B cell Self antigen B cell becomes unresponsive Absence of signals • B cell requires T cell help for activation • But auto-reactive T cells are eliminated by Central Tolerance • Without T cell help, there is no signals for auto- reactive B cell activation
- 23. Thank you