The document discusses antigens, immunogens, and the major histocompatibility complex (MHC). It describes how antigens are recognized by antibodies or T cell receptors, with immunogens being antigens that can trigger an immune response. The ability of immunogens to stimulate the immune system depends on their nature and genetic coding of MHC, which combines with immunogens for T cell recognition. MHC molecules present antigen peptides and are encoded by genes that confer the ability to mount immune responses.
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.
This document provides information on MHC class I and class II molecules, including their structure, function, and role in antigen presentation. It discusses that MHC class I molecules are expressed on all nucleated cells and present intracellular antigens to CD8+ T cells. MHC class II molecules are expressed primarily on antigen presenting cells and present extracellular antigens to CD4+ T cells. The peptide binding grooves of MHC class I and II molecules differ in their structure and the size of peptides they can bind.
The Major Histocompatibility Complex (MHC):
- Is located on chromosome 6 and contains genes such as HLA that play a role in distinguishing self from non-self.
- Genes are organized into three classes: class I present antigens to T cells, class II present antigens to T helper cells, and class III genes produce immune system proteins.
- MHC molecules are highly polymorphic and inherited as sets (haplotypes) from each parent, allowing presentation of a wide variety of antigens.
Antigen processing and presentation involves two pathways: 1) Exogenous antigens are internalized, processed in the endosome, and presented on MHC class II to CD4+ T cells. 2) Endogenous antigens are processed by the proteasome in the cytosol, transported to the ER by TAP, loaded onto MHC class I, and presented to CD8+ T cells. For an immune response, antigen must be degraded into peptides and bound to MHC molecules on antigen presenting cells to activate T cells through TCR recognition and co-stimulation.
This document summarizes various antigen-antibody interaction techniques including: precipitation reactions, agglutination reactions, radioimmunoassay, enzyme-linked immunosorbent assay, Western blotting, immunoprecipitation, immunofluorescence, flow cytometry, and alternatives like protein A/G and biotin-avidin interactions. It describes how each technique detects and analyzes the binding between antigens and antibodies through measurements, visualizations, or separations based on properties like molecular weight, charge, or fluorescent labeling.
The document summarizes key concepts about the major histocompatibility complex (MHC):
1) The MHC was discovered through studies of transplant rejection in mice, which showed that rejection was dependent on the genetics of the donor and recipient strains.
2) MHC molecules present peptide antigens to T cells and play a key role in immune responses, including transplant rejection.
3) MHC molecules are highly polymorphic, with many variants within populations, in order to allow populations to recognize a wide variety of pathogens.
This document provides a summary of a credit seminar on the major histocompatibility complex (MHC). The seminar covered the introduction, definition, history, classes of MHC, differences between MHC class I and II, and MHC in animals. MHC plays an important role in distinguishing self from non-self and antigen presentation. There are three classes of MHC - class I presents antigens to cytotoxic T cells, class II presents antigens to helper T cells, and class III encodes immune system proteins. MHC genes are highly polymorphic and influence disease resistance in various animal species.
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.
This document provides information on MHC class I and class II molecules, including their structure, function, and role in antigen presentation. It discusses that MHC class I molecules are expressed on all nucleated cells and present intracellular antigens to CD8+ T cells. MHC class II molecules are expressed primarily on antigen presenting cells and present extracellular antigens to CD4+ T cells. The peptide binding grooves of MHC class I and II molecules differ in their structure and the size of peptides they can bind.
The Major Histocompatibility Complex (MHC):
- Is located on chromosome 6 and contains genes such as HLA that play a role in distinguishing self from non-self.
- Genes are organized into three classes: class I present antigens to T cells, class II present antigens to T helper cells, and class III genes produce immune system proteins.
- MHC molecules are highly polymorphic and inherited as sets (haplotypes) from each parent, allowing presentation of a wide variety of antigens.
Antigen processing and presentation involves two pathways: 1) Exogenous antigens are internalized, processed in the endosome, and presented on MHC class II to CD4+ T cells. 2) Endogenous antigens are processed by the proteasome in the cytosol, transported to the ER by TAP, loaded onto MHC class I, and presented to CD8+ T cells. For an immune response, antigen must be degraded into peptides and bound to MHC molecules on antigen presenting cells to activate T cells through TCR recognition and co-stimulation.
This document summarizes various antigen-antibody interaction techniques including: precipitation reactions, agglutination reactions, radioimmunoassay, enzyme-linked immunosorbent assay, Western blotting, immunoprecipitation, immunofluorescence, flow cytometry, and alternatives like protein A/G and biotin-avidin interactions. It describes how each technique detects and analyzes the binding between antigens and antibodies through measurements, visualizations, or separations based on properties like molecular weight, charge, or fluorescent labeling.
The document summarizes key concepts about the major histocompatibility complex (MHC):
1) The MHC was discovered through studies of transplant rejection in mice, which showed that rejection was dependent on the genetics of the donor and recipient strains.
2) MHC molecules present peptide antigens to T cells and play a key role in immune responses, including transplant rejection.
3) MHC molecules are highly polymorphic, with many variants within populations, in order to allow populations to recognize a wide variety of pathogens.
This document provides a summary of a credit seminar on the major histocompatibility complex (MHC). The seminar covered the introduction, definition, history, classes of MHC, differences between MHC class I and II, and MHC in animals. MHC plays an important role in distinguishing self from non-self and antigen presentation. There are three classes of MHC - class I presents antigens to cytotoxic T cells, class II presents antigens to helper T cells, and class III encodes immune system proteins. MHC genes are highly polymorphic and influence disease resistance in various animal species.
The document provides an overview of major histocompatibility complex (MHC) and human leukocyte antigen (HLA) typing. It discusses that MHC molecules present antigen fragments to T cells and are classified into classes I, II, and III. MHC proteins in humans are called HLA genes and are located on chromosome 6. The document describes HLA classification, functions in infectious disease, graft rejection, and autoimmunity, as well as genetics and methods of HLA typing including serotyping, phenotyping, and allele names.
This presentation clearly describes what are immunoglobulins, their types, structure and how they get diversified into different isotopes to fight with foreign antigens.
The document discusses various properties of antigens that determine their antigenicity including molecular size, foreignness, chemical complexity, stability, and more. It also describes different types of antigenic determinants recognized by B cells and T cells as well as factors like dosage, route of administration, and adjuvants that influence immunogenicity. Finally, it covers antigen specificity and different types of antigens such as haptens, superantigens, and isoantigens.
Immunoglobulins, also known as antibodies, are Y-shaped glycoproteins produced by plasma cells that function to identify and neutralize foreign objects like bacteria and viruses. Each arm of the Y contains a paratope that binds to a specific epitope on an antigen. There are five classes of immunoglobulins - IgG, IgM, IgA, IgD, and IgE - which differ in their structure and functions like complement fixation, binding to cells, and roles in allergic reactions and parasitic infections. Multiple myeloma is a plasma cell tumor characterized by overproduction of IgG and IgM antibodies and Bence Jones proteins in the serum and urine.
This document provides an overview of immunity and the immune system. It defines different types of immunity, including innate immunity, acquired (adaptive) immunity, humoral immunity, and cell-mediated immunity. It describes the roles of lymphocytes (T cells and B cells) and antibodies in acquired immunity. It also explains antigen presentation, activation of lymphocytes, primary and secondary immune responses, and the mechanisms of humoral and cell-mediated immunity. Finally, it discusses the complement system and its role in opsonization, lysis, agglutination, and other immune functions.
Haptens are small molecules that are antigenic but not immunogenic on their own. They are unable to induce an immune response because they cannot activate helper T cells due to their inability to bind MHC proteins or activate B cells directly as they are univalent. However, when haptens are covalently bound to a carrier protein, they form immunogenic conjugates that can induce an immune response by activating helper T cells and B cells. Pioneering work by Karl Landsteiner demonstrated that antibodies produced against hapten-carrier conjugates were specific for the hapten and carrier epitopes. Common examples of haptens include drug molecules, peptides, and steroids. Hapten-protein conjugates can cause drug
Adaptive immunity is an immunity that occurs after exposure to an antigen either from a pathogen or a vaccination. This part of the immune system is activated when the innate immune response is insufficient to control an infection. In fact, without information from the innate immune system, the adaptive response could not be mobilized. There are two types of adaptive responses: the cell-mediated immune response, which is carried out by T cells, and the humoral immune response, which is controlled by activated B cells and antibodies.
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
ANTIGEN, HAPTEN, ALL TYPES OF ANTIGENS, IMMUNOGEN , ATTRIBUTES OF ANTIGENICITY, DETERMINANTS OF ANTIGENICITY,
IMMUNOLOGY KUBY, MEDICAL MICROBIOLOGY & IMMUNOLOGY OF PANIKER , LIPPINCOTT'S IMMUNOLOGY, OTHER SOURCES.
Polyclonal antibodies are produced by injecting an antigen into a host animal which causes its immune system to produce various antibodies that recognize different epitopes of the antigen. The antibodies are then purified from the animal's blood plasma. Polyclonal antibodies are a heterogeneous mixture that can bind to multiple epitopes of the same antigen, whereas monoclonal antibodies are all clones that recognize the same epitope.
1. The major histocompatibility complex (MHC) helps the immune system recognize foreign substances. It is expressed on nearly all cells and plays a crucial role in organ transplant compatibility.
2. MHC molecules are classified into three types - MHC class I presents antigens to T cells within cells, MHC class II presents antigens to T cells between cells, and MHC class III encodes proteins unrelated to antigen presentation.
3. Antigens are processed through two pathways - the cytosolic pathway for endogenous antigens and the endocytic pathway for exogenous antigens - and bound to MHC molecules for presentation to T cells, which triggers an immune response against foreign or transplanted tissues that do not match the recipient's MHC.
Major Histocompatibility complex & Antigen Presentation and ProcessingSreeraj Thamban
The document discusses the major histocompatibility complex (MHC) and antigen processing and presentation. It describes MHC molecules as polymorphic glycoproteins that play a role in discriminating self from non-self and participate in both humoral and cell-mediated immunity. MHC class I molecules present endogenous antigens on most nucleated cells and interact with CD8+ T cells. MHC class II molecules present exogenous antigens on antigen-presenting cells and interact with CD4+ T cells. Antigens are processed into peptides of appropriate size and bound motifs to be presented in the binding groove of MHC molecules.
1. The MHC molecules present peptide antigens to T cells. Class I MHC present intracellular peptides to CD8+ T cells, while class II MHC present extracellular peptides taken up by endocytosis to CD4+ T cells.
2. Antigens are processed through different pathways depending on if they are intracellular or extracellular. Intracellular antigens are degraded by the proteasome and transported into the ER by TAP to bind class I MHC. Extracellular antigens are endocytosed and degraded in lysosomes to bind class II MHC.
3. The peptide-MHC complexes are then transported to the cell surface for recognition by T cell receptors.
Antigens are substances that stimulate the immune system to produce antibodies against them. They enter the body through various sites and are then captured and presented by antigen presenting cells. There are several types of antigens including immunogens, which induce immune responses; tolerogens, which induce tolerance; allergens; and vaccines. An antigen's ability to induce an immune response is called its immunogenicity, while its ability to bind antibodies is its antigenicity. Properties that influence immunogenicity include the antigen's foreignness, size, complexity, degradability, and the recipient's genotype and age. Administration methods like dosage, route, and use of adjuvants can also impact immunogenicity. Antigens are classified as complete if they have
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.
The document summarizes the key mechanisms by which the human immune system generates a diverse repertoire of antibodies from a relatively small number of genes. It describes the somatic variation theory where mutation and recombination of immunoglobulin genes in somatic cells results in high antibody diversity. It explains processes like V(D)J recombination of light and heavy chain genes, junctional diversity, allelic exclusion, somatic hypermutation, and class switching which all contribute to antibody diversity.
1. An immunogen is an agent capable of inducing an immune response, while an antigen is any agent capable of binding to components of the immune system. All immunogens are antigens, but not all antigens are immunogens.
2. Haptens are low molecular weight compounds that are incapable of inducing an immune response alone but can do so when conjugated to a carrier molecule like a protein.
3. For a substance to be immunogenic, it must be foreign, have a high molecular weight and chemical complexity, be degradable, and interact with MHC molecules.
Transplantation involves transferring organs, tissues or cells from one part of the body to another or between individuals. Compatibility of immune molecules like HLA antigens, ABO blood groups, MIC antigens and KIR determines transplant success. Major histocompatibility complex (MHC) molecules control immune response and are targets in transplant rejection. Incompatibility can lead to hyperacute, acute cellular or chronic rejection as well as graft-versus-host disease. Immunosuppressive agents like corticosteroids, calcineurin inhibitors and monoclonal antibodies are used to suppress anti-graft immune responses.
An antigen is any substance that reacts with lymphocytes, while immunogens generate immune responses. Haptens are small molecules that require coupling to carriers to induce responses. Antibody-antigen binding depends on weak interactions between sites on antibodies and epitopes on antigens. Antibodies are produced with a wide variety of binding sites to recognize different antigenic determinants. Factors like foreignness, size, structure, and route of administration influence a substance's immunogenicity.
The document provides an overview of major histocompatibility complex (MHC) and human leukocyte antigen (HLA) typing. It discusses that MHC molecules present antigen fragments to T cells and are classified into classes I, II, and III. MHC proteins in humans are called HLA genes and are located on chromosome 6. The document describes HLA classification, functions in infectious disease, graft rejection, and autoimmunity, as well as genetics and methods of HLA typing including serotyping, phenotyping, and allele names.
This presentation clearly describes what are immunoglobulins, their types, structure and how they get diversified into different isotopes to fight with foreign antigens.
The document discusses various properties of antigens that determine their antigenicity including molecular size, foreignness, chemical complexity, stability, and more. It also describes different types of antigenic determinants recognized by B cells and T cells as well as factors like dosage, route of administration, and adjuvants that influence immunogenicity. Finally, it covers antigen specificity and different types of antigens such as haptens, superantigens, and isoantigens.
Immunoglobulins, also known as antibodies, are Y-shaped glycoproteins produced by plasma cells that function to identify and neutralize foreign objects like bacteria and viruses. Each arm of the Y contains a paratope that binds to a specific epitope on an antigen. There are five classes of immunoglobulins - IgG, IgM, IgA, IgD, and IgE - which differ in their structure and functions like complement fixation, binding to cells, and roles in allergic reactions and parasitic infections. Multiple myeloma is a plasma cell tumor characterized by overproduction of IgG and IgM antibodies and Bence Jones proteins in the serum and urine.
This document provides an overview of immunity and the immune system. It defines different types of immunity, including innate immunity, acquired (adaptive) immunity, humoral immunity, and cell-mediated immunity. It describes the roles of lymphocytes (T cells and B cells) and antibodies in acquired immunity. It also explains antigen presentation, activation of lymphocytes, primary and secondary immune responses, and the mechanisms of humoral and cell-mediated immunity. Finally, it discusses the complement system and its role in opsonization, lysis, agglutination, and other immune functions.
Haptens are small molecules that are antigenic but not immunogenic on their own. They are unable to induce an immune response because they cannot activate helper T cells due to their inability to bind MHC proteins or activate B cells directly as they are univalent. However, when haptens are covalently bound to a carrier protein, they form immunogenic conjugates that can induce an immune response by activating helper T cells and B cells. Pioneering work by Karl Landsteiner demonstrated that antibodies produced against hapten-carrier conjugates were specific for the hapten and carrier epitopes. Common examples of haptens include drug molecules, peptides, and steroids. Hapten-protein conjugates can cause drug
Adaptive immunity is an immunity that occurs after exposure to an antigen either from a pathogen or a vaccination. This part of the immune system is activated when the innate immune response is insufficient to control an infection. In fact, without information from the innate immune system, the adaptive response could not be mobilized. There are two types of adaptive responses: the cell-mediated immune response, which is carried out by T cells, and the humoral immune response, which is controlled by activated B cells and antibodies.
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
ANTIGEN, HAPTEN, ALL TYPES OF ANTIGENS, IMMUNOGEN , ATTRIBUTES OF ANTIGENICITY, DETERMINANTS OF ANTIGENICITY,
IMMUNOLOGY KUBY, MEDICAL MICROBIOLOGY & IMMUNOLOGY OF PANIKER , LIPPINCOTT'S IMMUNOLOGY, OTHER SOURCES.
Polyclonal antibodies are produced by injecting an antigen into a host animal which causes its immune system to produce various antibodies that recognize different epitopes of the antigen. The antibodies are then purified from the animal's blood plasma. Polyclonal antibodies are a heterogeneous mixture that can bind to multiple epitopes of the same antigen, whereas monoclonal antibodies are all clones that recognize the same epitope.
1. The major histocompatibility complex (MHC) helps the immune system recognize foreign substances. It is expressed on nearly all cells and plays a crucial role in organ transplant compatibility.
2. MHC molecules are classified into three types - MHC class I presents antigens to T cells within cells, MHC class II presents antigens to T cells between cells, and MHC class III encodes proteins unrelated to antigen presentation.
3. Antigens are processed through two pathways - the cytosolic pathway for endogenous antigens and the endocytic pathway for exogenous antigens - and bound to MHC molecules for presentation to T cells, which triggers an immune response against foreign or transplanted tissues that do not match the recipient's MHC.
Major Histocompatibility complex & Antigen Presentation and ProcessingSreeraj Thamban
The document discusses the major histocompatibility complex (MHC) and antigen processing and presentation. It describes MHC molecules as polymorphic glycoproteins that play a role in discriminating self from non-self and participate in both humoral and cell-mediated immunity. MHC class I molecules present endogenous antigens on most nucleated cells and interact with CD8+ T cells. MHC class II molecules present exogenous antigens on antigen-presenting cells and interact with CD4+ T cells. Antigens are processed into peptides of appropriate size and bound motifs to be presented in the binding groove of MHC molecules.
1. The MHC molecules present peptide antigens to T cells. Class I MHC present intracellular peptides to CD8+ T cells, while class II MHC present extracellular peptides taken up by endocytosis to CD4+ T cells.
2. Antigens are processed through different pathways depending on if they are intracellular or extracellular. Intracellular antigens are degraded by the proteasome and transported into the ER by TAP to bind class I MHC. Extracellular antigens are endocytosed and degraded in lysosomes to bind class II MHC.
3. The peptide-MHC complexes are then transported to the cell surface for recognition by T cell receptors.
Antigens are substances that stimulate the immune system to produce antibodies against them. They enter the body through various sites and are then captured and presented by antigen presenting cells. There are several types of antigens including immunogens, which induce immune responses; tolerogens, which induce tolerance; allergens; and vaccines. An antigen's ability to induce an immune response is called its immunogenicity, while its ability to bind antibodies is its antigenicity. Properties that influence immunogenicity include the antigen's foreignness, size, complexity, degradability, and the recipient's genotype and age. Administration methods like dosage, route, and use of adjuvants can also impact immunogenicity. Antigens are classified as complete if they have
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.
The document summarizes the key mechanisms by which the human immune system generates a diverse repertoire of antibodies from a relatively small number of genes. It describes the somatic variation theory where mutation and recombination of immunoglobulin genes in somatic cells results in high antibody diversity. It explains processes like V(D)J recombination of light and heavy chain genes, junctional diversity, allelic exclusion, somatic hypermutation, and class switching which all contribute to antibody diversity.
1. An immunogen is an agent capable of inducing an immune response, while an antigen is any agent capable of binding to components of the immune system. All immunogens are antigens, but not all antigens are immunogens.
2. Haptens are low molecular weight compounds that are incapable of inducing an immune response alone but can do so when conjugated to a carrier molecule like a protein.
3. For a substance to be immunogenic, it must be foreign, have a high molecular weight and chemical complexity, be degradable, and interact with MHC molecules.
Transplantation involves transferring organs, tissues or cells from one part of the body to another or between individuals. Compatibility of immune molecules like HLA antigens, ABO blood groups, MIC antigens and KIR determines transplant success. Major histocompatibility complex (MHC) molecules control immune response and are targets in transplant rejection. Incompatibility can lead to hyperacute, acute cellular or chronic rejection as well as graft-versus-host disease. Immunosuppressive agents like corticosteroids, calcineurin inhibitors and monoclonal antibodies are used to suppress anti-graft immune responses.
An antigen is any substance that reacts with lymphocytes, while immunogens generate immune responses. Haptens are small molecules that require coupling to carriers to induce responses. Antibody-antigen binding depends on weak interactions between sites on antibodies and epitopes on antigens. Antibodies are produced with a wide variety of binding sites to recognize different antigenic determinants. Factors like foreignness, size, structure, and route of administration influence a substance's immunogenicity.
Preventive Health(Immunization, Vaccination, Prevention of diseaseMuavia Sarwar
This document discusses preventive health care and community pharmacy. It is submitted by 9 individuals and dedicated to community pharmacy. It contains information on primary, secondary and tertiary levels of preventive health care. It also discusses the Expanded Program on Immunization (EPI), the Center for Disease Control (CDC), and Pakistan's National Health Policy. The goals of these programs and policies are to improve population health through disease prevention and health promotion.
SIMILARITIES BETWEEN CLASS I AND CLASS IIPeter Massawe
Both MHC class I and class II are synthesized in the rough endoplasmic reticulum, found on the surface of antigen presenting cells, and their expression is co-dominant. MHC class I presents endogenous antigens to CD8 T cells and binds peptides of 8-10 amino acids, while MHC class II presents exogenous antigens to CD4 T cells and binds peptides of 13-18 amino acids. After binding, MHC class I triggers lysis of infected cells by cytokines, while MHC class II triggers antibody formation by B cells.
Immuniy, Antigen and Antibody, Hypersensitivity reactions and ocular corelati...Raju Kaiti
This document discusses antigen, antibody, and complement systems and types of immune responses and hypersensitivity reactions. It provides an overview of innate and adaptive immunity, cells involved in the immune system including B cells, T cells, and macrophages. It describes the properties of antigens and antibodies as well as the components, functions, and activation pathways of the complement system. The document also discusses the four types of hypersensitivity reactions (type I-IV) and provides examples of conditions that fall under each type of hypersensitivity.
The lymphoid system consists of cells, tissues, and organs that protect the body from foreign invaders. The main cells are lymphocytes like T cells, B cells, and NK cells. Lymphoid tissues include lymph nodes, spleen, tonsils, and Peyer's patches. The thymus and bone marrow are primary lymphoid organs where lymphocytes develop. Secondary lymphoid organs activate lymphocytes and produce an immune response against antigens. Lymph nodes filter lymph and mount immune responses. The spleen filters blood and mounts responses in its white pulp.
The document summarizes epitope prediction and its algorithms. It discusses that epitopes are the portions of antigens responsible for antigen-antibody specificity. There are two main types of epitopes: sequential/continuous epitopes recognized by T helper cells and conformational/discontinuous epitopes recognized by both T and B cells. It then describes several computational algorithms used for predicting B-cell and T-cell epitopes, including Hopp & Woods, Welling's method, Karplus & Schultz parameters, and Kolaskar & Tongaonkar's method. Finally, it lists several databases and servers that can be used for epitope prediction, such as SYFPEITHI, MHCPEP, and EPIM
The lymphatic system collects excess tissue fluid and returns it to the bloodstream. Its components include lymphatic vessels, lymph nodes, and lymph ducts. The immune system protects the body from foreign organisms using lymphocytes, lymphoid tissue, and lymphoid organs like the spleen, thymus, and lymph nodes. Lymphocytes recognize and destroy pathogens. When activated by antigens, they proliferate into memory and effector cells. Disorders can affect the lymphatic vessels or immune function.
The Lymphatic System & Lymphoid Organs And Tissuesmsu
The lymphatic system consists of lymphatic vessels, lymph nodes, and lymphoid tissues that work together to return interstitial fluid to the bloodstream, transport fat from the digestive tract, and help the body fight infection. Lymphatic vessels originate as microscopic capillaries that drain into larger collecting vessels, trunks, and ducts. The right lymphatic duct and thoracic duct are the two main lymphatic trunks that return lymph to the blood circulation. Lymphoid tissues include the lymph nodes, spleen, thymus, and bone marrow that contain lymphocytes like T cells and B cells which help the immune system fight pathogens and cancer cells.
This document discusses antigens and antibodies. It defines antigens as any molecule that can bind specifically to an antibody. Antigens include sugars, lipids, proteins and more. They can be found on microbes or in the environment. The document discusses the properties of antigens including their ability to induce immune responses or tolerance. It also discusses immunogens versus haptens. Factors that influence antigen immunogenicity are also covered such as molecular size, composition, and an antigen's susceptibility to processing and presentation. The role of adjuvants in enhancing immune responses is also summarized.
This document discusses humoral immunity and antibodies. It describes how antibodies are produced by B cells and plasma cells in response to antigens. The primary role of antibodies is protection against reinfection by binding to pathogens and marking them for destruction or neutralization. The document provides details on antibody structure, classes, properties, functions, and role in immune responses.
Antibodies are Y-shaped proteins made up of light and heavy chains that bind to antigens. There are five major classes of antibodies (IgG, IgM, IgA, IgE, IgD) that have different structures and functions. Monoclonal antibodies derived from a single clone are specific for a single epitope, making them useful for research, diagnostics and therapeutics. Monoclonal antibodies find applications in diagnostic tests, diagnostic imaging, immunotoxins to treat cancer, and clearing pathogens from the body. Antibody engineering techniques allow humanization of mouse antibodies for improved safety.
The document summarizes India's immunization programme and history. It discusses how Edward Jenner developed the smallpox vaccine in 1796, leading to smallpox eradication globally by 1977. India launched its Expanded Programme on Immunization in 1978 to provide vaccines for 6 diseases to children under 5 and pregnant women. This programme evolved into the Universal Immunization Programme in 1985 to achieve universal immunization coverage across the country. Significant milestones and achievements of India's immunization efforts are highlighted.
The document discusses antigens, immunogens, epitopes, and major histocompatibility complex (MHC). It defines antigens and immunogens as molecules that can induce an immune response. Epitopes are the specific sites on antigens that antibodies and T cell receptors bind to. MHC proteins present antigen fragments to T cells and are encoded by polymorphic genes that play a role in transplant compatibility.
This document discusses transplant immunology and the major histocompatibility complex (MHC). It covers MHC structure and function, inheritance of MHC antigens, humoral and cellular immunity, antigen presentation, HLA associations with disease, types of transplants, mechanisms of graft rejection, pre-transplant immunological evaluations, and immunosuppressive strategies.
The lymphatic system includes lymph vessels, lymph nodes, and lymphoid organs that work to maintain fluid balance, absorb lipids, filter the blood, and participate in immunity. The lymph vessels carry lymph fluid away from tissues and into the venous circulation. Lymph nodes filter lymph and activate the immune system. Major lymphoid organs are the spleen, thymus, and tonsils, which help fight infection and store blood.
The thymus is an organ located in the upper chest that plays a key role in immune system development. It contains two main areas - the cortex and medulla - which help lymphocytes mature. The thymus contains various cell types that interact to promote T cell differentiation and selection. Epithelial reticular cells form a framework and secrete hormones to guide lymphocyte development. By adolescence, the thymus begins to involute and lose much of its immune function.
The document summarizes adaptive immunity and the immune system. It describes the two types of adaptive immunity - active and passive, which can be acquired naturally or artificially. It also details the roles of B cells and T cells in humoral and cell-mediated immunity, including antibody production, antigen recognition, and immune memory. Hypersensitivities are immune reactions beyond normal responses, classified into four types based on mechanisms.
The document provides an overview of immunohistochemical (IHC) techniques. It discusses the basic principles of IHC, including antigen-antibody reactions and the use of primary and secondary antibodies. It also describes different IHC staining methods such as direct, indirect, and peroxidase-antiperoxidase methods. Key enzymes and chromogens used in IHC are discussed, as well as factors that influence antibody binding such as dilution, incubation time and temperature.
General principles of immunology and MHC - converted.pdfsubhankar9366
1. The document discusses principles of immunology including recognition, effector response, memory response, antigens, immunogens, epitopes, and types of immunity.
2. It describes the major classes of antigens that can induce an immune response and examples of cross-reactivity between antigens.
3. The roles and expression of MHC class I and II molecules are summarized, including their involvement in antigen processing and presentation to T cells.
Antigen and antibody are essential components of the immune system. Antigens are substances that induce an immune response through the production of antibodies. The key properties of antigens are that they are foreign, have specific epitopes that antibodies bind to, and can range in size. Antibodies are Y-shaped proteins produced by B cells in response to antigens. The five major classes of antibodies are IgG, IgM, IgA, IgD, and IgE, which have different structures and functions such as pathogen neutralization, opsonization, and activation of immune cells.
Here are five things to know about coronavirus tests: PCR and antigen tests are the most common but they work differently. While antigen tests look for proteins ...
An antigen is any substance that causes your immune system to produce antibodies against it. This means your immune system does not recognize the substance, and is trying to fight it off. An antigen may be a substance from th
This document discusses antigens and concepts in vaccine development. It begins by defining antigens and classifying them as exogenous or endogenous. It then discusses the differences between immunogenicity and antigenicity, and lists factors that influence immunogenicity such as molecular size, chemical composition, and adjuvants. The document also covers epitopes, mitogens, and superantigens. Finally, it discusses the different stages of vaccine development from pre-clinical to clinical trials and licensing, and methods used in vaccine manufacturing.
The document discusses the nature of antigens and the major histocompatibility complex (MHC). It defines immunogens and antigens, noting that immunogens can trigger an immune response while not all antigens are immunogens. Antigens are usually large proteins or polysaccharides from foreign organisms. Factors like age, health, dose, and route of exposure can influence the immune response. The document also discusses epitopes, haptens, adjuvants, and the relationship of antigens to the host (autoantigens, alloantigens, heteroantigens). It provides details on MHC genes, class I and class II MHC structure and function in antigen processing and presentation to T cells.
ANTIGEN & ANTIBODY AND THEIR REACTIONS Gayathri Nair
This document discusses antigens, antibodies, and antigen-antibody reactions. It defines antigens as molecules that can be recognized by B cells or T cells. Antibodies are globulin proteins that react specifically with antigens. The document outlines antibody structure, including heavy and light chains, variable and constant regions, and classes of immunoglobulins. It also describes antigen specificity, determinants, haptens, and superantigens.
This document discusses antigens and their classification. It defines antigens as substances that can induce an immune response. Antigens are classified as either exogenous (external) or endogenous (internal) antigens. Exogenous antigens enter the body from the external environment, while endogenous antigens are further divided into xeno-genic, allogenic, and autologous antigens based on their origin. The document also discusses the properties of immunogens and antigens, as well as factors that contribute to immunogenicity.
Adaptive immunity and B cell development involve multiple steps:
1. B cells develop in the bone marrow from hematopoietic stem cells over 1-2 weeks to become mature B cells expressing surface immunoglobulin.
2. Mature B cells leave the bone marrow and migrate to secondary lymphoid tissues where they encounter antigens.
3. Upon antigen recognition, B cells activate, proliferate, and differentiate into either plasma cells that secrete antibodies or memory B cells. Plasma cells localize mainly to the bone marrow.
This document provides an overview of immunogenetics. It begins with an agenda that defines immunogenetics and discusses immune responses, diversity mechanisms, and immunodeficiency diseases. The document then defines immunogenetics as the study of genetic control of immune cells and molecules. It focuses on structure and organization of immune response genes, HLA antigens and disease association, generation of antibody and T cell diversity. Mechanisms creating diversity for B cell receptors, T cell receptors and HLA are described. Finally, immunodeficiency diseases associated with impaired immune function are briefly discussed.
1) An antigen is any substance that can induce an immune response by being immunogenic or antigenic. Immunogenicity is the ability to induce an immune response through B and T cells. Antigenicity is the ability to bind to antibodies or T cell receptors.
2) An epitope is the smallest part of an antigen that can induce an immune response. It consists of 4-5 amino acids or sugars that bind to T or B cell receptors.
3) A hapten is a small molecule that is not immunogenic on its own but can bind antibodies when attached to a larger carrier molecule, making it immunogenic.
This document provides an overview of immunochemistry and the immune system. It discusses the innate and acquired immune responses, cells of the immune system including lymphocytes, antigens, immunogens, and the mechanisms of humoral and cell-mediated immunity. The key cells discussed are B lymphocytes and T lymphocytes, and their roles in the adaptive immune response through antibody production and activation of other immune cells.
This document discusses antigens, vaccines, and recent advances. It covers topics such as:
- Types of antigens including exogenous and endogenous antigens.
- Factors that influence immunogenicity including foreignness, molecular size, and adjuvants.
- The concept of vaccine development including pre-clinical trials in animals and clinical trials in humans.
- Methods of vaccine manufacturing to ensure safety, including propagation, purification, and formulation according to good manufacturing practices.
- Major types of vaccines including live attenuated, inactivated, subunit, toxoid, recombinant, mRNA, DNA, and recombinant vector vaccines.
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.
The document discusses antigens and the major histocompatibility complex (MHC). It describes how immunogens trigger adaptive immune responses through antibodies or T cells. The ability of an immunogen to stimulate a response depends on factors like its size, complexity, and ability to be processed and presented by MHC molecules on antigen-presenting cells. MHC molecules play a key role in antigen presentation to T cells in order to activate both humoral and cellular immunity. The MHC genes encode for class I and class II molecules that bind peptides and transport them to the cell surface for recognition by CD8+ or CD4+ T cells, respectively.
This document discusses antigens and haptens. It defines antigens as macromolecules that elicit an immune response through antibody formation. It classifies antigens as exogenous or endogenous, and further divides endogenous antigens. It distinguishes immunogenicity from antigenicity and defines haptens as low molecular weight compounds that are antigenic but not immunogenic unless coupled to a carrier protein. It provides examples of haptens and describes tests used to detect antigens and haptens.
The major histocompatibility complex (MHC) is a cluster of genes found in mammals that plays a key role in the immune system by helping the body distinguish self from non-self. The MHC was discovered through studies of inbred mouse strains and includes polymorphic glycoproteins divided into three main classes. MHC Class I and II are best known for presenting antigen peptides and interacting with T-cell receptors. Genes in the MHC are highly polymorphic, linked, and inherited as haplotypes from each parent. This polymorphism allows recognition of a diverse range of antigens and is advantageous for the immune system.
Immunogens or antigens are foreign substances that elicit an immune response when introduced to the body. They are recognized by antibodies or T-lymphocytes. Immunogens can induce antibody formation themselves, while haptens require a carrier molecule to produce an immune response. Antigens are presented on antigen-presenting cells and recognized by B and T cells, initiating humoral or cell-mediated immunity. Exogenous antigens from bacteria, viruses, and other external sources are phagocytosed and processed, while endogenous antigens from infection or autoimmunity are presented via MHC I molecules.
The major histocompatibility complex (MHC) molecules are membrane-bound glycoproteins that function as specialized antigen-presenting molecules. There are two main classes of MHC molecules - class I and class II. Class I molecules present intracellularly derived antigens to CD8+ T cells, while class II molecules present extracellular antigens engulfed by antigen-presenting cells to CD4+ T cells. Both classes of MHC molecules form stable complexes with peptide ligands within a binding groove and display them on the cell surface for recognition by T-cell receptors.
1. • NATURE OF ANTIGEN AND THE MAJOR
HISTOCOMPATIBILITY COMPLEX
2. INTRODUCTION
Antigen refers to macromolecules that are
capable of eliciting formation of antibodies or
sensitized T cells in an immunocompetent host.
Means any agent which can generate antibody.
Immunogens refer to macromolecule capable
of triggering an adaptive immune response.
3. • All immunogens are antigens but not all antigens are
immunogens.
• All antigen are recognized by specific antibodies or T
cell receptor not all antigen can evoke immune
response.
• Those antigen that are capable of inducing immune
response are called immunogens.
4. This response is actually caused by combination of factors:
Nature of immunogens itself.
Genetic coding of major histocompatibility complex (MHC)
that combine with an immunogen before T cells are able to
respond.
Immunogen processing and presentation
6. b) Health of an individual
Healthy individuals normally respond fully to
the immunogens while malnourished,
fatigued or stressed ones are less likely to
have a successful immune response
7. ) Dose of immunogens
Generally, the larger the dose one is exposed
to, the greater the immune response.
However, very large doses may result in T- and
B-cell tolerance.
8. Route of inoculation
Immunogen entrance routes to the body
determine the cell populations which will be
involved in the response and how much will
be needed to trigger a response.
Such routes are intravenous, intradermal,
subcutaneous and oral.
9. ) Genetic capacity
The stronger the genes involved in allowing
the individuals to respond to the
immunogens, the greater the ability to
influence the immune response.
10. TRAITS OF IMMUNOGENS
• Immunogens: are molecules that elicits
immune
response, It triggers an immune response.
e.g. incase of the humoral response or the B-
cells.
The ability of immunogen to stimulate a host
response depends on the following
characteristics.
11. • A: Properties of immunogecity
• 1)Molecular size
• 2) Chemical composition and molecular
complexity.
• 3) Foreignness
• 4) The ability to be processed and presented
with MHC molecules.
12. • B: Contribution of biological system.
• 1) Genotype of the recipient animal.
• 2) Immunogen dosage and route of
administration.
• Usually immunogen has the molecular weight
between 10000- 100000 Daltons to recognized by
immune system
13. • Immunogenicity is also determined by a
substance chemical composition and
molecular complexity.
• Protein and polysaccharides are the best
immunogens .
• Protein are powerful immunogens because
they are made up of a variety of units known
as amino acid .
14. NATURE OF EPITOPES
Epitopes are smaller molecular shaped parts
of the immunogen that is recognized by the
immune system.
For proteins there is evidence that,amino
acids epitopes recognized by B- cells may
consist of 6-15 amino acids.
15. In other hand the large molecules may have
numerous epitopes, where by each one tends
to be capable of triggering specific antibody
production or a T-cell response.
Epitopes may be repeating copies or may tend
to have have different specificities.They can be
sequential/linear or conformational.
16. CLASSIFICATION OF EPITOPES
Epitopes are classified into two categories:-
Linear/sequential epitopes- are formed by a
specific sequence as amino acids are following
one another in a single chain.
Confirmational epitope- are formed due to the
folding of one or multiple chain bringing certain
amino acids from different segment of linear
sequence/sequences into proximity with each
other to be recognized.
17. Epitopes recognized by the B-cells differ from
those recognized with T-cells.
Fore instance surface antibodies of B-cells may
react with both linear and the conformational
epitope.
But for T-cells recognizes only as a part of a
complex formed with MHC proteins on the
surface of an antigen presenting cells.
18. HAPTENS
• Are non immunogenic material that when
combine with a carrier creat a new antigenic
determinant.
• Once antibody production is initiated, the
hapten is capable of reacting with antibody
even when the haptens is not complexed to a
carrier molecule
19. • However precipitation or agglutination
reaction will not occur because the haptens
has a single determinant site and can not form
a cross link with more than one antibody
molecule that are necessary for agglutination
or precipitation
20. • A good example of haptens is an allergic
reaction to poison called “ivy” containing a
chemical substance called catechols which are
haptens.
• Once in contact with the skin this can couple
with tissue protein to form immunogens that
give rise to contact dermatitis.
22. RELATIONSHIP OF ANTIGENS TO THE
HOST
Antigens can be placed in broad categories
according to their relationship to the host.
Autoantigens are those antigens that belongs
to the host.
-These do not evoke an immune response under
normal circumstances.
23. Alloantigens are those from other member s
of the host’s species , and these are capable
of eliciting an immune responses.
-They are importance in tissue transplantations
and blood transfusions.
24. Heteroantigens are those antigens from other
species such are other animals, plants or
microorganisms.
Heterophile antigens are heteroantigens that
exists in unrelated plants or animals but are
either identical or closely related in structure
so that antibody to one will cross reacted with
antigen of the other
25. • Example of heterophile antigen is blood group
A and B antigens of human related to bacterial
polysaccharides.
26. ADJUVANTS
• An adjuvant is a substance administered with an
immunogen that increases the immune response.
• It acts by producing local inflammatory response
that attracts a large number immune system cells
to the injection site.
• Example aluminum salts and Freund’s complete
adjuvants.
27. Adjuvant are thought to enhance the immune
response by:
Prolonging the existence of immunogen in the
area
Increasing the effective size of the immunogen
Increasing the number of macrophages involved
in antigen processing.
28. MAJOR HISTOCOMPATIBILITY
COMPLEX (MHC
• Genetic capability to mount an immune response
is linked to a group of molecule originally reffered
to as human leukocyte antigen (HLA)
• These antigen are also known as MHC molecule
because they determine whether transplanted
tissue is histocompatible and thus accepted or
recognized as foreign and rejected.
29. • MHC molecules are actually found on all
nucleated cells in the body, and they play a
role in the development of both humoral and
cellular immunity
• They are relevant clinically because they
may be involved in transfusion reaction, graft
rejection, and autoimmune disease
30. GENES CODING FOR MHC MOLECULES
(HLA ANTIGEN)
• MHC is a polymophic system in human, this
is because it comprises so many possible
alleles at each location
• Polymorphism is essential to our survival
because MHC molecule play a vital role in
triggering immune response to diverse
immugen
31. • Gene coding for the MHC found in
chromosome 6 and are divided into three
categories or classes
• Class I molecules are coded for a three
different location or loci, termed A, B and C
32. • Class II gene are situated in the D region and
there are several different loci known as DR, DQ
and DP
• In class II there is a gene that codes for alpha
chain and one or more gene for the beta chain
• Between class I and class II region on
chromosome 6 is the area for class III gene
which code for complement protein and
cytokines
33. • Class III are not expressed on cell surface, but
have immune response, class I and class II are
responsible in antigen recognition
• Haplotype is the package of inherited MHC
gene
or is the group of gene within an organism
that was inherited together from a single parent
34. • Thus each inherited chromosomal region
consists of a package of gene for A, B, C, DR,
DP, and DQ
• Full genotype would consist of two of each
gene at a particular locus because there are
numerous allele or variant forms at each locus
35. • An individual MHC type is about as unique as
a fingerprint
figure; MHC location for the class I, II and III gene on
chromosomes 6
36. STRUCTURE OF CLASS I MOLECULES
Class I molecules are expressed in all
nucleated cells.
Expressed more in lymphocytes and weakly
expressed in liver hepatocytes, neuronal cells,
muscle cells and sperm.
37. Each class I is a glycoprotein dimer made up of
two noncovalently linked polypeptide chains, a
and β2-microglobulin
α- chain is folded into three domains α1, α2and
α3 and it has molecular weight of 45,000daltons
β2-microglobulin is the lighter chain has
molecular weight of 12000daltons
38. β2-microglobulin chain does not penetrate
the cell membrane while α-chain penetrates
via transmembrane segment
α1 and α2 forms the deep groove at the top
of the molecule that acts as the peptide-
binding site in antigen recogniction
39. α3 region of a-chain reacts with CD8 on
cytotoxic cells
Another group of called non-classical class I
molecules are not expressed on the surface of
cells and are not used in antigen recognition.
40. STRUCTURE OF CLASS II MHC
MOLECULES
The occurrence of class II MHC molecules is
much more restricted than class I.
Class II MHC molecules are primarly found in
antigen presenting cells which include B-
lymphocytes, monocytes, macrophages and
dentritic cells.
41. The MHC class II molecules consist of two
non-covalently bound polypeptide chains that
are both encoded by genes in the MHC
complex
α-chain has molecular weight of
33,000daltons and b-chain has molecular
weight of 27,000daltons
42.
43. Each chain has two domains in which α1 and
β1 domains come together to form peptide-
binding site.
The main role of class I and class II MHC
molecules is to bind peptide inside the cells
and transport them to the plasma membrane
where T cells can recognize them in process
known as antigen presentation
44. Class I molecules mainly present peptides that have
been synthesized inside the cell to CD8(cytotoxic) cells.
Class II molecules present exogenous antigen to CD4
(helper) cells
Class I are thus watchdogs of viral, tumor and certain
parasitic antigens synthesized inside the cell, while
class II stimulate CD4 in case of bacterial nfections or
presence of other material that is endocytosed by the
cell.
45. Roles of class I molecule.
MHC class 1 synthesized in the rough
endoplasmic reticulum.
It bind peptide within the cell (endogenous
peptide) and transport them to the plasma
membrane where it recognized by CD8+ T
cell.
CD8+ T cell produce cytokines that cause lysis
of the target cell .
47. Roles of class II molecule
It transported from endoplasmic reticulum to
an endosomal compartment before they can
bind peptide.
Due to invariant chain class II molecule bind
with exogenous peptide that favored by low
PH of endosomal compartment
48. Cont…
On the cell surface class II molecule
recognized by CD4 (T helper) cell
CD4+ T cell trigger the B cell for the formation
of antibody.