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Antigen overview

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KUVEMPU UNIVERSITY PG DEPARTMENT OF BIOTECHNOLOGY SAHYADRI SCIENCE COLLEGE SHIVAMOGA. SEMINAR TOPIC ANTIGENS SUBMITTED BY UNDER THE GUIDENCE OF RANJITHA SL Dr. BANUMATHI I MSc BIOTECHNOLOGY LECTURER Email Id: ranjithasl810@gmail.com PG DEPARTMENT OF BIOTECHNOLGY SAHYADRI SCIENCE COLLEGE SAHYADRI SCIENCE COLLEGE SHIVAMOGGA .
CONTENT  INTRODUCTION  ANTIGENS  IMPORTANCE  TYPES  HAPTENS  EPITOPES AND PARATOPES  PROPERTIES/FACTORS  ADJUVENTS  TESTS  CONCULSION  REFERENCES
ANTIGENS
INTRODUCTION • Antigens are molecules that tigger an immune response in the body they are recognised by the immune system as foreign or non self .the immune system them mounts a defense against these antigens. Often by producing antibodies. • Antigens can be found on the surface of bacteria, viruses, parasites, and other foreign invaders. They can be also be present in substances like pollen, dust mites, and non – self antigens, allowing it to target foreign substances without attacking the body’s own tissues.
ANTIGENS • Antigens are foreign substances that can be recognized by the immunoglobulin receptor of B cell or by the T cell receptors when complexed with MHC • IMMUNOGENICITY : The ability to induce a humor/cell mediated response is a property of a substance known as antigen called immunogen • ANTIGENICITY : The ability to combine specifically with antibodies or cell surface receptors. all molecules that have the property of immunogenicity also have the property of antigenicity
IMPORTANCE OF ANTIGENS Triggering immune response Specificity Activation of immune cells Antibody production Immunological memory Vaccine development Cancer Research and study Diagnostic Tools Immunotherapy development
TYPES OF ANTIGEN CLASSIFICATION BASED ON ORIGIN Exogenous Antigens Endogenous antigens Auto antigens Tumors antigens
EXOGENOUS ANTIGENS ❶ ORIGIN ❷ PROCESSING ❸ IMMUNE RESPONSE • Exogenous antigens are foreign substances that originate outside the body. • Once exogenous antigens enter the body ,they are taken up by immune cells, primarily antigen- presenting cells(APCs). • The presentation of exogenous antigen on APCs triggers an immune response. • They enter the body through various routes such as inhalation ,ingestion or injection. • APCs process their antigen and present them on their surface in a way that is recognizable by the other immune cells • This involves the activation of T Cells and B Cells • They come from sources like bacteria , viruses, fungi, parasites and allergens • The leading to the production of the antibodies and cytotoxic then T-Lympocytes that can target and eliminate the
ENDOGENOUS ANTIGENS ❶ ORIGIN ❷ EXAMPLES • These antigens are produced within the cells of the body • Endogenous antigens includes viral proteins, when viruses infect a cells they take over the cells machinery and produces viral proteins • They aren't foreign invaders like exogenous(bacteria/viruses) instead, they are generated by normal cellular processes, such as protein synthesis and degradation. • These processes can sometimes leads to the production of abnormal or altered protein that the immune system recognize as
AUTO ANTIGENS ❶ SELF RECOGNISATION ❷ IMMUNE DYSREGULATION ❸ TISSUE DAMAGE • The immune system normally distinguishes between self and non self. • Autoimmune disorder occur when the immune system loses tolerance for self antigen • Autoantigens can trigger the production of antibodies and T cells that attack the body's own tissues. • Autoantigens are molecules that are normally found within the body ,but are mistakenly recognized as foreign by the immune system. • This can happen due to a variety of factor , including genetic predisposition, environment triggers , and infections. • This can lead to a wide range of symptoms depending on the specific tissues and organs involved • When the immune system attacks self antigens,
TUMOR ANTIGENS Tumor antigen are those antigens that are presented by the MHC – I (Major Histocompatibility Complex) molecules on the surface of tumor cells. These antigens can sometimes be presented only by tumor cells and never by the normal ones . In this case they are called tumor specific antigens ( TASAs)and typically result from a tumor specific mutation .
ON THE BASIS OF THE IMMUNE RESPONES IMMUNOGENS :These may be protein /polysaccharide s and can generate an immune response on their own 1 TOLEROGENS : It induces immune tolerance ,meaning it does not trigger an immune response 2 HAPTENS : These are non – protein ,small molecules that requires a carrier molecules to induces an immune response 3 SUPERANTIGEN :Stimulate a very strong immune response and it activating a large number of immune cells 4
BASED ON FUNCTION Classified into types: COMPLETE ANTIGEN : Substances which can induced antibody formation by themselves and can react specifically with these antibodies INCOMPLETE ANTIGEN/HAPTENS :Substances unable to induce antibody formation on its own but can become immunogenic when covalently linked to protein ,called carrier protein .
HAPTENS • Haptens is derived from the Greek word haptein mean “to fasten”. • The term Hapten was first coined by karl Landsteiner. • These are low molecular weight substance that are antigenic but not immunogenic • Its biological importances substances-drugs ,peptide hormones , steroid hormones , can function as hapten. • Eg :Penicillin
DIFFERENCE B/w ANTIGEN AND HAPTENS
EPITOPES AND PARATOPES EPITOPE(ANTIGENIC DETERMINANT) It includes sugars, organic acids and bases, amino acid chains, hydrocarbons and aromatic groups. PARATOPES The Antibodies contains antigen binding site
BASED ON BIOLOGICAL CLASSES OF ANTIGEN • T DEPENDENT ANTIGEN :Antigen that requires help of T cells to activate B cells for antibody production • T INDEPENDENT ANTIGEN : Antigen directly stimulate antibody production without the help of T cells
PROPERTIES /FACTORS INFLUENCING OF ANTIGENS 1. FOREIGNNESS • Antigen must be foreignness to immune system • According to Burnnet ’s clone selection theory , “forginness (non – self) means substances that never contact with lymphocytes embryo period. 2.CHEMICAL NATURE AND COMPOSITION • Antigen are mainly proteins and polysaccharides • Chemical nature of antigen protein ,polysaccharides ,nucleoproteins ,glycoprotein ,steroid hormones ,bacterial cells ,viruses 3.MOLECULAR SIZE • The antigens have a molecular mass of 14000 to 600000 Da • Highly antigenic are tetanus toxoid (50000),Egg albumin(42700 Da),Thyroglobulin (662000 Da)
CONTINUE….. 4.DEGRADABILITY • Antigens that are easily phagocytosed are generally more immunogenic. • This is because for most antigen (T-dependent antigens) the development of an immune response that the antigen be phagocytosed , processed to helper T –cells by an antigen presenting cell (APC). 5.DOSE AND CONCENTRATION: Higher doses and concentration can trigger stronger immune responses. 6.GENETIC FACTORS: Genetic polymorphism and epigenetic modification can affect immune responses to specific antigens.
ADJUVENTS • Substances that when mixed with an antigen and injected with it ,enhance the immunogenicity of that antigen. • Used to boost the immune response when an antigen has low immunogenicity or when small amount of antigen are available • Eg: The antibody response of mice to immunization with BSA can be increased 5 fold or more ,if the BSA is administered with an adjuvant . • Freund’s incomplete adjuvant : contains aqueous solution , mineral oil , mannide monooleate. • Freund’s complete adjuvant :Heat killed
TESTS FOR ANTIGENS ELISA RIA CFT IMMUNOFLUORESENCE NEUTRALIZATION TEST IMMUNOHISTOCHEMISTRY
CONCULSION Antigens are substances that stimulate an immune response , playing a crucial role in the body’s defense against pathogens and diseases .they can originate from inside r outside the body , antigens trigger an immune response.
REFERENCES 1.Kuby, J.(2013),Immunology (7th ed.).W.H.Freeman and company 2.Gangal,Sudha and Shubhangi Sontakke (2020) ,Textbook of Basic and Clinical Immunolo.,gy . (3rd ed )CBS Publisher
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Antigen_ppt(_RANJITHA_SL)_.presentation.

  • 1. KUVEMPU UNIVERSITY PG DEPARTMENT OF BIOTECHNOLOGY SAHYADRI SCIENCE COLLEGE SHIVAMOGA. SEMINAR TOPIC ANTIGENS SUBMITTED BY UNDER THE GUIDENCE OF RANJITHA SL Dr. BANUMATHI I MSc BIOTECHNOLOGY LECTURER Email Id: ranjithasl810@gmail.com PG DEPARTMENT OF BIOTECHNOLGY SAHYADRI SCIENCE COLLEGE SAHYADRI SCIENCE COLLEGE SHIVAMOGGA .
  • 2. CONTENT  INTRODUCTION  ANTIGENS  IMPORTANCE  TYPES  HAPTENS  EPITOPES AND PARATOPES  PROPERTIES/FACTORS  ADJUVENTS  TESTS  CONCULSION  REFERENCES
  • 4. INTRODUCTION • Antigens are molecules that tigger an immune response in the body they are recognised by the immune system as foreign or non self .the immune system them mounts a defense against these antigens. Often by producing antibodies. • Antigens can be found on the surface of bacteria, viruses, parasites, and other foreign invaders. They can be also be present in substances like pollen, dust mites, and non – self antigens, allowing it to target foreign substances without attacking the body’s own tissues.
  • 5. ANTIGENS • Antigens are foreign substances that can be recognized by the immunoglobulin receptor of B cell or by the T cell receptors when complexed with MHC • IMMUNOGENICITY : The ability to induce a humor/cell mediated response is a property of a substance known as antigen called immunogen • ANTIGENICITY : The ability to combine specifically with antibodies or cell surface receptors. all molecules that have the property of immunogenicity also have the property of antigenicity
  • 6. IMPORTANCE OF ANTIGENS Triggering immune response Specificity Activation of immune cells Antibody production Immunological memory Vaccine development Cancer Research and study Diagnostic Tools Immunotherapy development
  • 7. TYPES OF ANTIGEN CLASSIFICATION BASED ON ORIGIN Exogenous Antigens Endogenous antigens Auto antigens Tumors antigens
  • 8. EXOGENOUS ANTIGENS ❶ ORIGIN ❷ PROCESSING ❸ IMMUNE RESPONSE • Exogenous antigens are foreign substances that originate outside the body. • Once exogenous antigens enter the body ,they are taken up by immune cells, primarily antigen- presenting cells(APCs). • The presentation of exogenous antigen on APCs triggers an immune response. • They enter the body through various routes such as inhalation ,ingestion or injection. • APCs process their antigen and present them on their surface in a way that is recognizable by the other immune cells • This involves the activation of T Cells and B Cells • They come from sources like bacteria , viruses, fungi, parasites and allergens • The leading to the production of the antibodies and cytotoxic then T-Lympocytes that can target and eliminate the
  • 9. ENDOGENOUS ANTIGENS ❶ ORIGIN ❷ EXAMPLES • These antigens are produced within the cells of the body • Endogenous antigens includes viral proteins, when viruses infect a cells they take over the cells machinery and produces viral proteins • They aren't foreign invaders like exogenous(bacteria/viruses) instead, they are generated by normal cellular processes, such as protein synthesis and degradation. • These processes can sometimes leads to the production of abnormal or altered protein that the immune system recognize as
  • 10. AUTO ANTIGENS ❶ SELF RECOGNISATION ❷ IMMUNE DYSREGULATION ❸ TISSUE DAMAGE • The immune system normally distinguishes between self and non self. • Autoimmune disorder occur when the immune system loses tolerance for self antigen • Autoantigens can trigger the production of antibodies and T cells that attack the body's own tissues. • Autoantigens are molecules that are normally found within the body ,but are mistakenly recognized as foreign by the immune system. • This can happen due to a variety of factor , including genetic predisposition, environment triggers , and infections. • This can lead to a wide range of symptoms depending on the specific tissues and organs involved • When the immune system attacks self antigens,
  • 11. TUMOR ANTIGENS Tumor antigen are those antigens that are presented by the MHC – I (Major Histocompatibility Complex) molecules on the surface of tumor cells. These antigens can sometimes be presented only by tumor cells and never by the normal ones . In this case they are called tumor specific antigens ( TASAs)and typically result from a tumor specific mutation .
  • 12. ON THE BASIS OF THE IMMUNE RESPONES IMMUNOGENS :These may be protein /polysaccharide s and can generate an immune response on their own 1 TOLEROGENS : It induces immune tolerance ,meaning it does not trigger an immune response 2 HAPTENS : These are non – protein ,small molecules that requires a carrier molecules to induces an immune response 3 SUPERANTIGEN :Stimulate a very strong immune response and it activating a large number of immune cells 4
  • 13. BASED ON FUNCTION Classified into types: COMPLETE ANTIGEN : Substances which can induced antibody formation by themselves and can react specifically with these antibodies INCOMPLETE ANTIGEN/HAPTENS :Substances unable to induce antibody formation on its own but can become immunogenic when covalently linked to protein ,called carrier protein .
  • 14. HAPTENS • Haptens is derived from the Greek word haptein mean “to fasten”. • The term Hapten was first coined by karl Landsteiner. • These are low molecular weight substance that are antigenic but not immunogenic • Its biological importances substances-drugs ,peptide hormones , steroid hormones , can function as hapten. • Eg :Penicillin
  • 16. EPITOPES AND PARATOPES EPITOPE(ANTIGENIC DETERMINANT) It includes sugars, organic acids and bases, amino acid chains, hydrocarbons and aromatic groups. PARATOPES The Antibodies contains antigen binding site
  • 17. BASED ON BIOLOGICAL CLASSES OF ANTIGEN • T DEPENDENT ANTIGEN :Antigen that requires help of T cells to activate B cells for antibody production • T INDEPENDENT ANTIGEN : Antigen directly stimulate antibody production without the help of T cells
  • 18. PROPERTIES /FACTORS INFLUENCING OF ANTIGENS 1. FOREIGNNESS • Antigen must be foreignness to immune system • According to Burnnet ’s clone selection theory , “forginness (non – self) means substances that never contact with lymphocytes embryo period. 2.CHEMICAL NATURE AND COMPOSITION • Antigen are mainly proteins and polysaccharides • Chemical nature of antigen protein ,polysaccharides ,nucleoproteins ,glycoprotein ,steroid hormones ,bacterial cells ,viruses 3.MOLECULAR SIZE • The antigens have a molecular mass of 14000 to 600000 Da • Highly antigenic are tetanus toxoid (50000),Egg albumin(42700 Da),Thyroglobulin (662000 Da)
  • 19. CONTINUE….. 4.DEGRADABILITY • Antigens that are easily phagocytosed are generally more immunogenic. • This is because for most antigen (T-dependent antigens) the development of an immune response that the antigen be phagocytosed , processed to helper T –cells by an antigen presenting cell (APC). 5.DOSE AND CONCENTRATION: Higher doses and concentration can trigger stronger immune responses. 6.GENETIC FACTORS: Genetic polymorphism and epigenetic modification can affect immune responses to specific antigens.
  • 20. ADJUVENTS • Substances that when mixed with an antigen and injected with it ,enhance the immunogenicity of that antigen. • Used to boost the immune response when an antigen has low immunogenicity or when small amount of antigen are available • Eg: The antibody response of mice to immunization with BSA can be increased 5 fold or more ,if the BSA is administered with an adjuvant . • Freund’s incomplete adjuvant : contains aqueous solution , mineral oil , mannide monooleate. • Freund’s complete adjuvant :Heat killed
  • 22. CONCULSION Antigens are substances that stimulate an immune response , playing a crucial role in the body’s defense against pathogens and diseases .they can originate from inside r outside the body , antigens trigger an immune response.
  • 23. REFERENCES 1.Kuby, J.(2013),Immunology (7th ed.).W.H.Freeman and company 2.Gangal,Sudha and Shubhangi Sontakke (2020) ,Textbook of Basic and Clinical Immunolo.,gy . (3rd ed )CBS Publisher