10. Antigens - Notes taken from the lecture of Sir Joseph Joy Banzon, RMT PDF

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Summary

IMMUNOLOGY SEROLOGY ANTIGENS ANTIGENS a substance that reacts with antibody or sensitized cells but may or may not provoke an immune reponse IMMUNOGEN a substance capable of eliciting the formation of immunoglobulins or sensitized cells in an immunocompetent host immunogens are antigens. But not all...

Description

IMMUNOLOGY & SEROLOGY

ANTIGENS ANTIGENS - a substance that reacts with antibody or sensitized cells but may or may not provoke an immune reponse IMMUNOGEN - a substance capable of eliciting the formation of immunoglobulins or sensitized cells in an immunocompetent host “All immunogens are antigens. But not all antigens are immunogens.” PARTS OF AN ANTIGEN: 1. EPITOPE - the antibody determinant/site - molecular shape of configurations that are recognized by antibody or T-cells - may be either linear or conformational, or may have repeating units / different specificities 2. HAPTEN - responsible for the specificity of an antigen - it is where epitopes are placed - nonimmunogenic materials that when combines with a carrier, it creates new antigenic determinants - smaller part of an antigen 3. CARRIER - protein molecules responsible to give the antigen its required size/weight - bigger part of an antigen HAPTEN

CARRIER

COMPLETE Ag

Capacity to bind with Ab Capacity to stimulate Ab production VALENCE: number of combining sites CHARACTERISTICS OF AN ANTIGEN:  FOREIGNESS: “The more foreign the substance is, the more immunogenic.”  HIGH MOLECULAR WEIGHT  10,000 D = minimum size to be classified as an immunogen  40,000-50,000 D = good immunogen  1 million D = potent immunogen  MOLECULAR / CHEMICAL COMPLEXITY: “The more complex, the more immunogenic.”  DIGESTABILITY  Proteins Best immunogen  Carbohydrates  Glycoprotein  Glycolipid Poor immunogen  Nucleic Acid  AVAILABILITY & ACCESIBILITY OF REACTIVE SITES

JOYCE ANN S. MAGSAKAY

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BS MEDICAL LABORATORY SCIENCE

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OLFU VALENZUELA

IMMUNOLOGY & SEROLOGY

ANTIGENS TYPES OF ANTIGEN: 1. AUTOANTIGENS: antigens that belongs to the host 2. ISO/ALLOANTIGENS: derived from the body of other individuals of the same species 3. HETEROANTIGENS: derived from another species 4. HETEROPHILE ANTIGENS: those that exist in unrelated plants or animals but which are either identical or closely related in structure so that antibody to one will cross-react with antigen of the other OTHER TYPES OF ANTIGEN THYMUS DEPENDENT ANTIGEN THYMUS INDEPENDENT ANTIGEN - capable of mounting immune response - capable of mounting immune response without the help from Tprovided there’s assistance from T-helper cells helper cells - can stimulate B-cells - capable of stimulating B-cells - capable of inducing producting of memory - not capable of inducing proliferation of memory cells cells - can induce B-cell to form different - only IgM can be produced immunoglobulins such as IgG, IgA, IgM, IgD, IgE * TYPE 1: has inherent mitogenic property Examples: Bacterial polysaccharide, Brucella abortus * TYPE 2: - lineary arranged mnotously repeating epitope - Lymphocyte capping: IgG migrates towards one side of the B-cell (Capped B-cell) Examples: Pneumococcal polysaccharide, Salmonella-Polymerized flagellin, Hapten conjugated ficoll, (Polysucrose), Dextran

- Examples: Viral hemagglutinin, Diphtheria toxin, Purified Protein Derivative (PPD)

FACTORS INFLUENCING THE IMMUNE RESPONSE:  Age  Dose  Route of Inoculation  Health status of the host  Genetics ADJUVANTS - a substance administered with an immunogen that increases immune response - Examples: Aluminum salts, complete Freund’s adjuvant WAYS OF ENHANCING THE IMMUNE RESPONSE BY ADJUVANTS:  It prolongs the existence of immunogen in the area  It increases the effective size of an immunogen  It increases the number of macrophages involved in antigen processing

JOYCE ANN S. MAGSAKAY

|

BS MEDICAL LABORATORY SCIENCE

|

OLFU VALENZUELA...