Honours / Core Course (CC)
IMMUNOLOGY
Unit 1: Overview of Immune System
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Introduction – concept of health and disease, Cells and organs of the Immune system
Q.What are the fundamental differences in antigen recognition between T cells and B cells?
Unit 2: Innate and Adaptive Immunity
Anatomical barriers, Inflammation, Cell and molecules involved in innate immunity, Adaptive immunity (Cell mediated and humoral).
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Q.a)What is epitope? b)Give examples of immune components related to recognition of antigen.
a) Epitopes are the immunologically active regions on a complex antigen, the regions that actually bind to B-cell or T-cell receptors. An epitope is the part of an antigen that interacts with the antigen-specific receptor or antibody. Strictly speaking, an epitope is determined by the specificity of the clonally distributed receptor to which an antigen binds. However, the part of an antigen that can reproducibly elicit B cell or T cell responses is often referred to as an epitope without reference to the specificity defined by the particular receptor. Epitopes, which are often used interchangeably with antigenic sites or antigenic determinants, can be classified as B cell epitopes or T cell epitopes on the basis of the types of cellular responses they elicit.
b)Related but distinct cell membrane molecules are responsible for antigen recognition by the immune system. They are—
i)Membrane bound antibodies on B-cells,
ii)T-cell receptors,
iii)Class I MHC molecules present on all nucleated cells,
iv)Class II MHC molecules present on antigen presenting cells.
Unit 3: Antigens
Antigenicity and immunogenicity, Immunogens, Adjuvants and haptens, Factors influencing immunogenicity, B and T-Cell epitopes
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Q.What is adjuvant?
Adjuvants are substances that, when mixed with an antigen and injected with it serve to enhance the immunogenicity of that antigen. Adjuvants are often used when an antigen has low immunogenicity or when only small amounts of an antigen are available.
Effects of adjuvants are as follows:
a)Prolong antigen persistence, b)Enhance co-stimulatory signal, c)Induce granuloma formation, d)Stimulate lymphocyte proliferation nonspecifically.
Example-
Unit 4: Immunoglobulins
Structure and functions of different classes of immunoglobulin, Antigen-antibody interactions, Immunoassays (ELISA and RIA), Monoclonal antibody production
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Q.What do you mean by Fc and Fab?
The fragment crystallizable region (Fc region) is the tail region of an antibody that interacts with cell surface receptors called Fc receptors and some proteins of the complement system. This property allows antibodies to activate the immune system.
i)In IgG, IgA and IgD antibody isotypes, the Fc region is composed of two identical protein fragments, derived from the second and third constant domains of the antibody's two heavy chains; IgM and IgE Fc regions contain three heavy chain constant domains (CH domains 2–4) in each polypeptide chain.
ii)The Fc regions of IgGs bear a highly conserved N-glycosylation site.
iii)Glycosylation of the Fc fragment is essential for Fc receptor-mediated activity.
iv)The N-glycans attached to this site are predominantly core-fucosylated diantennary structures of the complex type. v)In addition, small amounts of these N-glycans also bear bisecting GlcNAc and α-2,6 linked sialic acid residues.
The antigen-binding (Fab) fragment is a region on an antibody that binds to antigens. It is composed of one constant and one variable domain of each of the heavy and the light chain. The variable domain contains the paratope (the antigen-binding site), comprising a set of complementarity determining regions, at the amino terminal end of the monomer. Each arm of the Y thus binds an epitope on the antigen.
Unit 5: Major Histocompatibility Complex
Structure and functions of MHC molecules, Structure of T cell Receptor and its signalling, T cell development & selection
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Q.Distinguish between MHC I and MHC II molecule.
Unit 6: Cytokines
Types, properties and functions of cytokines.
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Unit 7: Complement System
Components and pathways of complement activation.
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Q.Give examples of 3 initiators of the alternative pathway of complement activation.
i)Lipopolysaccharides from gram-negative bacteria, ii)Teichoic acid from gram-positive cell walls, iii)Fungal and yeast cell walls (zymosan)
Q.What is MAC?
The terminal sequence of component activation in complement system involves C5b, C6, C7, C8 and C9, which interact sequentially to form a macromolecular structure, called membrane attack complex (MAC) or terminal complement complex (TCC). This complex forms a large channel through the membrane of the target cell, enabling ions and small molecules to diffuse freely across the membrane.
Unit 8: Hypersensitivity
Gell and Coombs’ classification and brief description of various types of hypersensitivities.
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Unit 9: Vaccines
Various types of vaccines, Active & passive immunization (Artificial and natural).
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Q.Give examples of 3 common agents used for passive immunization.
