This document summarizes key concepts related to the adaptive immune response and antibodies. It defines terms like antigenicity, immunogenicity, haptens, and antigenic determinants. It describes how antigens are captured and presented by antigen-presenting cells to T lymphocytes and B lymphocytes. It also explains monoclonal and polyclonal antibody production, the primary and secondary antibody response, affinity and avidity, and how antibodies provide diversity through their variable regions.
55. The immune system creates billions of different Abs with a limited number of genes by rearranging DNA segments during B cell development , prior to Ag exposure. Mutation can also increase genetic variation in Abs Abs Diversity Heavy chain Light chain
Dendritic cells at different stages of their maturation may express different membrane proteins Immature dendritic cells express surface receptors that capture microbial antigens Mature dendritic cells express high levels of MHC molecules and costimulators, which function to stimulate T cells (skin, in the example shown, where the dendritic cells are called Langerhans cells)
(IgG subclasses are given different names in other species, for historical reasons; in mice, they are called IgG1, IgG2a, IgG2b, and IgG3.) Light chains may be lambda or kappa. The five major classes of heavy chain are IgM, IgG, IgA, IgD, and IgE. Each of these classes differ in their locations in our body and how they stimulate the innate system to remove antigen.
Three dimensional representation of the IgG molecule
Digestion of IgG with papain produces 2 identical fragments: Fab fragments, are capable of binding Ag because they contain the Ag-binding site, and a third fragment composed of H chain only. It crystallizes in the cold, hence the name: Fc fragment
lattice (l²t“¹s) n. 1.a. An open framework made of strips of metal, wood, or similar material overlapped or overlaid in a regular, usually crisscross pattern. b. A structure, such as a window, screen, or trellis, made of or containing such a framework. 2. Something, such as a decorative motif or heraldic bearing, that resembles an open, patterned framework. 3. Physics. a. A regular, periodic configuration of points, particles, or objects throughout an area or a space, especially the arrangement of ions or molecules in a crystalline solid. b. The spatial arrangement of fissionable and nonfissionable materials in a nuclear reactor. --lat·tice tr.v. lat·ticed , lat·tic·ing , lat·tic·es . To construct or furnish with a lattice or latticework. [Middle English latis , from Old French lattis , from latte , lath, of Germanic origin.] --lat“ticed adj. ag·glu·ti·na·tion (…-gl›t”n-³“sh…n) n. 1. The act or process of agglutinating; adhesion of distinct parts. 2. A clumped mass of material formed by agglutination. Also called agglutinate. 3. Linguistics. The formation of words from morphemes that retain their original forms and meanings with little change during the combination process. 4. The clumping together of red blood cells or bacteria, usually in response to a particular antibody.
K = Equilibrium constant = Association constant = Ab affinity The higher [Ag..Ab], the larger is K (the associated Ab and Ag), the higher is affinity of the Ab to the Ag.
K = Equilibrium constant = Association constant = Ab affinity The higher [Ag..Ab], the larger is K (the associated Ab and Ag), the higher is affinity of the Ab to the Ag.
Lymph node cells may be used for cell suspension in addition to spleen cells
So how much variation is possible through recombining gene fragments? Over 15,000,000 combinations of Variable, Diversity and Joining gene segments are possible. Imprecise recombination and mutation increase the variability into billions of possible combinations.
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