IMMUNO 440 Lecture Notes - Lecture 3: V(D)J Recombination, Frank Macfarlane Burnet, Stem-Loop
Document Summary
Large (150 kda) heterodimeric protein; 2 heavy chains (50 kda each) and 2 light chains (25 kda each) Heavy chains linked together by disulfide bonds, each heavy chain linked to light chain by disulfide bond. Each heavy chain identical, each light chain identical. Papain digestion: fab fragments (fragment antigen binding) & fc; each fragment monovalent. Pepsin digestion: fc fragment (fragment crystallizable) & f(ab")2 fragment bivalent. Mercaptoethanol reduction: h chains and l chains. Antibody molecule has 2 chains or 2 chains; no known functional differences between these. Five heavy chain classes (isotypes): ab class defined by heavy chain usage: Heavy chain usage determines effector function of antibody beyond the antigen specificity. Two important structural: each heavy and light chain composed of a series of similar sequences ~110 a. a. long called immunoglobulin domains: 2 per light chain, 4-5 per heavy chain, amino-terminal sequences vary greatly between antibodies. Light chain consists of 1 variable domain (v-domain) and 1 constant domain (c- domain): vlcl.
