Wednesday, September 17, 2011

Figure 2-7 Sequence data collected from hundreds of MM patients. Variability = number of different aa found at site / frequency of most common aa Range (1 x 1 – 20 x 0.05) HV = hypervariable region CDR = complementarity-determining region FR = framework region

Yellow CDR = complimentarily determining region of the antigen binding site

Figure 2-11 Which epitope can be recognized after denaturing the protein?

Antigens with many different epitopes (most common) induce a polyclonal response.

Figure 2-4 MADGE Antibody classes or isotypes

Monoclonal antibodies

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Review Antibodies are proteins secreted by B (plasma) cells. Antibodies mediate the adaptive humoral response. An antibody molecule has a quaternary structure (H 2 L 2 ) and one plane of symmetry. Antibodies have domains. The domains are homologous: the immunoglobulin domain aka the beta barrel. The N-terminal domains are variable. All others are constant for a given isotype. The antigen binding site (V H V L ) binds to antigen epitopes. The V domains are most variable (hypervariable) at the sites that contact the epitope, the CDRs. Since most antigens have multiple epitopes, adaptive humoral responses are polyclonal. Monoclonal antibodies are made only in the lab. The Fc portion of an antibody isotype determines its function.

Figure 3-1 part 2 of 2

Ligands bind receptors R + L R L ( receptor-ligand complex ) Kd ( dissociation constant ) = [R][L] / [RL] at equilibrium Enzyme-substrate Kd = M to M Initial antibody-antigen Kd = M to M Mature antibody-antigen Kd = M to M due to affinity maturation during clonal expansion

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