Amino acid sequences hypervariable regions

In summary, for all the immunoglobulin molecules within one class, the amino acid sequence in the constant region of the chains is identical the massive number of different molecules within each class is accounted for by the amino acid sequences in the variable and hypervariable regions of both the light and heavy chains. 

In most Caucasian populations with rheumatoid arthritis, genetic susceptibility is conferred by HLA-DRB1 alleles that share a common amino acid sequence ( shared epitope ) in the third hypervariable region of the HLA-DRB 1 chain (amino acids 70-74 QRRAA, QKRAA, RRRAA) (Gregersen et al., 1987 Nepom,... 

FIGURE 26.2 (See color insert following page 40). The differences from a murine antibody (a) to a fully human antibody (d). In (b), the constant regions of the murine antibody have been replaced with human constant domains. In (c), the amino acid sequences adjacent to the three hypervariable regions in the variable domains had been humanized by modeling amino acid substitutions that are more commonly found in human antibodies. 

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