Isolated hypervariable regions derived from streptococcal M proteins specifically bind human C4b-binding protein: Implications for antigenic variation
Antigenic variation in microbial surface proteins represents an apparent paradox, because the variable region must retain an important function, while exhibiting extensive immunological variability. We studied this problem for a group of streptococcal M proteins in which the similar to 50-residue hypervariable regions (HVRs) show essentially no residue identity but nevertheless bind the same ligan