IN-VITRO EVOLUTION OF A NEUTRALIZING HUMAN-ANTIBODY TO HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 TO ENHANCE AFFINITY AND BROADEN STRAIN CROSS-REACTIVITY

A method is described that allows for the improvement of antibody affi nity. This method, termed complementary-determining region (CDR) walki ng, does not require structural information on either antibody or anti gen. Complementary-determining regions are targeted for random mutagen esis followed by selection for fitness, in this case increased binding affinity, by the phage-display approach. The current study targets a human CD4-binding-site anti-gp120 antibody that is potently and broadl y neutralizing. Evolution of affinity of this antibody demonstrates in this case that affinity can be increased while reactivity to variants of human immunodeficiency virus type 1 is broadened. The neutralizing ability of this antibody is improved, as assayed with laboratory and primary clinical isolates of human inmunodeficiency virus type 1. The ability to produce human antibodies of exceptional affinity and broad neutralizing ability has implications for the therapeutic and prophyla ctic application of antibodies for human immunodeficiency virus type 1 infection.