Lack of significant differences in association rates and affinities of antibodies from short-term and long-term responses to hen egg lysozyme

The affinities (K-a) and association rate constants (k(on)) of 23 mouse (BA LB/c) anti-lysozyme mAbs obtained after short and prolonged immunizations h ave been measured by plasmon resonance techniques. The affinities for the 2 3 Abs, measured using their Fab, range from K-a = 1.1 x 10(7) to 1.4 x 10(1 0) M-1. There is no significant correlation between time or dose of immuniz ation and affinity or association rates, indicating no time- or dose-depend ent maturation of the response within the doses and times that were explore d. IgMs are produced early and late in the response, with intrinsic affinit ies < 10(5) M-1. Two independently derived mAbs, D44.1 (short term) and F10 .6.6 (from a longer term response), result from identical or nearly identic al somatic recombination events of germline gene segments. F10.6.6 has more mutations and a higher affinity constant (K-a = 1.4 x 10(10) M-1) than D44 .1 (K-a = 1.1 x 10(7) M-1). Although higher affinities may result from an a ccumulation of mutations, they do not correlate with the length and dose of immunogenic challenge.