Antigen-specific helper factor reacts with antibodies to human beta  2 microglobulin.

Abstract

Antigen-specific helper factor was induced in vitro from lymphoid cells of monkeys and mice by using an antigen derived from Streptococcus mutans. Helper activity was removed from supernatants of monkey cells by affinity chromatography on Sepharose 4B insolubilized antibodies specific for human beta  2-microglobulin (H beta  2M) prepared in chicken, rabbit and rat, and an insolubilized monoclonal mouse anti-H beta  2M antibody-bound monkey helper factor activity. However, guinea pig antibody to human beta  2M was inactive. In parallel studies, the pattern of absorption of mouse helper factor (HF) was different from that of the monkey in that insolubilized guinea pig anti-H beta  2M bound helper factor, whereas rabbit and monoclonal anti-H beta  2M failed to do so.Although these findings were not compatible with an intact beta  2M chain being present in helper factor, they may imply a cross-reactivity of beta  2M with a "constant region" of helper factor that may share common sequences with beta  2M. This may suggest that factor genes have evolved from the same ancestral genes as beta  2M.