Characterization of two immunoglobulin VH genes that are homologous to human rheumatoid factors.

We isolated a VH1 germline gene (Humhv1263) that is closely related to the heavy chains of 2 human rheumatoid factors (RF), Bor and Kas. We also found that the 783 rearranged VH1 gene is actually 91-93% homologous to Bor and Kas, and it differs from a VH1 complementary DNA (51P1) by only a single base. Thus, 783 is likely to be the unmutated form of a germline VH gene that may encode the heavy chains of RF Bor and Kas and several other human monoclonal RF.