Characterization of somatically mutated S107 V_H11-encoded anti-DNA autoantibodies derived from autoimmune (NZB × NZW)F₁ mice

We have studied 19 S107 heavy chain variable region gene (V_H11)-encoded monoclonal antibodies from NZBWF1 mice. These studies show that a single V_H gene can encode both antibodies to foreign antigens (anti-phosphorylcholine) and to self antigens (anti-double-stranded DNA) in the same animal. All of the anti-DNA antibodies contain many somatic mutations compared with the relevant germline genes. Since the anti-DNA antibodies were extensively somatically mutated and had undergone isotype switching, the response seems to be T cell dependent. While some of the antibodies appear to be the products of an antigen-driven and antigen-selected response, a number of characteristics of the antibodies suggest that forces other than antigen are contributing to the stimulation and selection of this response.