The role of low affinity antibody in immune complex disease. The quantity of anti-DNA antibodies in NZB/W F1 hybrid mice.

The level and avidity of anti-DNA antibody in the serum of New Zealand Black/White (NZB/W F1) hybrid mice has been determined. The results show that there is an age and sex-related variation in the avidity of this antibody. In mice of both sexes, the avidity of circulating anti-DNA antibody increases up to 5 months of age; thereafter the avidity falls with increasing age. These variations are more marked in males, but female mice consistently have lower avidity anti-DNA antibody than males. Thus the time of onset, time course and severity of the murine lupus syndrome in NZB/W F1 mice are associated with the presence of increasing levels of low avidity anti-DNA antibody in the serum. These results are discussed in the context of the possible role of low avidity antibody in immune complex disease.