Immunological regulation of spontaneous antibodies to DNA and RNA. III. Early effects of neonatal thymectomy and splenectomy

NZB/NZW F 1 (B/W) mice were subjected to sham surgery or neonatal thymectomy and/or splenectomy and studied for immunoglobulin class of antibodies to double stranded DNA and polyadenylic acid (Poly A) at 1 and 2 months of age. These antibodies occur spontaneously during the course of autoimmune disease in B/W mice. The serum from sham-operated female mice bound DNA predominantly in the 7S fraction, whereas serum from sham-operated male mice bound DNA primarily in the 19S fraction. Antibodies to Poly A were exclusively 19S in both sexes. Thymectomy of male B/W mice caused an increase in 7S and 19S antibodies to DNA at the ages studied, while it increased 19S antibodies to DNA in female mice only at 1 month of age. Thymectomy increased the 19S antibodies to Poly A in both sexes. Splenectomy had similar effects in males and females. It reduced both the 19S and 7S responses to DNA and the 19S response to Poly A at 1 month. By the second post-operative month, both 7S anti-DNA and 19S anti-Poly A antibody responses had recovered. Combined thymectomy and splenectomy of male B/W mice produced a disproportionate increase in 7S antibodies to DNA, while the procedures resulted in a decline in 7S and 19S antibodies to DNA in female B/W mice. These results suggest that the newborn (B/W) thymus and spleen contain regulatory cells exerting different controlling influences on spontaneous antibodies to DNA and Poly A. Moreover, they suggest that the male thymus exerts a suppressor influence while the female thymus exerts primarily a helper effect.