Effects of the thymic microenvironment on autoantibody production in (NZB X NZW)F sub(1) mice

The effects of the thymic microenvironment on autoantibody production in (NZB x NZW)F sub(1) mice were studied. Neonatally thymectomized male and female F sub(1) mice reconstituted with a parental or F sub(1)-irradiated thymic lobe were compared to nonreconstituted and sham-thymectomized controls. While maleness retarded the spontaneous production of ss-and ds-DNA antibodies, thymic grafts did not suppress antibodies to ss-DNA in either sex, but did suppress the production of antibodies to ds-DNA in female mice. A unique property of NZB thymic grafts was the inability to suppress anti-RBC antibodies in male mice. Since the administration of thymosin did not suppress autoantibody production, the effects of the thymic grafts was not solely via thymic hormone production. The studies suggest that sex hormones and/or the thymic microenvironment can exert a suppressive effect on autoantibody production and that autoantibodies differ in their susceptibility to such suppression.