Induction and properties of syngeneic murine anti-immunoglobulin D.

High titers of autoantibodies directed to isotypic determinants of IgD were produced by inoculation of syngeneic monoclonal IgD, conjugated covalently to keyhole limpet hemocyanin, into adult or neonatal inbred mice. Anti-idiotypic antibodies were induced at the same time. The average affinity of the mouse antibodies (Ka approximately equal to 10(7) M-1) is similar to that of rabbit anti-IgD and of syngeneic anti-IgE induced by the same procedure. Results indicate that B cells of the mice are not tolerant to serum IgD and that tolerance is maintained at the level of T cells. Direct interaction of the syngeneic anti-IgD with cell-surface IgD was minimal, and there was no convincing evidence that cell-surface IgD was down-regulated in the anti-IgD-producing mice. Further studies, preferably employing monoclonal anti-IgD, are required to determine whether epitopes on cell-surface IgD can be recognized by syngeneic anti-IgD. The ability to generate in vivo high titers of anti-IgD should facilitate the production of such monoclonal antibodies.