H--2-linked genes control immune response to V-domains of myeloma protein 315.

Immunoglobulins function as antigen receptors of B lymphocytes and as effector molecules for elimination of foreign antigens. Recently, other functions have been revealed: for example, idiotypes (antigenic sites of variable (V) domains) bound on the surface of plasmacytomas can act as tumour-specific transplantation antigens. Moreover, optimal maturation of B lymphocytes of a given idiotype into antibody-secreting cells seems to require assistance from two different kinds of helper T cells (Th), one bearing receptors complementary or similar to that idiotype, and another that recognizes the antigen. To learn more about recognition of V regions by Th, we have used V-domains of the immunoglobulin A (IgA) (lambda 2) myeloma protein M315 produced by the BALB/c plasmacytoma MOPC315 (ref. 7) as carriers for anti-hapten responses. We report here that the Th response to the V-domain of the heavy chain (VH) and the light chain (VL) of M315 seems to be under H--2-linked immune response (IR) gene control.