Specificity of anti-H-2 class I antibodies induced by syngeneic immunization with Sendai virus-treated cells is regulated by the mouse MHC and viral antigens. No evidence for MHC-restricted virus-specific antibodies.

In a previous study, we searched for Sendai virus (SV)-specific antibodies that were restricted in their binding by self-major histocompatability complex (MHC) antigens. In C57BL/6 (B6; H-2b) mice, most of the sera obtained after i.p. injections with syngeneic SV-coated (SV+) spleen cells contained auto- and alloreactive lymphocytotoxic antibodies directed against H-2 class I molecules, but no viral-specific, MHC-restricted antibodies. Here we report that syngeneic immunization with SV+ cells regularly induced H-2-specific antibodies in various mouse strains. From a total of 12 strains tested, only the B10.S (H-2s) strain appeared to be a low responder. The immune responses are of two types: (i) mice of some strains produce autoreactive antibodies and a broad variety of alloreactive antibodies; and (ii) mice of some strains produce only narrow or widely alloreactive antibodies. Because most of the strains differ only in the H-2 region, the patterns observed are regulated by the MHC. To locate the genes involved in the induction of H-2-specific antibodies more precisely, two B6 mutant strains, bm1 (Kb mutant) and bm13 (Db mutant), were immunized with syngeneic SV+ cells. The results suggest that the H-2Db region plays an important role in the induction and specificity of the lymphocytotoxic H-2 class I-specific antibodies present in sera of H-2b mice after syngeneic immunization with SV+ cells. The role of SV in the induction of H-2-specific antibodies was studied in B6 mice after injections of syngeneic cells coated with liposomes bearing the F and HN proteins of SV. The results suggest that SV surface glycoproteins as well as internal proteins are directly involved in regulating the specificity of anti-H-2 antibodies present in sera after syngeneic immunization with SV+ cells. This study does not support the concept that antigen-specific, MHC-restricted antibodies are a part of the B-cell repertoire.