Polymorphic and autoreactive H-2-specific monoclonal antibody isolated after injections of syngeneic Sendai virus-coated lymphocytes.

An H-2-specific monoclonal antibody (mAb Q-1) was obtained from B10.Q (H-2q) mice injected with syngeneic Sendai virus-coated cells. The IgM monoclonal antibody recognizes the public determinant H-2.25 shared by H-2k (Kk) and H-2r haplotypes and cross-reacts with H-2d, H-2s, H-2p, and H-2q cells, the latter being the haplotype of the challenged B-cell donor. The binding of mAb Q-1 to H-2d, H-2s, H-2q, and H-2p cells was lower than to H-2k and H-2r and of decreasing affinity but could be clearly distinguished from the negative reactions with H-2b and H-2f cells. MAb Q-1 distinguishes between Sendai virus-coated and uncoated lymphocytes only cells with low-affinity binding. On virus-coated or infected (H-2p, H-2q, H-2d, H-2s) cells lysis was stronger than on normal lymphocytes. We interpret the enhanced lysis of Sendai virus-positive cells by mAb Q-1 to be due to recognition of a modified exposure of public H-2 determinants induced by Sendai virus.