Paired H-2-specific monoclonal antibodies react differently to red cells and lymphocytes

Two hybrid clones from a fusion of C57BL/6 anti-DBA/2 spleen cells and the myeloma line Sp2/0 secrete antibodies reactive with a product of the murine major histocompatibility complex (MHC). The two antibodies are provisionally designated S13.11 and S13.29. Both react in rabbit-complement-mediated cytotoxicity with spleen cells of H-2d, H-2f, H-2r, and H-2p strains. In addition, both antibodies hemagglutinate red blood cells from these strains. S13.11 is also cytotoxic for H-2a, H-2k, H-2u, and H-2v spleen cells but does not hemagglutinate red blood cells from mice bearing these haplotypes. With the exception of H-2v, this strain pattern mimics the public specificity H-28. Quantitative absorption of S13.11 shows that H-2d cells are twice as efficient as H-2k cells in their ability to remove the S13.11 antibody. S13.29 reacts weakly in cytotoxicity with H-2k spleen cells and does not react with cells from H-2u or H-2v. Blocking studies indicate that S13.11 and S13.29 react with the same or a closely related molecule on the cell surface.