Typing of murine cell-surface antigens by cellular radioimmunoassay.

A cellular radioimmunoassay utilizing 125I-labelled Protein A was used for detecting antigen-antibody complexes on glutaraldehyde fixed cells attached to microtiter plates. This method is rapid, sensitive and specific for revealing H-2 private and public specificities as well as Ia and Lyt antigens. As plates may be kept for months, several reactivities can be tested in one step on a large panel rendering a regular supply of animals unnecessary.

Immune response genes control T killer cell response against Moloney tumor antigen cytolysis regulating reactions against the best available H-2 + viral antigen association.

Cytolytic T lymphocytes (CTL) specific for the virus-induced and leukemia-associated Friend, Moloney, Rauscher (FMR) antigen are easily detected in the spleens of primary and secondary stimulated H-2b or H-2d mice. They react, respectively, with H-2Db + FMR and H-2Kd + FMR; Dd and Kb never being involved. On the other hand, recombinant (KbDd) mice are relatively low responders that produce CTL only after secondary stimulation. Competition and blocking experiments with monospecific anti-H-2 antibodies have demonstrated that on the same H-2b tumor cells, C57BL/6 (H-2b) lymphocytes recognize Db + FMR, whereas B10.A(5R) lymphocytes recognize Kb + FMR, the restriction cannot, therefore be explained by a specific association of viral molecules with certain H-2 products. The CTL response of (B10 X 5R)F1 hybrids is (a) easily detected in primary reaction, the high responder anti-FMR phenotype being dominant and (b) directed against Db + FMR, F1 mice being low responder against Kb + FMR like the B10 parent. These results suggest that a D region-associated immune response gene controls the cell-mediated anti-FMR reaction, the best available H-2 + FMR antigenic association being chosen by CTL precursors.

Exclusive involvement of H-2Db or H-2Kd product in the interaction between T-killer lymphocytes and syngeneic H-2b or H-2d viral lymphomas.

It was demonstrated previously that the cytolysis of murine viral lymphoma cells by anti-murine sarcoma virus (MSV) syngeneic T-killer lymphocytes was restricted by some products of the H-2 complex. The respective role of the products of different regions of the H-2 complex were studied with six H-2(b) and three H-2(d) lymphomas induced by five different type C viruses. They were tested in a classical chromium release test against anti-MSV T-killer cells obtained from different inbred strains of mice, including several H-2 recombinants. Tumors o pound the H-2(b) haplotype were lysed only when effectors and target cells have in common the D(b) region. On the contrary an identity limited to the K end of the H-2 complex is necessary and sufficient in the H-2(d) haplotype. An in vitro restimulation of the spleen cells with concanavalin A strongly increased the activity of in vivo-primed T lymphocytes but did not provide any response for in vivo-primed but nonresponder cells. Preincubation of the tumor cells with anti-H-2 sera abolished the lysis by syngeneic anti-MSV effector lymphocytes. The same results were obtained by preincubating the H-2(b) targets with anti-H-2D(b), or the H-2(d) target with anti-H-2K(d). Preincubation with anti-H-2K(b) or anti- H-2D(d) were ineffective. These results show that the T-killer/target cells interaction in the MSV system involved some products of the H-2 complex which might be different with the various H-2 haplotypes and could possibly vary according to the antigenic specificity. A specific association of a viral product with a normal cellular structure, directed by the H-2 region during the viral budding could explain the observed results.