Transformation of histocompatibility immunogen into a tolerogen.

H-2 antigens on spleen cell membranes absorb antibody to H-2 antigens and induce both humoral and cellular responses. Liver cell membrane H-2 antigens by contrast also absorb antibody but do not influence cellular response and are tolerogenic for the humoral response. This paper demonstrates that syngeneic liver cells contain a substance which can transform the properties of allogeneic spleen cell membranes into those of allogeneic liver cell membranes, i.e., transform a humoral immunogen into a humoral tolerogen. The process appears to be accompanied by cleavage of an antigen component from the spleen membrane and hence to result in a structural change in the H-2 antigen.

Increased synthesis and expression of H-2 antigens on thymocytes as a result of radiation leukemia virus infection: a possible mechanism for H-2 linked control of virus-induced neoplasia.

Previous studies from this laboratory have mapped resistance and/or susceptibility to radiation-induced leukemia virus (RadLV)-induced neoplasia to the H-2D region. H-2 linked effects on virus replication can be detected subsequent to the initial virus infection, and clear-cut differences in numbers of virus infected thymus cells can be detected as early as 5 wk after RadLV inoculation. Rapid increases in cellular synthesis and cell surface expression of H-2 antigens are detectable immediately after virus inoculation. These changes have been studied by immunofluorescence, absorption, cell surface iodination followed by sodium dodecyl-sulfate-polyacrylamide gel electrophoresis, and two dimensional gel electrophoretic analysis of internally labeled lymphocyte proteins. Expression of H-2K molecules is significantly increased in cells of susceptible and resistant animals. However, significant increases in expression of H-2D antigens occurs only on thymus cells from resistant strains (H-2Dd). Transformed cells of resistant and susceptible H-2 haplotypes adapted to tissue culture lack detectable H-2 antigens as determined by serological absorption studies. It is argued that altered expression of H-2 antigens plays a very significant role in the mechanism of host defense to virus infection.