HUMAN (HLA-A AND HLA-B) AND MURINE (H-2K AND H-2D) HISTOCOMPATIBILITY ANTIGENS ARE CELL-SURFACE RECEPTORS FOR SEMLIKI FOREST VIRUS

The proteins coded for by the HLA-A and HLA-B loci in man and the H-2K and H-2D loci in mice were identified as cell surface receptors for Semliki Forest virus. This conclusion is based on the following observations: Watersoluble octamers of viral coat proteins inhibit the complement-dependent cytotoxicity of antibodies directed against H-2K and H-2D antigens in mouse cells. Isolated detergent-soluble HLA-A and HLA-B antigens reconstituted in lipid vesicles inhibit the binding of viral proteins to human cells (as do the water-soluble antigens to a lesser extent). Reconstituted HLA-A and HLA-B vesicles interact in solution with Semliki Forest virus (or with vesicles containing viral spike proteins), as demonstrated by coprecipitation with antisera. Complexes between viral spike proteins and HLA-A and HLA-B antigens or H-2K and H-2D antigens can be isolated from the cell surface by utilizing affinity chromatography or immunoprecipitation.