Evidence that MuLV-induced thymic lymphoma cells possess specific cell membrane binding sites for MuLV.

Cell-surface binding sites specific for thymotropic murine leukemia viruses were found in high concentrations on thymic lymphoma cell lines induced by this class of virus, but were detectable in much lower concentrations (if at all) in several non-T leukemias, plasmacytomas, and normal thymocytes or spleen cells. By specific comparison, Moloney leukemia virus (M-MuLV) binds to a lymphoma induced by M-MuLV, but not to a thymic lymphoma induced by Gross leukemia virus (G-MuLV); and G-MuLV binds to an AKR lymphoma but not to the M-MuLV-induced lymphoma. The material which binds to these T-lymphoma membrane sites is input virus, rather than a contaminant which copurifies with virus. Autoradiographic analysis demonstrates that a high proportion of T-lymphoma cells possess binding sites, whereas only a rare cell in the thymus binds murine leukemia virus to the same degree. We raise and discuss the hypothesis that each T lymphoma induced by thymotropic leukemia viruses may represent the clonal descendants of the few rate cells in the normal thymocyte population which also bind these viruses.