Identification of virus found in mouse lymphomas induced by HIX murine oncornavirus

Lymphomas induced by pure HIX murine leukemia virus in two mouse strains contained large amounts of virus with amphotropic properties. Analysis of tumor derived virus purified by limiting dilution techniques indicated that its interference and neutralization spectra were essentially identical to parental HIX virus and different from eco- and xenotropic viruses. Examination of virus progeny from many individual foci induced by virus derived directly from lymphomas indicated that each infectious unit contained only HIX virus. No evidence of ecotropic virus presence was observed.