Productive I nfection and Morphologic Alter- ation of Human Cells by a Modified Sarcoma Virus 1

SUMMARY-Murine sarcoma virus apparently coated with feline leu-kemia virus envelope [MSV (Fell V)] could, in association with feline leukemia virus, morphologically alter and actively replicate in various human cell cultures. New deFective MSV (Fell V) and cat leukemia virus, which could grow in both cat cells and human cells, were produced. MSV (Fell V) exhibited selective tissue tropism and required active cell growth. Human embryo cultures could be chronically inFected with either MSV (Fell V) or Fell Valone. In human embryonic lung cells, a cell-Free passage of the MSV (Fell V) virus complex could be established. Cat leukemia virus per se could also inFect productively some human cells as determined by the induction of new helper virus for deFective MSV (Fell V).-J Nat Cancer Inst 44: 429-438, 1970. VIRUSES of both the avian and murine leukemia-sarcoma groups can infect some species other than their native hosts under specific conditions (1-8)