title: Helper activity of human leukemic tissue extracts for leukemia virus expression in mice.
abstract: Extracts of cultured human leukemic tissues increased the spleen focus-forming activity of Friend leukemia virus preparations in BALB/c and other partially resistant mice. Such mice carry the Fv-1(b) gene, which inhibits the expression of helper virus indigenous to the Friend virus complex, and allows co-infecting leukemia viruses of mice, cats, or chickens to substitute for the inhibited helper virus and increase the expression of the spleen focus-forming virus. The helper activity of extracts from human leukemic tissues shared several important properties with that associated with known leukemogenic viruses of animals.
mesh_terms: D000818:Animals; D001773:Blood Cells / Q000382:microbiology; D001853:Bone Marrow / Q000382:microbiology; D001854:Bone Marrow Cells; D046508:Culture Techniques; D005622:Friend murine leukemia virus / Q000254:growth & development; D006378:Helper Viruses; D006689:Hodgkin Disease / Q000382:microbiology; D006801:Humans; D007938:Leukemia / Q000382:microbiology*; D009052:Leukemia Virus, Murine / Q000254:growth & development*; D007945:Leukemia, Lymphoid / Q000382:microbiology; D007951:Leukemia, Myeloid / Q000382:microbiology; D015470:Leukemia, Myeloid, Acute / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology; D016403:Lymphoma, Large B-Cell, Diffuse / Q000382:microbiology; D008228:Lymphoma, Non-Hodgkin / Q000382:microbiology; D051379:Mice; D011087:Polycythemia Vera / Q000382:microbiology; D013154:Spleen / Q000382:microbiology; D014020:Tissue Extracts; D014776:Virus Cultivation
chemical_list: D014020:Tissue Extracts