The oncogenic effects of nontransforming viruses from avian myeloblastosis virus.

Standard avian myeloblastosis virus (AMV), BAI strain A, causes myeloblastosis, osteopetrosis, lymphoid leukosis, and nephroblastoma in chickens. In this investigation, several leu kosis viruses of subgroups A and B were isolated (rom standard AMV and characterized. A subgroup A virus derived from an AMV-induced lymphoma of a Japanese quail was isolated, and it induced a high incidence of osteopetrosis when injected in travenously into eleven-day-old chick embryos. A subgroup B virus was obtained which also induced a high incidence of osteopetrosis in chickens. These results indicate that viruses from two subgroups can induce osteopetrosis. Another strain derived from a quail rhabdomyosarcoma caused a high inci dence of lymphoid leukosis. This strain also induced a low incidence of nephroblastoma and osteopetrosis. A subgroup A strain of standard AMV was obtained without passage through the Japanese quail which had an oncogenic spectrum consist ing of osteopetrosis, nephroblastoma, and lymphoid leukosis. Leukemia was never observed in any of the birds injected with the virus strains derived from standard AMV. None of the viral isolates induced the malignant transformation of hematopoietic tissue in vitro. All of the strains derived from quail tumors were of the A subgroup of avian leukosis viruses. All subgroup A isolates demonstrated immunologie cross-reactivity. The subgroup B isolates demonstrated similar cross-reactivity but did not crossreact with any of the subgroup A viruses. The results of this study indicate that the oncogenic role of nontransforming viruses present in standard AMV is to induce osteopetrosis, nephroblastoma, and lymphoid leukosis.