Isolation of infectious DNA from avian myeloblastosis virus transformed leukemic cells.

Chide helper factor (chf) negative chick embryo cells were exposed in the presence of DEAEdextran to chromosomal DNA isolated from avian leukemic myeloblasts which had been induced by infection with the BAI-A strain of avian myeloblastosis virus (AMV) (subgroup B ). After several transfers, avian C-type virus production was observed in the cultures with electron micro­ scopy, although no alteration in the cell morphology was apparent. Virus interference tests revealed that this virus was infectious and belonged to subgroup B of the avian RNA toumor virus (ATV) group. The virus induced nephroblastomas 2 months after intraperitoneal inoculation of chickens; no myeloblastosis was observed, however, and the virus could neither transform chick embryo cells in vitro nor induce wing web tumors in vivo. The nephroblastomas also produced virus which was again shown to be a member of subgroup B. From these results it was concluded that the virus transmitted in these experiments was avian myelo­ blastosis associated virus (MAV), an avian leukosis virus known to be present as a major com­ ponent in AMV stocks.