Viral expression in two myelomonocytic cell lines obtained from long-term bone marrow culture infected with the friend polycythemia-inducing virus (FV-P)

Abstract

Two subclones of monomyelocytic cell lines (317 and G-31), issued from mouse long-term bone marrow cultures infected with Friend polycythemia-inducing virus, were studied for virus release and viral protein expression. The 317 cell line permanently produced biologically active spleen focus-forming virus (SFFV) and expressed the gp52 SFFV which has been described as encoded by the SFFV genome. In contrast, the G-31 cell line was devoid of any SFFV expression although it released Friend helper leukemia virus (FMuLV). Both lines expressed a new gp70-related glycoprotein with an apparent molecular weight of 66,000. This gp66 species was metabolically unstable and was not packaged into viral particles nor released in culture medium. It was recognized by an anti-Rauscher gp70 antiserum but not by anti-MCF gp70 or anti-p15E antisera. gp66 was not found in erythroblastic Friend tumor cell lines, in fibroblasts infected with virus released by lines 317 and G-31, or in nonmyelomonocytic infected hematopoietic cells. However, it was constantly observed in cell lines with a myelomonocytic origin established in vivo and in vitro. Therefore, gp66 is a F-MuLV gp70-related product specifically linked to the myeloid lineage.