D H Troxler

Rapid leukemia induced by cloned friend strain of replicating murine type-c virus. Association with induction of xenotropic- -related rna sequences contained in spleen focus-forming virus.

Abstract Newborn NIH Swiss and BALB/c mice have been shown to develop a rapid splenic leukemia when inoculated with high-titered preparations of cloned Friend strain of replicating ecotropic type-C virus. Increased spleen weight can be detected as early as 21 days after injection of Friend helper leukemia virus (F-MuLV). Concomitant with the replication of F-MuLV and the development of leukemia, there is a 100- to 1000-fold increase in the spleens of levels of RNA sequences which are detectable with a spleen focus-forming virus (SFFV)-specific cDNA probe (cDNA SFFV ). Since cDNA SFFV detects RNA sequences which are derived from the env gene region of xenotropic virus, the results suggest that expression of RNA sequences highly related to xenotropic virus might be important in the pathogenesis of F-MuLV-induced leukemia.

Helper-independent and replication-defective erythroblastosis-inducing viruses contained within anemia-inducing friend virus complex (FV-A)

Abstract Helper-independent and replication-defective viruses contained within the anemia-inducing Friend virus complex have been analyzed. Helper-independent ecotropic viruses, F-MuLV, have been isolated which produce rapid hepatosplenomegaly and anemia when injected into newborn Swiss mice, but which do not cause this disease syndrome when injected into adult NIH Swiss mice. The histology of the enlarged spleens shows many erythroblasts and some areas of clear erythroid maturation in the later stages of the disease. A replication-defective virus has also been isolated which is an env gene recombinant virus and codes for a 52,000-dalton glycoprotein which has a specific immunological relationship to the gp70 of MCF murine leukemia viruses. This replication-defective virus (SFFVFV-A) shows many similarities to the previously studied replication-defective virus found in polycythemia-inducing Friend virus stocks (SFFVFV-P). However, clear differences between SFFVFV-P and SFFVFV-A also exist. Pseudotypes of SFFVFV-A cause rapid proliferation of erythroid precursors when injected into either newborn or adult Swiss mice. This disease is characterized by splenomegaly, friable spleens, normal or moderately low hematocrits, and splenic foci. Pseudotypes of SFFVFV-P also cause rapid proliferation of erythroid precursors when injected into either newborn or adult Swiss mice. This disease is characterized by splenomegaly, firm spleens and large foci, and normal or elevated hematocrits. The possible relationships between F-MuLV, SFFVFV-A, and SFFVFV-P are discussed.