In vitro induction of continuous acute promyelocytic leukemia cell lines by Friend or Abelson murine leukemia virus

Abstract

S INCE THEIR DISCOVERY in the 1950s’ the murine type-C RNA leukemia viruses (retroviruses) have been intensively studied as model etiologic agents for human leukemia.2’3 The biochemical mechanism for replication and integration ofviral genetic sequences into host cell DNA has been partially elucidated,3 and the proviral DNA sequences for multiple copies of leukemogenic viral genomes have been detected by sensitive molecular biologic techniques in the DNA of mouse embryo cells.3’4 Both virus-specific and host-specific genetic factors are known to be very important for leukemogenesis in vivo.”3 The recent discovery of vertically transmitted (“inherited”) viral genomes that can be induced to produce a distinct class of xenotropic viruses incapable of growth in host cells has uncovered new variables for analysis of why some viruses cause leukemia and others do not.5 In vivo studies of the cellular biology of virus-induced leukemias have been complicated by several variables: the host’s immune response to the virus, which may contribute to or even provide the target cells for transformation;6’7 the presence