A new class of murine leukemia virus associated with development of spontaneous lymphomas

Abstract

A new type of murine leukemia virus was detected in thymuses of leukemic and late preleukemic AKR mice, in lymphomas developing in NIH Swiss mice carrying the AKR ecotropic virus inducing loci Akv 1 or Akv 2, and in the thymus of a preleukemic C58 mouse. The viruses induce focal areas of morphologic alteration in a mink lung cell line and are tentatively referred to as 'mink cell focus inducing' (MCF) strains. They have the host range of both xenotropic and N tropic ecotropic murine leukemia viruses, are neutralized by antisera to both ecotropic and xenotropic viruses, and are interfered with by both viruses. They may represent a particular type of genetic recombinant which emerges durin the preleukemic period in high ecotropic virus mouse strains, and they may play a significant role in the etiology of spontaneous lymphomas.