Oncogenic and immunogenic potential of cloned HIX virus in mice and cats.

Abstract

Many naturally occurring and laboratory derived strains of murine leukemia viruses (MuLV) have been isolated. These have initially been ecotropic in host range in that they grew in mouse cells and produced lymphoid neoplasms in mice or rats (Gross, 1951, Friend, 1957, Moloney, 1960). Other classes of murine retroviruses have also been isolated from mouse cells which share a great deal of nucleic acid homology and antigenic determinants with MuLV; these have been labeled according to host range into "xenotropic" if they were restricted from growth in mouse cells or "amphotropic" if they had a host range encompassing both mouse cells and cells of other species (Levy, 1973, Aaronson and Stephenson, 1973; Benveniste et al., 1974; Hartley et al., 1976). Xenotropic viruses are not known to be oncogenic. Recently several unusual variants of MuLV type viruses with amphotropic properties have been isolated which appear to be hybrids (recombinants) of MuLV's and murine xenotropic virus (MuX) (Fischinger et al., 1975, Hartley et al., 1977). One of the isolates, MCF, was isolated from AKR lymphomas and was implicated as possibly the oncogenic virus causative of the AKR mouse lymphoma (Hartley et al., 1977). Our isolate, named HIX (hybrid of IC-strain of Moloney MuLV and MuX), has been tested now for almost two years for oncogenicity in several species because of its amphotropic host range. It was of interest to determine whether HIX virus, cloned by three cycles of limiting dilution isolation, was able to cause neoplasms in various species. The present report shows the induction of lymphomas by HIX virus in mice as well as the reisolation of only HIX virus in pure culture from these tumors. Despite growth of HIX to high titers in cat embryo cells, HIX virus inoculated newborn kittens have not shown any signs of disease.