Studies on Murine Leukemia2

This is the authors' abstract. We don't add key points for this paper.

A virus capable of inducing leukemia in rodents is described. The agent, morphologically similar to other murine leukemia viruses, induced lymphoid leukemia in a variety of mouse strains and in Osborne-Mendel rats. Although leukemogenic activity was inversely proportional to age, Swiss mice up to 6 months of age could be infected. Measurable inactivity could be demonstrated after exposure to 56° C for up to 1 hour. Virus was inactivated by formalin and ethyl ether. The virus could be propagated in cell cultures of mouse embryo without cytopathogenicity. Comparison with Moloney leukemia virus by the cell-specific antigen technique suggested antigenic differences. Cytotoxicity tests indicated that, unlike the Friend, Moloney, Rauscher, and Gross viruses, the virus described here shared cytotoxic antigens with all the other four. Vaccines prepared with this or Friend virus protected mice from the leukemogenic activity of this virus. Low concentrations (1:256) of antisera prepared against this virus neutralized high titers of virus. Cross reactivity with Moloney, Friend, and, to a lesser extent, Rauscher virus was observed. The current status of the relationship between the murine leukemia viruses is discussed.