Differences In Lymphomagenic Properties Of Akr Mouse Retroviruses

Long-term studies on lymphomagenicity of several AKR mouse retroviruses have shown that the biologically cloned ecotropic SL3-3 c virus is the most lymphomagenic of all viruses tested. This fact was demonstrated by lymphomagenicity in five mouse strains SJL, C3H f /Bi, C3H/HeJ, CBA/H, and NFS, and lymphoma acceleration in AKR mice. The incidence was higher and latent periods shorter than that found with the other retroviruses tested (SL3-1 c , SL3-2 c , MCF c , and GMuLV c ). In addition, it was the only retrovirus found to be highly oncogenic in the C3H/HeJ and CBA/H strains. Lack of lymphomagenicity of MCF c in CBA/H strain was shown to be due to a block in viral replication. Addition of nononcogenic Akv ecotropic virus did not affect this lack of oncogenicity. The lymphomas developing in CBA/H and SJL mice after neonatal inoculation of SL3-3 c virus only produced lymphomagenic ecotropic virus. Thus, SL3-3 c lymphomagenesis is most likely due solely to the action of that virus. These studies indicate that pure ecotropic AKR viruses can be highly leukemogenic.