Therapy of transplanted lymphomas

Allogeneic cells or cell products containing murine leukemia virus were effective in curtailing growth of a transplanted CBA lymphoma, which was originally induced by Gross virus and then maintained by syngeneic cell passage. All allogeneic cells or products effective in therapy of this lymphoma expressed virus as tested by the XC cell in vitro infectivity assay. Some of the materials also expressed virus as assayed by oncogenicity in vivo. A therapeutic effect was not demonstrated with allogeneic cells or cell products laking these virus activities. Syngeneic lymphoma cells were ineffective. Protected animals did not develop lymphoma when rechallenged several months later. Mechanisms for this therapy with virus were proposed.