Treatment of transplanted murine tumors with an oncolytic virus and cyclophosphamide

Effective treatment of transplanted murine mammary tumors with an oncolytic virus and cyclophosphamide is reported. The oncolytic virus was cultured initially from a murine ascites tumor that had undergone "spontaneous" regression. This virus used alone causes rapid lysis of ascites tumors, but successful treatment of solid tumors requires the addition of cyclophosphamide. The virus must be injected directly into the tumor. The virus causes no detectable disease in mice even when administered in conjunction with cyclophosphamide. Fluorescent antibody techniques revealed that all A/S stock mice have antibody against cells infected with this virus.