Immunochemotherapy of hepatoma in rats

Immunoglobulin G prepared by immunization of rabbits with rat Novikoff ascites tumor cells was prepared and found to by cytotoxic to Novikoff cells and rat lymphocytes. A chlorambucil conjugate was prepared and found to have similar qualities in vitro. Three day culture systems were prepared with various test substances and the immunoglobulin was shown to markedly depress cell multiplication. The chlorambucil conjugate appeared to be more efficacious than the immunoglobulin alone in inhibiting cell growth. In vivo studies revealed a total inhibition of tumor formation in animals treated with the immunoglobulin-chlorambucil conjugate whereas all control groups had 50 to 100 per cent mortality. No systemic toxicity was apparent. These studies indicate that tumor-specific immunoglobulin bound to chlorambucil presents a feasible method of delivering tumoricidal drugs to cancer in body cavities and of treating tumors with an accessible blood supply.