Enhancement of immunity against murine syngeneic tumors by a fraction extracted from non-pathogenic mycobacteria

Abstract The data reported here demonstrate that a preparation extracted from nonpathogenic mycobacteria such as Mycobacterium smegmatis and hereafter referred to as interphase material protected mice against Ehrlich ascitic carcinoma, L-1210 leukemia, and another syngeneic lymphoid leukemia. Furthermore, mice treated by this preparation were much less susceptible to endotoxins than when stimulated by BCG (bacillus Calmette-Guerin) or M. smegmatis cells. Moreover, guinea pigs treated by interphase material administered in Freund's incomplete adjuvant showed an increased immune response, yet their sensitivity to tuberculin was much weaker than that of controls sensitized with Freund's complete adjuvant. Finally, resistance to Columbia SK virus infection could be demonstrated when interphase material was administered to mice prior to virus challenge.