Combination therapy of murine tumors with lentinan, bacterial lipopolysaccharide and a Streptococcus preparation, OK432.

Combination therapy by intralesional injection of OK432 followed by intraperitoneal administration of lentinan and bacterial lipopolysaccharide caused almost complete regression of solid-type tumor MH134. All three components were needed for maximal antitumor activity. Mice in which MH134-tumor had regressed due to this combination therapy showed an augmented antitumor delayed hypersensitivity reaction (measured by the footpad test) and resistance to rechallenge with MH134, but they had no cytolytic antibodies in their serum detectable by the complement cytotoxicity test. The possible importance of local inflammation induced by OK432 in this combination therapy is discussed.