Histopathology of tumor regression by cord factor, turpentine or endotoxin, dissociation of therapy and granuloma formation

Histologic changes and therapeutic effects seen after a single injection of emulsified trehalose-66'-dimycolate, a mycobacterial glycolipid, into growing dermal implants of a mouse fibrosarcoma were similar to those seen after injection of endotoxin and of emulsified turpentine. Intralesional injection of any of these agents caused the tumors to regress in a significant number of animals. The number of tumor free mice capable of resisting the growth of tumor cells in a challenge inoculum, however, was greater for animals treated with trehalose-6,6'-dimycolate than those treated with turpentine or endotoxin. Granuloma formation was not a requirement for tumor regression in this mouse model.