Vaccination with B16 tumor cell lysate plus recombinant Mycobacterium tuberculosis Hsp70 induces antimelanoma effect in mice.

Tumor cell lysate (TCL) has an advantage of containing an extensive repertoire of tumor antigens but requires proper adjuvants to enhance its immunogenicity when used as an efficient tumor vaccine. Mycobacterium tuberculosis-derived heat shock protein 70 (TBHsp70) has been shown to assist crosspresentation of exogenously applied tumor antigens and activate innate immunity against tumor cells. In this study, TBHsp70-B16TCL, a preparation generated by mixing recombinant TBHsp70 and TCL of B16 melanoma cells directly, was tested for its immunogenicity as a tumor vaccine. The TBHsp70-B16TCL induced a significant inhibition of the growth and metastasis of B16 melanoma in mice and prolonged the survival of B16 melanoma-bearing mice. The inhibition was correlated with the specific immune responses induced by TBHsp70-B16TCL. The data suggest that recombinant TBHsp70-adjuvanted TCL might be developed into effective tumor vaccines for melanomas and possibly for other tumors.