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A biological significance with the combination of an immunomodulator CpG-oligodeoxynucleotide (ODN) and therapeutic vaccines induced by photodynamic therapy (PDT) was examined. PDT-generated cell lysates + ODN coinjection against a cervical cancer model TC-l cells was designed in vivo, and some immune responses such as IFN-γ secretion and CTL activation by the coinjection were investigated. We found that heat shock protein 70 (HSP70) was greatly induced from the cells by PDT in vitro, that the PDT-generated tumor cell lysates were potent therapeutic vaccines and that PDT vaccines are more effective than freezing/thawing (F/T) tumor cell lysates. Moreover, PDT lysates+ODN coinjection showed a significant suppression of tumor growth at therapeutic level in tumor bearing mice. We additionally evaluated levels of immune responses by the coinjection system. IFN-γ production was significantly detected in the coinjected group, and CTL responses were also remarkably induced by PDT lysates+ODN. Taken together, these data suggest that PDT-generated therapeutic vaccines (including overexpressed HSP70)+ODN codelivery could be an effective approach to induce CTL immune responses as a possible immunotherapeutic strategy for cervical cancer.

[Proc Amer Assoc Cancer Res, Volume 47, 2006]