To prepare the CytoMPS-related in situ vaccine (CytoMPS-ISV) and observe its protective and therapeutic antitumor effects in treatment of mice hepatoma.

Three times of intratumoral injection of CytoMPS in C57BL/6J mice subcutaneous hepatoma were performed, and the tumor growth and mice survival rates were observed. The proportions of peripheral blood lymphocytes were detected by FACS. The killing efficacy of cytotoxic T lymphocytes(CTLs) derived from spleens of CytoMPS-ISV vaccinated mice was evaluated with and without antibody-blocking preparation. Extent of tumor-infiltrating CD4+、CD8+ and NK1.1+ cells were also detected with immunohistochemical stain(IHC).

Compared with the control group, the tumor growth in CytoMPS-ISV group was significantly inhibited(P<0.01). Moreover, the proportions of CD4+, CD8+ T cell and natural killer cell (NK) in peripheral blood in CytoMPS-ISV group were significantly higher, so were those of tumor-infiltrating lymphocytes in CytoMPS group. Compared with those in the control groups, the cytotoxicities of splenic CTL in CytoMPS-ISV group were significantly enhanced, which could be blocked by anti-mouse MHC Class I and anti-mouse CD8 antibody, but not by anti-mouse MHC Class II and anti-mouse CD4 antibody.

CytoMPS-ISV can significantly inhibit tumor growth and induce anti-tumor immunity. The killing efficacy of CytoMPS-ISV-induced CTLs is related to CD8+ T cells restricted by MHC-I.