[In Vivo Antigen Delivery to Dendritic Cells-A Novel Peptide Vaccine for Cancer Therapy].

Tumor-derived peptides can induce antitumor cytotoxic T lymphocyte(CTL)response. However, the effects are limited. We aimed to overcome this limitation by selectively delivering antigen peptides to an XC chemokine receptor 1-expressing dendritic cell subset(XCR1+DC)that is notable for its exceptional ability to generate CTL response. To do that, we designed a vaccine(mXCL1-OVA peptide vaccine)that consisted of a murine XCR1 ligand(XCL1)and an ovalbumin(OVA)-derived MHC class I-restricted antigen. When co-injected with the immune adjuvant polyinosinic-polycytidylic acid(poly[I: C]), mXCL1-OVA peptide vaccine showed much greater antigen-specific cytotoxic T cell(CTL)response than either OVA protein plus poly(I: C)or OVA peptide plus poly(I: C). Furthermore, mXCL1-OVA peptide vaccine plus poly(I: C)showed more prominent antitumor effects against OVA-expressing melanoma(B16-OVA)than other vaccines with regard to growth inhibition. Thus, our results suggest that chemokine-directed antigen delivery to DC subsets with high CTL-inducing ability is a promising method for generating effective antitumor immunity.