Induction of Potent Antigen-specific Cytotoxic T Cell Response by PLGA-nanoparticles Containing Antigen and TLR Agonist

Abstract

Previously we showed that biodegradable nanoparticles con-taining poly-IC or CpG oligodeoxynucleotide (ODN) togeth-er with ovalbumin (OVA) were efficient at inducing MHC-re-stricted presentation of OVA peptides in dendritic cells. The CTL-inducing activities of the nanoparticles were examined in the present study. Nanoparticles containing poly-IC or CpG ODN together with OVA were prepared using bio-degradable polymer poly(D,L-lactic acid-co-glycolic acid), and then were opsonized with mouse IgG. The nanoparticles were injected into the tail vein of mice, and 7 days later the OVA-specific CTL activities were measured using an in vivo CTL assay. Immunization of mice with the nanoparticles con-taining poly-IC or CpG ODN together with OVA elicited po-tent OVA-specific CTL activity compared to those containing OVA only. In accordance with these results, nanoparticles containing poly-IC or CpG ODN together with OVA exerted potent antitumor activity in mice that were subcutaneously implanted with EG7.OVA tumor cells. These results show that encapsulation of poly-IC or CpG ODN together with an-tigen in biodegradable nanoparticles is an effective approach for the induction of potent antigen-specific CTL responses in vivo. [Immune Network 2013;13(1):30-33] Induction of robust cytotoxic T lymphocyte (CTL) responses is essential for the immunotherapy against cancers or viral infections. Naïve CD8 T cells become activated when their receptors recognize antigens presented by professional anti-gen presenting cells in the context of MHC-I molecules (1).