Identification of novel HLA-A 0201-restricted epitopes from anterior gradient-2 as a tumor-associated antigen against colorectal cancer

Anterior gradient-2 （AGR2） promotes tumor growth, cell migration and cellular transformation and its enhanced expression is almost completely restricted to malignant tissues, thus making AGR2 an interesting target for the development of immunotherapeutic strategies. We investigated whether the AGR2 molecule comprises human leukocyte antigen （HLA）-A 0201-binding epitopes recognized by human cytotoxic T lymphocytes （CTLs）, which could be targeted in dendritic cell （DC）-based cancer immunotherapy against colorectal cancer （CRC）. We reviewed the sequence of AGR2 for peptides that could potentially bind to HLA-A 0201 with the aid of a computer-based program. Five candidate peptides with different binding scores were synthesized and tested. These peptides were then assessed for their immunogenicity to elicit specific immune responses mediated by CTLs in vitro by means of enzyme-linked immunospot assays and CTL assays. AGR2 was highly expressed in several CRC cell lines, including DK01, DLD1, KM 12C, HCT-8 and HT-29. DCs pulsed with AGR2-P2 （aa 11-19; LLVALSYTL） or AGR2-P4 （aa 127-135; RIMFVDPSL） generated potent CTLs that could lyse T2 cells pulsed with AGR2-P2 or AGR2-P4 and HLA-A0201＋ AGR2-positive CRC cell lines in a strong dose-dependent and HLA-A 0201-restricted manner. In conclusion, these novel epitopes derived from AGR2 protein may be attractive candidates for DC-based immunotherapy for CRC.

Type I and II interferons enhance dendritic cell maturation and migration capacity by regulating CD38 and CD74 that have synergistic effects with TLR agonists

The major limitation for the maturation of dendritic cells(DCs)using Toll-like receptor(TLR)agonists is their decreased ability to migrate into lymph nodes compared with conventional DCs.CD38 can be used as a multifunctional marker to modulate migration,survival and Th1 responses of DCs.CD74 has been shown to negatively regulate DC migration.The goal of this study was to investigate the combinations of TLR agonists and interferons(IFNs)that most effectively regulate CD38 and CD74 expression on DCs.Synergistic TLR agonist stimulation in combination with IFN-a and IFN-c was the best method for regulating CD38 and CD74 expression and inducing the highest secretion of IL-12p70.An in vitro migration assay showed that DCs treated with this combination had significantly enhanced migratory ability,similar to that observed in cells expressing CD38,CD74 and CCR7.The results of this study suggest that an alternative maturation protocol in which two TLR ligands are combined with type I and II IFNs generates potent DCs that have both a high migratory capacity and high IL-12p70 production.