Tumor antigen pulsed dendritic cells enhance the cytolytic activity of tumor infiltrating lymphocytes in human hepatocellular cancer

Objective: Tumor infiltrating lymphocytes (TILs) stimulated with interleuki n -2 (IL-2) ex vivo have been successfully used therapeutically in some can cer patients, but their potency in eliciting an effective anti-tumor respon se is variable. We have tried to augment killing activity of tumor infiltra ting lymphocytes derived from hepato- cellular carcinoma (HCC) using autolo gous monocytes derived dendritic cells. Methods: Tumor infiltrating lymphoc ytes (TILs) from 6 patient with hepatocellular carcinoma were isolated and the phenotype were further characterized. From the same patients, autologou s dendritic cells were generated from CD14(+) monocytes that were cultured for days in the presence of granulocyte macrophage colony-stimulating facto r (GM-CSF) and interleukin 4 (IL-4). Those professional antigen presenting cells were pulsed with whole autologous hepatoma tumor lysates (pDC). TILs were cocultured with pDC or unpulsed DC. To assess the cytotoxic potency of TILs, the ability to lyse the tumor cell targets K652, Daudi and an alloge neic HCC celline was determined in a standard cytotoxic assay. Results: Tum or cells targets in vitro are poorly lysed by tumor infiltrating lymphocyte s indicating T-cellhyporesponsiveness. In contrast, the killing activity of HCC derived TILs against Daudi (9, 15% +/- 7,5) and allogeneic HCC tumor t arget (18,2% +/- 9,2) could be significantly augmented when stimulated with pDC (Daudi: 38% +/- 6,8 and allogeneic HCC: 55% +/- 10). The killing activ ity of TILs against K562 was unaffected by pDC. Conclusion: The low cytotox ic activity profile of HCC derived TILs in vitro can be increased by tumor lysate pulsed dendritic cells and may therefore be more effective in vivo w hen used for adoptive immunotherapy.