Objective: To investigate whether dendritic cells pulsed with whole tumor lysates (WTL) could in vitro elicit antitumor T cell responses in patients with non-small-cell lung cancer (NSCLC).
Methods: Monocyte-derived immature DCs (imDCs) generated in the presence of human recombinant granulocyte-macrophage colony stimulating factor and interleukin-4 from peripheral blood mononuclear cell of NSCLC patients, and then were induced to mature by pulsing autologous WTL (DCs/WTL) or by the addition of TNF-alpha(TNF/DCs). FACS and MLR assay were used to monitor their phenotypic changes and capacity to stimulate allogeneic and autologous T cell proliferation. DCs/WTL activated with TNF-alpha (* DCs/WTL) were cocultured in vitro with autologous T cells for eliciting antitumor CTLs. T cell mediated antitumor responses were measured by IFN-gamma enzyme-linked immunospot (ELISPOT) assay for WTL-specific IFN-gamma releasing T cells and by lactate dehydrogenase release (LDH) assay for lysis of autologous tumor cells, respectively.
Results: When monocytes-derived imDCs from the patients with NSCLC (n = 10) were pulsed with autologous WTL for a day at 30 microg total protein of WTL per 10(6) DCs/ml, this led to up-regulation of CD1a, CD83 and CD86 as well as HLA-DR, and also led to marked stimulation of allogeneic T cell proliferating activity, which was comparable to that of TNF/DCs. However, their capacity of stimulating autologous T cell proliferation in vitro was significantly more potent than those of TNF/DCs (P < 0.05). The numbers of WTL-specific IFN-gamma releasing T cells in 1/3 cultures after one week exposure to * DCs/WTL was increased significantly compared with those pulsing with TNF/DCs plus IL-2 or IL-2 alone (P = 0.05). T cells derived by priming of non-adherent PBMCs with * DCs/WTL after 14 days in vitro stimulation were significantly more responsive to autologous tumor cells compared with LAK (n = 3, P < 0.05), but its cytotoxicity against K562 cells was also comparable to LAK cells.
Conclusion: Monocyte-derived DCs from NSCLC patients could serve as functional APC. The * DCs/WTL may effectively elicit T cell-mediated antitumor response in vitro and enhance NK killing activity.