RESUMO
AIM: To investigate the effect of R848(a Toll-like receptor 7/8 agonist)combined with poly-inosinic:polycytidylic acid [Poly(I:C),a Toll-like receptor 3 agonist] on dendritic cell(DC)maturation,and the killing effect of DC-induced cytotoxic T-lymphocytes(CTL)on human lung adenocarcinoma A549 cells.METHODS:Mononu-clear cells were isolated from human peripheral blood and induced to differentiate into DC.The whole-cell lysate of A549 cells,namely tumor cell lysate(TCL), was used as antigen.R848 combined with Poly(I:C)was used as adjuvant to stimulate the DC.DC surface markers were analyzed by flow cytometry.The DC stimulated by antigen was co-cultured with T-lymphocytes for 7 d to induce CTL.The culture supernatant and CTL were collected.The levels of interleukin-12(IL-12)p70,interferon-γ(IFN-γ)and tumor necrosis factor-α(TNF-α)in the supernatant were measured by ELISA.The CTL and A549 cells were co-cultured for 16 h,and the cytotoxicity was observed by LDH assay.RESULTS:The expres-sion of CD83 and CD80 on the DC surface,and the secretion of IL-12 p70 in DC-R848+Poly(I:C)group were significant-ly increased compared with DC-TCL group(P<0.01).In addition,the cytotoxicity of CTL for A549 cells in DC-R848+Poly(I:C)group was significantly enhanced compared with DC-TCL group(P<0.01).The secretion levels of IFN-γand TNF-αin DC-R848+Poly(I:C)group were significantly elevated compared with DC-TCL group(P<0.01).CONCLU-SION:R848 combined with Poly(I:C)significantly promotes DC maturation and activation, and enhances the antigen-presenting effect of DC and the cytotoxicity of DC-induced CTL.