Effects of Sema3A derived from tumor cells on functions of dendritic cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of tumor cell-derived Sema3A on the immunological functions of murine dendritic cells (DCs).</p><p><b>METHODS</b>Lung adenocarcinoma A549 cells were transfected with small interference RNA, Si-Sema and Si-mut, and the interference efficiency was determined by real-time PCR and Western-blot. The concentrated supernatants from cultured tumor cells, Si-Sema and Si-mut-infected tumor cells were subjected to DCs respectively. The immunophenotypes of DCs were analyzed by flow cytometry, the production of IL-12P70 and the ability of DCs to stimulate DO11. 10 T cells secreting IFN-gamma and IL-2 were detected by enzyme linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>Knockdown with Si-Sema3A significantly decreased the secretion of Sema3A by A549 cells in comparison with the Si-mut cells. DCs exposed to supernatants from Si-Sema cells showed elevated levels of MHC, CD40 and CD80, more production of IL-12P70, and enhanced capability of activating antigen-specific T cells, as evidenced by the remarkably increased levels of IFN-gamma and IL-2.</p><p><b>CONCLUSION</b>A549 cells secrete Sema3A to inhibit the maturation and functions of DCs, which might be associated with the unidentified mechanism of immune evasion by tumor cells.</p>

Adjuvant effect of co-stimulatory molecule CD137L on cellular responses to HBsAg DNA vaccination in mice / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the adjuvant effect of co-stimulatory molecule CD137L on cellular responses to HBsAg DNA vaccination in mice.</p><p><b>METHODS</b>Eukaryotic expression vector containing the full length of mouse CD137L cDNA sequence (pcD137L) was transfected into NIH3T3 cells, and then the expression of CD137L mRNA and protein in the transfected cells were detected by RT-PCR, flow cytometry and immunofluorescence method, respectively. The BALB/c mice were co-immunized with pcD137L and HBsAg DNA vaccine (pcDS) by intramuscular injection. HBsAg-specific activity of splenic cytotoxic T lymphocyte (CTL) in the immunized mice was measured by LDH release assay. The splenic memory CD8+ T cells, and intracellular IFN-gamma and IL-4 of splenic lymphocytes and CD8+ T cells after immunization were detected by flow cytometry.</p><p><b>RESULTS</b>The NIH3T3 cells transfected with pcD137L efficiently expressed mouse CD137L mRNA and protein. HBsAg-specific CTL responses induced by the pcDS plus pcD137L group were much stronger than those induced by pcDS alone at a week after immunization (P<0.05). Compared to mice immunized with pcDS alone, CD44high and CD127(IL-7R) were all significantly up-regulated in memory CD8+ T cells from the mice immunized with pcDS combined CD137L both at a week and 12 weeks after immunization (P<0.05 and P<0.01). The pcDS plus CD137L group also elicited higher levels of IFN-gamma secreted by CD8+ T cells and splenic lymphocytes than pcDS alone at a week, 12 and 13 weeks after immunization, respectively (all P<0.01).</p><p><b>CONCLUSION</b>DNA, viral/immunol; Co-stimulatory molecule CD137L can enhance the Tc1 (type I) cell-mediated immunity, HBsAg-specific CTL and memory responses induced by HBsAg DNA vaccine, and may be an efficient adjuvant in priming HBV-specific T cell response.</p>