It was well documented that the activated DCs secreted more Th1 cytokines and polarized the immune response toward a protective Th1 profile against fungal infection. DC vaccine could improve the efficiency of antigen presentation, so it has been widely used in animal models and human subjects.
This study used adenovirus as a vector for DC-SIGN gene delivery into DCs. DC-SIGN modified DCs could overexpression DC-SIGN, which was confirmed by quantitative reverse transcriptase-PCR, Western blot analysis, and fluorescent staining.
In addition, this study did not observe significant effects of DC-SIGN modified DCs on T cells proliferation, suggesting that DCs stimulating T-cell proliferation and phagocytosis might be mediated through different molecular mechanisms.
In addition, the cultured DCs might be contaminated with other cell types, such monocytes, etc.
As shown in Figure 10, when MSCs were added at day 5, the OD value after DCs stimulated T cells was 0.786 [+ or -] 0.085, which was not significantly different from that of DC only group (0.8 [+ or -] 0.056).
The present study found that, after coculturing MSCs with DCs, the expression of CD80, CD86, and MHCII on the surface of DCs decreased, and the effect of DCs on T cell proliferation was also weakened, suggesting MSCs could inhibit the maturation and function of DCs.
Gal-1 Downregulates the Expression of Costimulatory Molecules on the Surface of DCs. As shown in Figure 11, the expression of CD80, CD83, CD86, and MHC II on the surface of DCs in the MSC + DC and Gal-1 + DC groups was significantly lower than that in DC only group.
After adding TdG, the levels of IL-10 and IL-12 in the supernatants of the MSC + DC + TDG group (151.68 [+ or -] 27.06 and 177.61 [+ or -] 21.04, resp.) were significantly lower than those of the MSC + DC and Gal-1 + DC groups, suggesting that Gal-1 promoted the secretion of IL-10 and IL-12 from DCs.
Gal-1 Reduces the Proliferative Activity of T Cells Stimulated by DCs. As shown in Figure 13, the mixed lymphocyte reaction assay results showed that the DCs of the MSC + DC (OD value 0.438 [+ or -] 0.063) and Gal-1 + DC groups (OD value 0.242 [+ or -] 0.035) only slightly stimulated the proliferation of allogeneic T cells; in these two groups, the proliferation of allogeneic T cells stimulated by DCs was significantly lower than that in DC only group (OD value 0.778 [+ or -] 0.042).