Figure 2. Desialylation of human MoDCs loaded with whole tumor cell antigens improves T cell cytotoxicity against tumor cells.

MoDCs obtained from HLA-A*02:01 donors were treated with sialidase (Sia), for 1 hour at 37°C or left untreated, and loaded with lysates of the breast cancer cell line MCF-7 (TL). Autologous CD3⁺ T cells (T) were co-cultured with MoDCs loaded with MCF-7 lysates (MoDC^TL), or MoDCs that were sialidase treated and loaded with MCF-7 lysates (MoDC^sia+TL). After 3 weeks, CD3⁺ T cells were co-cultured for 5 hours with MCF-7 cells (Tu) in a ratio of 1 Tu: 10 T cells; non-stimulated T cells were cultured with MCF-7 as control. (A., B.) T cells primed with desialylated human MoDCs loaded with MCF-7 cell lysates induce higher tumor cell apoptosis. Tumor cell death was evaluated by flow cytometry by assessing both the intensity of GFP reporter (A) and Annexin V and 7-AAD reactivity. (B) Values represent the percentage ± SEM of viable tumor cells based on the maintenance of GFP fluorescence (GFP⁺) in 4 independent assays (graph A) and the percentage ± SEM of apoptotic tumor cells assessed by staining with Annexin-V and 7-AAD, in 3 independent measurements (graph B). Statistically significant differences were calculated using t-test (*P < 0.05). C. T cells primed with desialylated MoDCs show higher degranulation. The degranulation of cytotoxic T cells against tumor cells was determined based on the CD107a expression. Representative Histogram is a representative experiment of 4 independent assays.