Figure 1. Desialylation of human MoDCs loaded with whole tumor cell antigens induces T cell activation.

MoDCs were first treated with sialidase (Sia), for 1 hour at 37°C or left untreated, followed by loading with MCF-7 lysates (TL), as source of whole tumor cell antigens. MoDCs were then used in co-cultures with autologous T cells for 4-8 days in the presence of of IL-2. A. Desialylated MoDCs show a higher induction of T cell proliferation. T cells were previously labeled with CFSE and the progeny, i.e., the percentage of T cells that proliferated, was estimated by flow cytometry, based on the CFSE dilution. The histograms show representative experiments where T cells were co-cultured with: unloaded MoDCs (panel a), MoDCs loaded with MCF-7 lysates (panel b) and sialidase treated MoDCs loaded with MCF-7 lysates (panel c). Unstimulated T cells (panel d) served as negative control and phytohaemagglutinin (PHA)-stimulated T cells (panel e) as positive control. Tabled values represent the mean percentage of proliferative cells ± SEM of 4 independent measurements. B. T cells primed with desialylated MoDCs show higher secretion of Th1 cytokines. The cytokines secreted into the co-culture supernatants, following T cell stimulation with MoDCs were measured by ELISA (n = 7). Graph values represent the concentration (pg/mL) (average ± SEM). Statistically significant differences were calculated using t-test (*P < 0.05).