Figure 6.

ATG5 is necessary for particulate antigen presentation to T cells. (a) Co/culture with control (C57BL/6 or LM) or Atg5-cKO B cells (Cr2 cre and Cd79a cre) and CFSE-stained OT-II cells were performed. Proliferation was assessed by measuring the dilution of the fluorescent signal by flow cytometry after 3 days of culture. Cells were gated on CFSE⁺ and TCRB⁺ cells and CD44 staining was performed to ensure that the decrease of CFSE staining correlated to the activation of OT-II cells. B cells are stimulated either by plate-adsorbed antigen at different concentrations (Fab’2 anti-IgM-OVAL, 10, 5, 2.5 µg/mL; on the left) or by a soluble antigen (F(ab’)2 anti-IgM-OVAL, 10 µg.mL⁻¹; on the right). (b) Percentages of proliferating cells obtained on n = 11 independent experiments (11 C57BL/6, 11 LM, 9 Cr2 cre, 6 Cd79a cre) with different conjugate concentrations (10, 5, 2.5 µg/ml for the adsorbed antigen mimic and 10 µg/mL for the soluble antigen mimic. Bars represent mean values ±SEM; **P < 0.01, *P < 0.05 paired Student t test. (c) Measurement at D15 of anti-OVAL IgM and IgG antibody titers by ELISA, in serum from animals immunized either by soluble OVAL, or OVAL-conjugated with latex beads, in the presence of alum. Each point represents individual anti-OVAL antibody titer. Bars represent the mean ± SEM. *P < 0.05 Mann-Whitney U test, no statistical difference between control mice (C57BL/6 and LM) were revealed. N = 2 to 5.