Figure 3.

Omega-1–pulsed DCs promote Th2-type responses in vivo. BALB/c mice were injected s.c. with BMDCs unstimulated or incubated overnight with 30 µg/ml SEA, 2 µg/ml omega-1, or irradiated T. gondii (RH strain) tachyzoites (1:1). 1.5 × 10⁶ popliteal LN cells/ml from individual animals (n = 3) were pooled by mixing equal numbers of cells from each animal within a group and stimulated with 0.2 µg/ml anti-CD3 mAb, 30 µg/ml SEA, 0.5 µg/ml omega-1, or 10 µg/ml of soluble tachyzoite antigen (STAg). Cytokines were measured by ELISA in 72-h supernatants. Data shown are means ± SD of ELISA values for each pool. ICS was performed after supernatant removal. When restimulated with SEA, the frequency of IL-4⁺ CD4⁺ T cells in pooled LN cultures from mice that received SEA- or omega-primed DCs was 14 and 8.8%, respectively, and when the same cultures were restimulated with omega-1 the frequencies were 7.2 and 7.9%. One representative experiment out of three performed is shown. When omega-1–pretreated B cells were injected instead of DCs, no immune response was detected (not depicted).