In vitro stimulation with OVA-Exo induces a potent Th1 response in mice sensitized with OVA-Exo and challenged with OVA in vivo. OVA + OVA-Exo, OVA + Alum, or OVA alone primed mice groups were boosted with OVA, and 2 weeks later splenocytes were restimulated for 48 hours. (A) Proliferation was detected by thymidine incorporation assay, and the production of (B) IL-2, (C) TNF-α, and (D) IFN-γ was measured by cytometric bead array from the culture supernatant. Results are expressed as picograms per milliliter. Recombinant cytokines were used for standard curves for the quantification of sample cytokines by software provided by BD Biosciences. Data are presented as mean of 7 mice per group plus or minus SEM.