OmpA-sal-treated DCs induces proliferation of allogenic T cells and enhanced Th1 resoponse in vitro. The DCs were incubated for 24 h in medium alone, in 200 ng/ml LPS, or in 400 ng/ml of OmpA-sal. The DC were washed and co-cultured with T cells. Cluster formation was assessed after 72 h. One representative experiment of three is also included in the figure, showing a representative field in a culture well photographed using an inverted phase contrast microscope and a mixed lymphocyte reaction was allowed to proceed for 3 days, T-cell proliferation was analyzed by flow cytometry and presented as a percentage of dividing cells (A). Cells were then examined for cytokine release after 48 h. IFN-γ and IL-4 were measured by ELISA in culture supernatants (B, C). Medium represents the chemically untreated control group. Similar results were obtained and expressed as the means (±SD) from four separate experiments. **p < 0.01 vs. untreated DCs.