DCs matured in the presence of adenosine are impaired in their capacity to initiate Th1 responses in vitro.
Immature DCs were left untreated or stimulated with 10−4 M adenosine (A-B) or 10−5 M adenosine (C) or induced to undergo maturation with LPS in the absence or the presence of adenosine for 24 hours. DCs were then used to prime purified allogeneic CD4+CD45RA+ naive T lymphocytes. After 5 days, T cells were restimulated with PMA and ionomycin and then examined for intracellular IFN-γ and IL-4 by flow cytometry (A). Only viable cells were gated and analyzed. Numbers indicate the percentage of positive cells in each quadrant. In parallel, supernatants from T cells were evaluated for secreted IFN-γ (■) and IL-5 (▪) (B-C). Results are expressed as mean ng/mL ± SD of triplicate cultures. *P < .02 between cytokines secreted by T cells stimulated with DCs treated or not with adenosine. Experiments were repeated 3 times from different donors with similar results. Data are means ± SD (n = 3).
