Suppression of OT-II CD4⁺ T cell expansion by TLR agonists is IL-2 independent.

<p>OT-II CD4⁺ T cells/DC co-cultures were stimulated with OVA protein (25 μg/ml) in the presence or absence CL097 (1 μg/ml) for 5 days. (A) Various concentrations of recombinant IL-2 or (B) neutralizing anti-IL-2 antibody were added to the cultures during stimulation. The two sets of ranges and numbers in each histogram represent cells that proliferated more than three times (upper) and at least one time (lower). (C) The cultures were stimulated with OVA protein in the presence or absence of CpG or CL097 for three days, and the cells were stained for CD25 and FoxP3 to measure expression levels of CD25 on FoxP3^- and FoxP3⁺ CD4⁺ T cells. Data shown are representative of three independent experiments.