In primed T cells, dbcAMP did not downregulate IL-2R expression, but did suppress JAK3 expression. (A) Highly purified T cells were activated for 3 days with PHA and then cultured for an additional 48 hours in medium alone or medium supplemented with 1 mmol/L dbcAMP. Surface levels of IL-2R, IL-2Rβ, and the γ chain were then determined by staining cells as described in the legend to Fig 5. The percentage of cells in each quadrant is presented adjacent to the histogram. (B) Aliquots of the same cells were subjected to Western blotting to determine if dbcAMP suppressed JAK3. Representative data from one of four experiments are presented.