FIG 2.

Cytokine secretion by antigen-stimulated PBMCs, measured 1 month following aP booster. Cytokine (IFN-γ, IL-2, IL-10, and IL-4) production in response to pertussis antigens (PT, FHA, PRN, and FIM) and under unstimulated conditions (unstim) was compared by using the Wilcoxon signed-rank test. Cytokine levels are plotted as box-and-whisker plots. The bottom and top of the box represent the first and third quartiles, respectively, and the horizontal band inside the box represents the median. The ends of the whiskers represent the minimum and maximum values, excluding outliers. A two-tailed P value of ≤0.05 was considered to represent a significant increase in cytokine production in response to the tested antigen.