Figure 5. In vitro induction of cytokine secretion from human PBMCs by HAC1. Human PBMCs isolated 21 d post vaccination were stimulated in vitro with HAC1 or the vaccine antigen or left non-stimulated (Neg) for 3 d and the level of 10 different cytokines was measured in the cell supernatant by multiplex cytokine assay. Each symbol represents one individual volunteer. Bars represent the mean ± standard error of the mean (SEM). * and ** indicate significant difference with p < 0.05 and p < 0.005, respectively. n = 19.