FIG. 7.

PvTRAg40- and PHA-induced Th1-type cytokine responses in P. vivax-exposed human subjects and malaria-naïve individuals. Individual supernatants from quadruplicate cultures of each sample were collected after 48 h of cell stimulation, pooled, diluted 1:1 with culture medium, and assayed by sandwich ELISA. Cytokine secretion in response to PHA and medium alone was also estimated and plotted. The graphs represent the secretion of IFN-γ (a), TNF-α (b), and IL-12 (c). Open circles represent cytokine values for control individuals who had no history of malaria exposure (n = 10), and solid circles represent values for subjects recently exposed to P. vivax who had recovered 8 to 14 weeks prior to study (n = 20). The geometric mean is shown by a horizontal line for each group.