Fig. 1.

L. panamensis infection induces TNF-α production at comparable levels and kinetics to those with specific TLR ligands. (A) Kinetics of TNF-α production in human primary macrophages exposed to different parasite-to-cell ratios, with maximum cytokine secretion at 8 h postinfection. Data are representative of cytokine production by macrophages of 10 individuals and are expressed as means ± standard errors of the means (SEM). (B) Production of TNF-α in human primary macrophages from 10 different donors was measured by ELISA. Cells were stimulated with zymosan, LPS, or poly(I:C), infected for 8 h with promastigotes at a 5:1 parasite-to-macrophage ratio, or left untreated as a control. Data are expressed as means ± standard deviations (SD). *, P < 0.05; **, P < 0.01.