Figure 2. Effect of CdCl₂ or PbCl₂ on cytokine release by bacteria-stimulated human Peripheral blood mononuclear cells (PBMCs).

Supernatant levels of IL-10 (A) and IL-12 (B) released by bacteria-stimulated and control human PBMCs in the presence and absence of CdCl₂ (20 and 68 μM) or PbCl₂ (100 μM) for 24 hours. A set of bacteria Data are expressed as the mean ± SEM pg.mL⁻¹, n = 4 donors; *p < 0.05, **p < 0.01. Metals were simultaneously added to PBMCs with respectively five bacterial strains, a set of microorganisms known for their immune stimulatory properties at various ranges of cytokine levels (Lactobacillus acidophilus NCFM, Lactococcus lactis MG1363, Escherichia coli TG1, Lactobacillus salivarius LS33 and Bifidobacterium longum BB536)⁵⁵. While heavy metal salts do not induce any pro- or anti-inflammatory cytokines at baseline, they can dose-dependently affect immune responses and cytokine levels when other external stimuli occur simultaneously.