FIG. 2.

Induction of proinflammatory cytokine secretion in mature human macrophages challenged with gonococci. Supernatants were removed from the macrophage cultures challenged with the gonococcal variants, and cytokine release was quantified by specific immunoassays. Protein secretion was detected for TNF-α, IL-8, GRO-α, IL-6, MIP-1α, and RANTES following challenge with Opa⁻ Pil⁻ (▧), Opa⁻ α-Pil⁺ (▪ ), Opa_a⁺ Pil⁻ (░⃞), and Opa_b⁺ Pil⁻ (▨) gonococci. Cytokine production at 6 h was compared with levels in unchallenged cultures (□). Individual bars represent the geometric mean cytokine concentration plus standard error from six independent wells. One-way analysis of variance was used to compare mean values, with P < 0.05 considered significant.