Nuclear factor-kappa B plays a major role in the regulation of chemokine expression of HeLa cells in response to Toxoplasma gondii infection

Toxoplasma gondii infection results in an infiltration of immune cells. The mechanisms responsible for triggering inflammatory cell infiltration in T. gondii infection are not fully understood. We report that T. gondii-infect ed HeLa cells induced nuclear factor-kappa B (NF-kappaB) activation and inc reased the expression of interleukin-8 (IL-8) and monocyte chemotactic prot ein-1 (MCP-1) mRNA. An inhibitor of NF-kappaB activation, calpain-1 inhibit or, blocked the chemokine secretion induced by live T. gondii. Activation o f the IL-8 and NF-kappaB transcriptional reporters was suppressed in cells co-transfected with I kappaB kinase beta and the I kappaB alpha super-repre ssor plasmids. Moreover, the addition of IL-1 alpha increased NF-kappaB act ivation and IL-8 mRNA expression in T. gondii-infected HeLa cells. These re sults suggest that NF-kappaB is a central regulator of the chemokine respon se in T. gondii-infected human epithelial cells and that chemokine IL-8 and MCP-1 secretion might be involved in the pathogenesis of T. gondii, via th e recruitment of neutrophils, monocytes, and lymphocytes.