Monocyte chemotactic protein-1 secretion and expression after Toxoplasma gondii infection in vitro depend on the stage of the parasite.

Infection of human fibroblasts with tachyzoites of RH and Prugniaud strains, two different strains of Toxoplasma gondii, significantly increased monocyte chemotactic protein (MCP)-1 secretion contrary to what happened with bradyzoites of the cystogenetic strain. Quantification of MCP-1 mRNA by RT-PCR showed that this phenomenon is regulated at the transcriptional level. Thus, the stage of parasite can be deciding in MCP-1 induction since only tachyzoites induced MCP-1 expression and secretion. MCP-1 induced by tachyzoites could be involved in cell recruitment, as shown by the quantification of MCP1 ARNm by real-time PCR (LightCycler, Roche Diagnostics), in the pathogenesis of T. gondii infection.