Toxoplasma gondii eIF-5A Modulates the Immune Response of Murine Macrophages In Vitro.

Toxoplasma gondii ( T. gondii ) is an obligate intracellular protozoan that can elicit a robust immune response during infection. Macrophage cells have been shown to play an important role in the immune response against T. gondii . In our previous study, the eukaryotic translation initiation factor 5A (eIF-5A) gene of T. gondii was found to influence the invasion and replication of tachyzoites. In this study, the recombinant protein of T. gondii eIF-5A (r Tg eIF-5A) was incubated with murine macrophages, and the regulatory effect of Tg eIF-5A on macrophages was characterized. Immunofluorescence assay showed that Tg eIF-5A was able to bind to macrophages and partially be internalized. The Toll-like receptor 4 (TLR4) level and chemotaxis of macrophages stimulated with Tg eIF-5A were reduced. However, the phagocytosis and apoptosis of macrophages were amplified by Tg eIF-5A. Meanwhile, the cell viability experiment indicated that Tg eIF-5A can promote the viability of macrophages, and in the secretion assays, Tg eIF-5A can induce the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and nitric oxide (NO) from macrophages. These findings demonstrate that eIF-5A of T. gondii can modulate the immune response of murine macrophages in vitro, which may provide a reference for further research on developing T. gondii vaccines.