Abstract
Toxoplasma gondii is an intracellular protozoan parasite. The parasite is capable of penetrating to human monocytes. Some studies showed immune responses to Toxoplasma gondii infection. However, acute cytokine responses of monocytes from sero negative individuls to the parasite are still elusive. Therefore, we studied cytokine responses of enriched human monocytes to tachyzoites in culture medium as an in vitro model of acute Toxoplasma gondii infection. Human monocytes were stimulated by tachyzoites in culture medium. Cytokine productions were determined by ELISA. Viability of cells was determined to find whether the monocytes were alive and functioning following the parasite infection. Infected monocyte viability was more than 98% after 18 hours indicating that they were functional cytokine secreting cells. Infection by the parasite increased proinflammatory cytokines such as IL-6 and TNFa significantly. Similarly IL-17 production increased after the infection. Anti-inflammatory cytokines such as IL-10 and TGFb productions were altered significantly as well. These results indicated that cytokines released by infected monocytes might contribute regulatory mechanisms of T cell activations during acute infections of Toxoplasma gondii.
