A Review about The Relationship Between Toxoplasmosis and Some Immunological Indicators

Background: Toxoplasma gondii is an intracellular pathogen that elicits evolution of compound immune responses involving the innate and adaptive immune systems. Toll-like receptors (TLRs) stimulate innate cells (dendritic cells and macrophages) at the early stages in the infection cascade, resulting in the production of IL-12, which is required for IFN-gamma production by T cells and natural killer (NK) cells for the control of the parasites. Interleukin-6 (IL-6) is also secreted during the early stages of the infection process; its overexpression is linked to tissue destruction. While an anti-inflammatory cytokine (IL-10) produced by regulatory T cells (Tregs) and some macrophages suppresses excessive immune response and enables the parasite to evade immune responses during chronic infection, IL-17 induces an inflammatory response and upregulation of this cytokine during acute infection is associated with tissue inflammation. TNF- a is one of the most remarkable necrosis factors found in the infection condition. Although it contributes to enhancement of the immune cell response, it is responsible for an increase in chronic inflammation, which explains why the parasite is able to evade more complex immunodefense mechanisms through the first line of defense against of T. gondii.