Effects of Cytokines IFN-γ and TGF-β on the Functional Activity of Blood Mononuclear Cells against Giardia lamblia

Background: This study aimed to analyze cultures of mononuclear (MN) cells with Giardia lamblia to determine the levels of the cytokines IFN-γ and TGF-β and the functional activity of MN cells after incubation with cytokines. Methods: This study was conducted in 2018 in Barra do Garças, Mato Grosso State, Brazil. Blood samples were collected from 60 healthy volunteer donors to obtain leukocytes. The levels of IFN-γ and TGF-β were quantified in trophozoite cell culture supernatants. Superoxide release, phagocytosis, microbicidal activity, apoptosis and intracellular calcium release were analyzed. Results: The cytokines evaluated were detected in the culture supernatant of MN cells and G. lamblia. Regardless of the type of cytokine, MN cells increased superoxide release in the presence of G. lamblia. Phagocytosis, microbicidal activity and apoptosis were higher when MN phagocytes were treated with cytokines. The highest microbicidal activity and apoptosis rates were observed in MN cells cultured with TGF-β. IFN-γ increased the release of intracellular calcium by MN phagocytes. Conclusion: Cytokines play a beneficial role in the host by activating MN cells against G. lamblia. In addition, phagocytosis causes G. lamblia death and that the modulation of the functional activity of blood MN phagocytes by cytokines is an alternative mechanism for eliminating G. lamblia.