A high throughput analysis of cytokines and chemokines expression during the course of Trypanosoma cruzi experimental oral infection.

Trypanosoma cruzi has high biological and biochemical diversity and variable tissue tropism. Here we aimed to verify the kinetics of cytokine and chemokine in situ secretion in animals infected with two distinct T. cruzi strains after oral inoculation. Also, we investigated parasite migration, residence and pathological damage in stomach, heart and spleen. Our results showed that host immune response against T. cruzi infection is an intricate phenomenon that depends on the parasite strain, on the infected organ and on the time point of the infection. We believe that a wide comprehension of host immune response will potentially provide basis for the development of immunotherapeutic strategies in order to clear parasitism and minimize tissue injury. In this context, we find that KC poses as a possible tool to be used.

A recombinant protein based on Trypanosoma cruzi P21 enhances phagocytosis.

BACKGROUND: P21 is a secreted protein expressed in all developmental stages of Trypanosoma cruzi. The aim of this study was to determine the effect of the recombinant protein based on P21 (P21-His(6)) on inflammatory macrophages during phagocytosis. FINDINGS: Our results showed that P21-His(6) acts as a phagocytosis inducer by binding to CXCR4 chemokine receptor and activating actin polymerization in a way dependent onthe PI3-kinase signaling pathway. CONCLUSIONS: Thus, our results shed light on the notion that native P21 is a component related to T. cruzi evasion from the immune response and that CXCR4 may be involved in phagocytosis. P21-His(6) represents an important experimental control tool to study phagocytosis signaling pathways of different intracellular parasites and particles.

IFN-γ plays a unique role in protection against low virulent Trypanosoma cruzi strain.

BACKGROUND: T. cruzi strains have been divided into six discrete typing units (DTUs) according to their genetic background. These groups are designated T. cruzi I to VI. In this context, amastigotes from G strain (T. cruzi I) are highly infective in vitro and show no parasitemia in vivo. Here we aimed to understand why amastigotes from G strain are highly infective in vitro and do not contribute for a patent in vivo infection. METHODOLOGY/PRINCIPAL FINDINGS: Our in vitro studies demonstrated the first evidence that IFN-γ would be associated to the low virulence of G strain in vivo. After intraperitoneal amastigotes inoculation in wild-type and knockout mice for TNF-α, Nod2, Myd88, iNOS, IL-12p40, IL-18, CD4, CD8 and IFN-γ we found that the latter is crucial for controlling infection by G strain amastigotes. CONCLUSIONS/SIGNIFICANCE: Our results showed that amastigotes from G strain are highly infective in vitro but did not contribute for a patent infection in vivo due to its susceptibility to IFN-γ production by host immune cells. These data are useful to understand the mechanisms underlying the contrasting behavior of different T. cruzi groups for in vitro and in vivo infection.