Human neutrophil‐like cells demonstrate antimicrobial responses to the chronic cyst form of Toxoplasma gondii

Abstract

The protozoan parasite Toxoplasma gondii infects approximately 2.5 billion people worldwide. Infection induces a rapid dissemination of parasites throughout the body followed by the formation of lifelong cysts within neurons of the host brain. Both stages require a dynamic immune response comprised of both innate and adaptive cells. Neutrophils are a primary responding cell to acute infection and have been observed in the brain during murine chronic infection. Previous studies investigating human neutrophils found that invasion by Toxoplasma tachyzoites inhibits apoptosis of neutrophils, prolonging their survival under inflammatory conditions. Here, we demonstrate the differentiation of two distinct subsets following exposure of human neutrophil‐like‐cells (HNLC) to Toxoplasma cysts. In vitro stimulation and imaging studies show cyst‐specific induction of cytokines and cyst clearance by HNLCs. Further testing demonstrates that aged HNLCs perform less phagocytosis of cysts compared to non‐aged HNLCs. In conclusion, this study identifies a novel response of HNLCs to Toxoplasma cysts and may indicate a role for neutrophils in the clearance of cysts during human infection with Toxoplasma.

Contrasting Disease Progression, Microglia Reactivity, Tolerance, and Resistance to Toxoplasma gondii Infection in Two Mouse Strains

“…Transcriptomic analysis of C57BL/6 and BALB/c mice during progressive chronic T. gondii infection showed important changes in host genes [75]. It is of interest to note that during T. gondii infection, human neutrophil-like cells have been found to demonstrate antimicrobial responses to chronic cysts, suggesting their participation in clearing the parasite [87,88].…”