Competition between commensal protists shapes gut mucosal immunity in mice

Area of Science:

• * Gut immunology and host-microbial interactions.
• * Mammalian mucosal immunity and protist ecology.

Background:

• * Intestinal protists modulate host immunity and gut microbial ecology.
• * The impact of protists like Entamoeba and Tritrichomonas on mammalian hosts is not well understood.
• * Tritrichomonas activates type 2 immunity via the tuft cell-IL-25-ILC2 circuit.

Purpose of the Study:

• * To investigate the individual and combined roles of Entamoeba muris and Tritrichomonas in shaping gut immunity in vivo.
• * To determine how these protists interact and influence host immune responses.
• * To explore sex-specific differences in intestinal immune responses to Tritrichomonas.

Main Methods:

• * In vivo studies using mice models.
• * Investigated immune responses to individual and co-infections with Entamoeba muris and Tritrichomonas.
• * Analyzed protist abundance and host immune cell activation.

Main Results:

• * Entamoeba muris did not elicit robust immune responses on its own.
• * Co-infection or introduction of Entamoeba muris reduced Tritrichomonas-induced type 2 immunity.
• * Entamoeba muris may limit Tritrichomonas abundance, correlating with diminished tuft cell activation and sex-specific immune responses.

Conclusions:

• * Entamoeba muris dampens Tritrichomonas-dependent type 2 immunity activation in the small intestine.
• * This interaction occurs without inducing overt inflammation, even with detectable protist loads.
• * Findings provide a framework for understanding protist interactions and their impact on mucosal immunity.