HOST-PATHOGEN INTERACTIONS BETWEEN BLASTOCYSTIS SPP. AND THE HUMAN HOST-IN VITRO STUDIES INTO EFFECTS ON HOST IMMUNITY

Abstract

BLASTOCYSTIS SPP. IS AN ENTERIC STRAMENOPILE PARASITE ASSOCIATED WITH GASTROINTESTINAL SYMPTOMS. BLASTOCYSTIS HAS BEEN FOUND TO INCREASE EPITHELIAL PERMEABILITY AND DISRUPT PERICELLULAR TIGHT JUNCTIONS, LEADING TO BARRIER FUNCTION COMPROMISE. WE COMPARED EFFECTS OF 2 CLINICALLY RELEVANT BLASTOCYSTIS SUBTYPES, 4 AND 7, ON EPITHELIAL PERMEABILITY USING EXPOSURE RATIOS CORRECTED FOR DIFFERENCES IN CELL SIZE AND PROTEIN CONTENT. OUR FINDINGS MIRRORED PREVIOUS OBSERVATIONS, THAT ST7-B WAS MORE POTENT IN INDUCING EPITHELIAL PERMEABILITY INCREASE. WE USED THESE ADJUSTED RATIOS TO INVESTIGATE BLASTOCYSTIS EFFECTS ON TLR ACTIVATION AND DENDRITIC CELL ACTIVATION AND MATURATION. WE FOUND THAT WHILE PARASITE EXPOSURE ALONE DID NOT ACTIVATE TLRS, BLASTOCYSTIS MODULATED TLR ACTIVATION BY SPECIFIC LIGANDS. WE ALSO OBSERVED THAT ST7-B AND NOT ST4-WR1 ACTIVATED AND MATURED HUMAN MONOCYTE-DERIVED DENDRITIC CELLS AFTER PHAGOCYTIC UPTAKE AND INDUCED TNF-A PRODUCTION. THESE FINDINGS, TAKEN TOGETHER, SUGGES