Mucosal Associated Invariant T (MAIT) Cells are Highly Activated in Duodenal Tissue of Humans with Vibrio cholerae Infection

Cholera is a diarrheal disease caused by infection by V. cholerae O1/O139. The mechanisms of protection against cholera are poorly understood, particularly with regard to immune responses in the intestinal mucosa. We have previously shown that circulating MAIT cells are activated during cholera and associated with V. cholerae LPS-specific antibody responses. In this study, we enrolled 6 adults with confirmed V. cholerae O1 infection, and obtained blood, stool, and duodenal biopsy specimens by endoscopic procedure, on days 2 and 30 after onset of disease. We found that the frequency (~2%) of MAIT cells as % of CD3⁺ cells are similar in the periphery and the lamina propria (LP) and do not change between acute and convalescent phases. We found that a greater percentage of MAIT cells are activated (CD38⁺) in the LP at day 2 compared to day 30. At all time points, MAIT cell activation was higher in the LP than in the periphery. Stool alpha-1-antitrypsin, a marker of intestinal permeability, was correlated with decrease in % of activated MAITs between days 2 and 30. Enrollment for this study is ongoing, as well as analysis of corresponding antibody responses, and updated results will be available for presentation and discussion.