Regional specialization of intraepithelial T cells and microbiota in the pig intestinal tract

Authors: WIARDA, JAYNE - Iowa State University; Anderson, Christopher; WATKINS, HANNAH - Iowa State University; GABLER, NICHOLAS - Iowa State University; Loving, Crystal

Submitted to: Conference Research Workers Disease Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/20/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Objective Intraepithelial T lymphocytes (T-IELs) contribute to immune defense at the intestinal barrier and are in close association with microbes that modulate their functions. Understanding how T-IELs provide immune defense against enteric disease in pigs is limited, as little is known of cellular phenotypes comprising T-IEL populations in the porcine intestine. However, identification of different T-IEL phenotypes can be used to infer biological functions. Parallel analysis of both T-IEL and microbial diversity in porcine intestine has also not been completed but could inform on potential relationships between T-IELs and microbiota. Therefore, the objective of the study was to perform parallel assessment of community structures for T-IELs and microbiota across intestinal locations in pigs. Methods T-IELs and microbial swabs were collected from jejunum, ileum, and cecum of 5- and 7-week-old pigs. T-IEL phenotypes were assessed via flow cytometry. Microbial diversity was assessed via 16S sequencing. Results T-IELs with innate-like phenotypes were found in higher proportions in distal intestine, including discovery of CD8aa+ ab T-IELs (CD3e+gdTCR-CD4-CD8a+CD8b-) that comprised 2-15% of total T-IELs in cecum. While age-specific shifts to T-IEL communities occurred in jejunum and ileum, age-specific shifts to microbial communities occurred only in cecum. Conclusions Findings indicate different functions of T-IELs based on intestinal location, where distally-located T-IELs have phenotypes associated with innate-like functions. Though we find T-IEL and microbial communities stabilize at different rates in different regions of the intestinal tract, further work is still required to determine if causational interactions exist between intestinal T-IELs and the microbiota in pigs. Nonetheless, results emphasize the intestinal tract is a regionally specialized tissue system in regards to both immune cells and microbiota. The context of our findings pertaining to intestinal regional specialization should be considered in disease research, as specific pathogens target different intestinal regions for invasion.