Intestinal location- and age-specific variation of intraepithelial T lymphocytes and mucosal microbiota in pigs.

Intraepithelial T lymphocytes (T-IELs) are T cells located within the epithelium that provide a critical line of immune defense in the intestinal tract. In pigs, T-IEL abundances and phenotypes are used to infer putative T-IEL functions and vary by intestinal location and age, though investigations regarding porcine T-IELs are relatively limited. In this study, we expand on analyses of porcine intestinal T-IELs to include additional phenotypic designations not previously recognized in pigs. We describe non-conventional CD8α+CD8ß- αß T-IELs that were most prevalent in the distal intestinal tract and primarily CD16+CD27-, a phenotype suggestive of innate-like activation and an activated cell state. Additional T-IEL populations included CD8α+CD8ß+ αß, CD2+CD8α+ γδ, and CD2+CD8α- γδ T-IELs, with increasing proportions of CD16+CD27- phenotype in the distal intestine. Thus, putative non-conventional, activated T-IELs were most abundant in the distal intestine within multiple γδ and αß T-IEL populations. A comparison of T-IEL and respective mucosal microbial community structures across jejunum, ileum, and cecum of 5- and 7-week-old pigs revealed largest community differences were tissue-dependent for both T-IELs and the microbiota. Between 5 and 7 weeks of age, the largest shifts in microbial community compositions occurred in the large intestine, while the largest shifts in T-IEL communities were in the small intestine. Therefore, results indicate different rates of community maturation and stabilization for porcine T-IELs and the mucosal microbiota for proximal versus distal intestinal locations between 5 and 7 weeks of age. Collectively, data emphasize the intestinal tract as a site of location- and age-specific T-IEL and microbial communities that have important implications for understanding intestinal health in pigs.

Ixodes scapularis: Vector to an Increasing Diversity of Human Pathogens in the Upper Midwest.

INTRODUCTION: The black-legged tick, Ixodes scapularis (I scapularis), is now recognized as the deadliest tick vector in the United States. The Upper Midwest, particularly Wisconsin and Minnesota, are endemic to a diversity of tick-transmitted infectious diseases. Although Borrelia burgdorferi, the agent of Lyme disease, still accounts for the majority of diagnosed infections, I scapularis is known to transmit other bacterial, viral, and parasitic agents. OBJECTIVE: To provide an overview of the array of pathogenic microorganisms carried by I scapularis ticks in the Upper Midwest. METHODS: A literature review was conducted to collect and analyze current information about I scapularis lifestyle, transmission, microorganisms carried by the arthropod vector, and the diseases that occur as a result of infections with these microorganisms in the Upper Midwest. RESULTS: Diagnosis of co-infection from tick-borne zoonosis in humans has increased over the last 2 decades. Since I scapularis can transmit multiple pathogens, it is clinically important because different diagnostic testing and treatment strategies may need to be implemented for a patient with I scapularis-borne infection(s). CONCLUSIONS: This review has concentrated on I scapularis-transmitted diseases affecting the Upper Midwest and has explored the ecology of the I scapularis vector and its role in pathogen transmission.