Induction of gut-homing receptors in T cells in response to retinoic acid requires the transcription factor BATF.

Airborne pathogens commonly trigger severe respiratory failure or death in smokers with lung disease. Cigarette smoking compromises the effectiveness of innate immunity against infections but the underlying mechanisms responsible for defective acquired immune responses in smokers remains less clear. We found that mice exposed to chronic cigarette smoke recovered poorly from primary Influenza A pneumonia with reduced type I and II interferons (IFNs) and viral-specific immunoglobulins, but recruited gamma delta (γδ) T cells to the lungs that predominantly expressed interleukin 17A (IL-17A). Il-17a-/- mice exposed to smoke and infected with Influenza A also recruited γδ T cells to the lungs, but in contrast to wild type mice, expressed increased IFNs, made protective influenza specific antibodies, and recovered from infection. Depletion of IL-17A with blocking antibodies significantly increased T-bet expression in γδ T cells and improved recovery from acute Influenza A infection in air, but not smoke exposed mice. In contrast, when exposed to smoke, γδ T cell deficient mice failed to mount an effective immune response to Influenza A and showed increased mortality. Our findings demonstrate a protective role for γδ T cells in smokers and suggest that smoke-induced increase in IL-17A inhibits the transcriptional programs required for their optimal anti-viral responses.

Microbiota plays a critical role in the overall growth performance and health status of dairy cows, especially during their early life. Several studies have reported that fecal microbiome of neonatal calves is shifted by various factors such as diarrhea, antibiotic treatment, or environmental changes. Despite the importance of gut microbiome, a lack of knowledge regarding the composition and functions of microbiota impedes the development of new strategies for improving growth performance and disease resistance during the neonatal calf period. In this study, we utilized next-generation sequencing to monitor the time-dependent dynamics of the gut microbiota of dairy calves before weaning (1–8 weeks of age) and further investigated the microbiome changes caused by diarrhea. Metagenomic analysis revealed that continuous changes, including increasing gut microbiome diversity, occurred from 1 to 5 weeks of age. However, the composition and diversity of the fecal microbiome did not change after 6 weeks of age. The most prominent changes in the fecal microbiome composition caused by aging at family level were a decreased abundance of Bacteroidaceae and Enterobacteriaceae and an increased abundance of Prevotellaceae. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis indicated that the abundance of microbial genes associated with various metabolic pathways changed with aging. All calves with diarrhea symptoms showed drastic microbiome changes and about a week later returned to the microbiome of pre-diarrheal stage regardless of age. At phylum level, abundance of Bacteroidetes was decreased (p = 0.09) and that of Proteobacteria increased (p = 0.07) during diarrhea. PICRUSt analysis indicated that microbial metabolism-related genes, such as starch and sucrose metabolism, sphingolipid metabolism, alanine aspartate, and glutamate metabolism were significantly altered in diarrheal calves. Together, these results highlight the important implications of gut microbiota in gut metabolism and health status of neonatal dairy calves.

The microbial community within the rumen can be changed and shaped by heat stress. Accumulating data have suggested that different breeds of dairy cows have differential heat stress resistance; however, the underlying mechanism by which nonanimal factors contribute to heat stress are yet to be understood. This study is designed to determine changes in the rumen microbiome of Holstein and Jersey cows to normal and heat stress conditions. Under heat stress conditions, Holstein cows had a significantly higher respiration rate than Jersey cows. Heat stress increased the rectal temperature of Holstein but not Jersey cows. In the Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, Jersey cows had a significantly higher proportion of genes associated with energy metabolism in the normal condition than that with other treatments. Linear discriminant analysis effect size (LEfSe) results identified six taxa as distinguishing taxa between normal and heat stress conditions in Holstein cows; in Jersey cows, 29 such taxa were identified. Changes in the rumen bacterial taxa were more sensitive to heat stress in Jersey cows than in Holstein cows, suggesting that the rumen mechanism is different in both breeds in adapting to heat stress. Collectively, distinct changes in rumen bacterial taxa and functional gene abundance in Jersey cows may be associated with better adaptation ability to heat stress.