Oral administration of a select mixture of Bacillus probiotics generates Tr1 cells in weaned F4ab/acR − pigs challenged with an F4 + ETEC/VTEC/EPEC strain

Abstract Although breeding of F4 receptor − negative (F4R−) pigs may prevent post-weaning diarrhea, the underlying immunity is poorly understood. Here, various doses of a Bacillus licheniformis and Bacillus subtilis mixture (BLS-mix) were orally administered to F4ab/acR− pigs for 1 week before F4 (K88) − positive ETEC/VTEC/EPEC challenge. Administration of BLS-mix increased the percentage of Foxp3−IL-10+ T cells but not of Foxp3+IL-10+ regulatory T (Treg) cells among peripheral blood CD4+ T cells. A low dose of BLS-mix feeding resulted in increased the expression of IL-6, TNF-α, IL-10, and the transcription factors Foxp3 and T-bet mRNAs in the jejunum. Administration of either a low or high dose BLS-mix also led to an increase in the percentage of CD4+Foxp3+ Treg cells among intraepithelial lymphocytes and CD4+IL-10+ T cells in the small intestinal Peyer’s patches and the lamina propria of F4ab/acR− pigs following F4+ ETEC/VTEC/EPEC challenge. The increased number of IL-10–producing CD4+ T cells was attributed to an increase in the proportion of Foxp3−IL-10+ Treg cells rather than Foxp3+IL-10+ Treg cells. Our data indicate that oral administration of BLS-mix to newly weaned F4ab/acR− pigs ameliorates enteritis in an F4+ ETEC/VTEC/EPEC model; however, induction of IL-10–producing Foxp3− Treg cells by BLS-mix administration cannot account for the protection of newly weaned F4ab/acR− pigs from F4+ ETEC/VTEC/EPEC infection, ...
Source: Veterinary Research - Category: Veterinary Research Source Type: research