Conserved B cell signaling, activation, and differentiation in porcine jejunal and ileal Peyer's patches despite distinct immune landscapes

Abstract

Peyers patches (PPs) are B cell-rich sites of immune induction in the intestine, yet B cell signaling, activation, and differentiation associated with PPs are poorly defined. Single-cell and spatial transcriptomics were completed to study B cells from porcine jejunum and ileum containing PPs. Intestinal locations had distinct immune landscapes, including more follicular B cells in ileum and increased MHC-II-encoding gene expression in jejunal, non-resting B cells. Despite distinct landscapes, conserved B cell dynamics were detected across intestinal locations. B cell signaling to CD4+ macrophages that are putative phagocytic, cytotoxic, effector cells and deduced routes of B cell activation/differentiation, including resting B cells migrating into follicles to replicate/divide or differentiate into antibody-secreting cells residing in intestinal crypts, were conserved across locations. A six-biomarker panel recapitulated transcriptomics results of B cell phenotypes, frequencies, and spatial locations via ex vivo/in situ staining of gene/protein targets. Findings convey conserved B cell signaling, activation, and differentiation, despite location-specific immune environments in jejunum and ileum containing PPs. Results establish a benchmark of B cell dynamics for understanding intestinal immune induction important to promoting gut and overall health.