The sheep and cattle Peyer’s patch as a site of B-cell development

Abstract

-In sheep and cattle, the ileal Peyer's patch (PP), which extends one-two meters along the terminal small intestine, is a primary lymphoid organ of B-cell development. B-cell diversity in the ileal PP is thought to develop by combinatorial mechanisms, gene conversion and/or point mutation. These species also have jejunal PP that function more like secondary lymphoid tissues concerned with mucosal immune reactions. These two types of PP differ significantly in their histology, ontogeny and the extent of lymphocyte traffic. The prenatal development of follicles in the PP begins first in the jejunum during the middle of gestation and then in the ileum during late gestation. B-cells proliferate rapidly in the ileal PP follicle; up to five percent of these cells survive while the majority dies by apoptosis, perhaps driven by the influence of environmental antigen and/ or self-antigen. The surviving cells migrate from the ileal PP and populate the peripheral B-cell compartment. By adolescence, the ileal PP has involuted but the function of jejunal PP, compatible with a role as secondary lymphoid organ, continues throughout life. In this review, we focus on the development of PP as a site of B-cell repertoire generation, positive and negative B-cell selection, and the differences between ileal PP and jejunal PP.

Development of the neonatal B and T cell repertoire in swine: implications for comparative and veterinary immunology

“…Similar-appearing follicles in the chicken hindgut are known as the bursa of Fabricius and have been shown to be the site of B cell repertoire diversification [78,90]. Those in sheep appear to play a similar role [91,92,128]. Evidence for a similar role of the porcine IPP remains circumstantial.…”

Is peritoneal reflection the best anatomical repair landmark in experimental colorectal surgery on rats?

“…PP is found in sheep, calves, swine and horses in the ileum, while in the appendix in rabbits, and bursa in chickens 15 . Recent studies have indicated an interest in PP as an immune response mediator 15,16,17 , without giving importance to the distinct characteristics of the colonic tissue in evaluating the healing processes that take place on this structure. In the indexed literature, one single study makes mention of the collagen in this region 18 .…”

Secondary Lymphoid Areas in Calf Ileal Peyer's Patch

“…Ruminant's gut lymphoid tissue can be broadly classified into primary and secondary lymphoid tissues according to their architecture and life history [3,8,10]. Ileal Peyer's patch (PP) is thought to be the primary lymphoid organ of B-cell, whose repertoire is diversified by gene conversion and/or somatic hypermutation [7,13].…”

“…Histologically, densely packed lymphatic follicles are associated with small interfollicular T-cell areas [9]. Jejunal PP is thought to be the secondary lymphoid tissue for local mucosal immunity, and the functions of this lymphoid tissue is kept throughout animal's life [3,10,11]. Moreover, jejunal PP lymphatic follicles are widely dispersed and separated by large interfollicular T-cell areas [3,[9][10][11].…”

“…Jejunal PP is thought to be the secondary lymphoid tissue for local mucosal immunity, and the functions of this lymphoid tissue is kept throughout animal's life [3,10,11]. Moreover, jejunal PP lymphatic follicles are widely dispersed and separated by large interfollicular T-cell areas [3,[9][10][11]. At about 12 weeks old, sheep ileal PP begins to involute, and only a few lymphatic follicles remain in this area at 18 months old [8].…”