Ontogeny of Pig Discrete Peyer's Patches: Expression of Surface Antigens.

Abstract

ABSTRACT. Leukocyte populations present in the discrete Peyer's patches (PP) of the pig were characterized from birth (Day 0) to day 35 after birth by immunohistochemistry and image analysis. Immediately after birth, cell membrane expression of CD2 and CD3, major histocompatibilty complex (MHC) class II (both SLA (swine leukocyte antigen) -DQ + and SLA-DR + ), CD21, 74-22-15 and surface immunoglobulin (sIg) were all demonstrable. Computer assisted morphometric techniques were used to confirm the significant expansion of these cell populations from birth onwards. The distribution of the cell types was not random but suggested a preferential retention of cells at specific sites. This implies a degree of organization of immunological cells within the discrete PP, enhancing the potential to mount immune responses in the most efficient manner. KEY WORDS: discrete Peyer's patch, ontogeny, surface antigen expression, swine.J. Vet. Med. Sci. 63(6): 625-636, 2001 The development of peripheral lymphoid organs has been investigated morphologically by many authors [6, 8,26,29,30]. Most of these studies dealt with the lymphoid cells: B cells, T cells and plasma cells [2,10]. Other reports have been focused on the ontogeny of the non-lymphoid cells in peripheral lymphoid organs: macrophages, interdigitating cells, follicular dendritic cells, and reticulum cells [9,29,30]. Internally, lymphoid organs comprise several compartments [7], each with their own function [13] and characteristic cell population [31]. Within the Peyer's patches (PP), the cooperation between diverse types of lymphoid and nonlymphoid cells is essential for optimal immune response. The aim of this work was to provide information regarding interactions of lymphoid and non-lymphoid cells and to investigate the development of these cells in the pig discrete PP, the major organized lymphoid structures involved in the induction of mucosal immune responses in the intestine. MATERIALS AND METHODSAnimals: Samples were taken from newborn Large White/ Landrace hybrid piglets. All piglets were maintained in conventional conditions on a commercial diet (Willets, Bristol, UK). They ranged from 0-35 days of age and both sexes were used. Piglets were sacrificed at 0 (presuckled), 1, 2, 4, 6, 8, 10, 12, 14, 18, 21, 28 and 35 days after birth. From day 0 to day 12, 3 piglets, 1 from each litter, were used, and from day 14 to day 35, 1 piglet from 1 litter was used. The piglets during this period (day 0-day 35) were not weaned. Tissue collection and preparation: Tissue blocks approximately 5-15 mm × 10 mm, were excised and snap frozen in OCT cryoprotection medium (Tissue-Tek, London, UK) using liquid nitrogen-cooled isopentane. Tissues were labeled for identification by writing on the back of the corkmounting disk. The tissues were wrapped in aluminium foil and polybags to prevent dehydration and stored at -70°C until further processing.Peroxidase anti-peroxidase staining: Serial 4-6 µm frozen sections were cut onto multi-spot, poly-l-lysine precoated slides, dried for 1...

BOARD-INVITED REVIEW: Porcine mucosal immunity of the gastrointestinal tract1

“…Subsequent to immune induction, the lamina propria has proven to function as the regulator of immune responses in the intestine (Makala et al, 2001). The gastrointestinal lamina propria is composed of smooth muscle cells, fibroblasts, blood vessels, and lymphatics that make up a highly vascular layer of loose connective tissue underlying and supporting the mucosal epithelium (Hunyady et al, 2000).…”

Antigen presenting cells in mucosal sites of veterinary species

“…Again, it was apparent that several subsets of APC were present, identified by different intensity of immunohistochemical labelling with the porcine myeloid marker SwC3, now known to be the porcine homologue to CD172a (SIRPα) [69]. In a second study, cells were also isolated from pig PP based on their low buoyant density [68].…”

Phenotype and Function of Murine Discrete Peyer's Patch Macrophage Derived-Dendritic Cells

“…In parallel studies [22][23][24][25][26] have shown that Mø can differentiate into functional DC. Exposure to macrophage colony-stimulating factor (M-CSF) induces only macrophage formation, whereas granulocyte-macrophage colony-stimulating factor (GM-CSF) also induces DC formation [28,49].…”

“…Peyer's Patches (PP) are the major organized lymphoid structures involved in the induction of mucosal immune responses in the intestine [22][23][24]. Joseph Conrad Peyer in 1677 provided the first accurate description of these discrete lymphoid aggregates in the intestinal wall, which have come to bear his name [14,35].…”

“…Although the initial transformation into a DC form is reversible, exposure to pro-inflammatory cytokines such as tumor necrosis factor-α (TNFα) induces an apparently irreversible maturation to DC [28,49]. GM-CSF, TNFα, and interleukin-4 are widely used to induce DC development from blood monocytes, and this is currently the favoured procedure for generating DC for immunotherapy [19,[22][23][24][25][26]49]. Since DC constitute about 1% of the total body cell population, they are very difficult to isolate.…”