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This Article Full Text (PDF) All Versions of this Article: jas.2008-1381v1 87/14_suppl/E92    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Moretó, M. Articles by Pérez-Bosque, A. Search for Related Content PubMed PubMed Citation Articles by Moretó, M. Articles by Pérez-Bosque, A.

Dietary plasma proteins, the intestinal immune system and the barrier functions of the intestinal mucosa

M. Moretó^* and A. Pérez-Bosque^*,

^* Grup de Fisiologia i Nutrició Experimental, Departament de Fisiologia, Facultat de Farmàcia, Institut de Recerca en Nutrició i Seguretat Alimentària, Universitat de Barcelona, Spain APC Europe, Granollers, Spain

mmoreto{at}ub.edu

Abstract

The intestinal mucosa contributes to homeostasis by preventing the entrance of biological and chemical agents across the epithelium that could alter the stability of the system. This protective function is especially important at the time of weaning, when animals are exposed to infectious agents and to numerous stresses such as the change of environment and diet. Diets supplemented with spray-dried plasma or plasma protein fractions have been shown to improve growth performance of farm animals and have been proposed as an alternative to antibiotics. In this review, we summarize our findings on the mechanism of action of dietary plasma proteins using a rat model of intestinal inflammation, based on the administration of Staphylococcus aureus enterotoxin B (SEB). Staphylococcal enterotoxin B activates the gut associated lymphoid tissue (GALT), increasing T-lymphocytes in Peyer’s patches and the number of activated T lymphocytes in mesenteric lymph nodes (organized GALT). In the lamina propria SEB increased cytotoxic T and natural killer cell populations of the diffuse GALT. Staphyloccocal enterotoxin B significantly increased pro-inflammatory cytokines in both Peyer’s patches and mucosa. Plasma protein supplements modulated the mucosal immune response in both organized and diffuse GALT, protecting GALT from possible excessive activation by the SEB challenge. These effects are accompanied by a reduction of pro-inflammatory cytokine production, supporting the view that changes in cytokine production mediate the effects of dietary plasma proteins during intestinal inflammation. The increase in mucosal permeability and intestinal secretion induced by SEB was associated with decreased expression of mucosal tight-junction and adherent-junction proteins. Both plasma and plasma protein fractions prevented the effects of SEB on intestinal permeability thus reducing the exposure of the host to microbial and food antigens across the interstitial space. These findings indicate that dietary plasma proteins modulate both functional and structural properties of the intestinal mucosa.

Key Words: gut-associated lymphoid tissue • immunoglobulins • intestinal inflammation • nutrient absorption • spray-dried plasma • Staphylococcus aureus enterotoxin B