Development of lntraepithelial Cells in the Porcine Small Intestine

Journal of Immunology Research, Aug 2018

The number, phenotype, localisation and development of intraepithelial lymphocytes (IEL) from duodenum (Du) and ileum (Il) were studied by immunohistochemistry (IHC) and light and electron microscopy in unweaned (0–7 weeks old) and six months-old pigs. Developmental changes at birth showed that 38% of the total lymphocytes in the villi were IEL, mainly of the CD2

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

http://downloads.hindawi.com/journals/jir/2001/025301.pdf

Development of lntraepithelial Cells in the Porcine Small Intestine

Developmental Immunology Development of lntraepithelial Cells in the Porcine Small Intestine M.A. VEGA-L( 0 G. ARENAS-CONTRERAS 0 M. BAILEY 0 S. GONZALEZ-POZOS 0 C.R. STOKES 0 M.G. ORTEGA 0 R. MONDRAG( 0 N-FLORES 0 0 aCenterfor Research and Advanced Studies (CINVESTAV-IPN), Dept. Experimental Pathology The number, phenotype, localisation and development of intraepithelial lymphocytes (IEL) from duodenum (Du) and ileum (I1) were studied by immunohistochemistry (IHC) and light and electron microscopy in unweaned (0-7 weeks old) and six months-old pigs. Developmental changes at birth showed that 38% of the total lymphocytes in the villi were IEL, mainly of the CD2+CD4-CD8- double negative (DN) phenotype. That proportion rose to over 50% at week 5 after birth, resembling adult proportion, although still with fewer cells than in adult pigs. CD4+ cells appeared relatively early in life although they were confined to the lamina propria (LP) and CD8+ cells were found only in low numbers. In the villi of adult animals, almost'half of the total number of lymphocytes were IEL (49% Du, 52% I1). Over half of these IEL (52% Du, 53% I1) showed the CD2+CD4-CD8+ phenotype and were localized at the epithelium's basement membrane. Numerous (43% Du, 42% I1) DN IEL were found grouped at the enterocyte nucleus level and relatively few (5% in Du and I1) granular IEL were found apically in the epithelium. These proportions were homogeneously maintained along the villi's tip, middle and bottom, suggesting that the IEL may have their origin in the LP. Therefore, the IEL compartment in the porcine intestine develops slowly with age and is actually composed by a heterogeneous population of cells (null, DN and CD8+). These results may explain the increased susceptibility of young animals to disease during the lactation period and should be taken into account when functional studies are carried out with IEL. The quantitative results of this paper established a model for studies on the effect of age, diet, normal flora, infection and oral immunization on the IEL of the gut. IEL; immune development; lymphocyte; mucosal immunology; small intestine; swine INTRODUCTION Oral immunization has aroused great interest and expectation since this route may represent an alternative for disease control and also to prevent and control autoimmune diseases by inducing tolerance to autologous antigens (Brandtzaeg, 1995) . The mucosal immune system has some similarities but also many differences with the systemic immune system (Stokes, 1988; Kiyono, et al., 1992) . On the one hand, both systems contain cells which follow similar developmental pattems and effector functions (McGhee and Kiyono, 1993). On the other, differences in cell distribution and immune regulation have also been described (Kiyono, et al., 1992) . Unlike the systemic immunological tissues, the mucosal immune system in the gut must continuously deal with an enormous array of foreign material and must be able to accurately discriminate between harmless food antigens and commensal microorganisms and hazardous material, inducing anergy and/or tolerance to the former and a strong local and systemic immune response against the latter (Bienenstock, et al., 1987; Moqbel and MacDonald, 1990; Stokes, et al., 1994) . Moreover, the local immune system must maintains an appropriate balance between the organism and bacteria from the normal flora of the gut by mechanisms such as IgA-mediated immune exclusion (Stokes et al. 1975; Walker, 1987; Husby, 1988; Brandtzaeg, 1995) . These two functions of the local immune system are likely to be carried out through regulatory mechanisms different to those found in the systemic immune system and, perhaps, through subtle but substantial differences in the type and function of the cells found at the mucosal sites. The gut contains the largest number of immune cells in the organism, approximately 60% of all lymphocytes (Parrot, 1987; Hamad and Klein, 1994; Takahashi and Kiyono, 1999) . Many T cells are located in the lamina propria (LPL) and within the epithelium (intraepithelial lymphocytes, IEL) (Moqbel and MacDonald, 1990) . Because of their vicinity to the intestinal lumen and their access to food antigens, IEL are strategically located to induce, regulate and perform immune responses (Pabst, 1987; Cerf-Bensussan and Guy-Grand, 1991; McGhee, et al., 1992) . Previous studies in the pig have demonstrated that, unlike rodents and humans, the lymphoid components of the intestinal villi are poorly developed at birth (Vega-Lopez, et al., 1993; Pabst and Rothkotter, 1999) . The postnatal development of this compartment appears to be driven by exposure to microbial antigens, since it does not occur in germ-free pigs (Pabst and Rothkotter, 1999) and is accelerated by weaning in conventional pigs (Vega-Lopez, et al., 1995) . The pig therefore provides an appropriate system to study the development of IEL compartments in response to antigen. (...truncated)


This is a preview of a remote PDF: http://downloads.hindawi.com/journals/jir/2001/025301.pdf

M. A. Vega-López, G. Arenas-Contreras, M. Bailey, S. González-Pozos, C. R. Stokes, M. G. Ortega, R. Mondragón-Flores. Development of lntraepithelial Cells in the Porcine Small Intestine, Journal of Immunology Research, 8, DOI: 10.1155/2001/25301