Effects of local budesonide treatment on the cell-mediated immune response in acute and relapsing colitis in rats.

Glucocorticosteroids (GCS) are effective in treatment of inflammatory bowel disease (IBD), but also have unwanted systemic side effects. Here, we describe the effects of budesonide and dexamethasone on acute experimental colitis and on T cells in thymus and spleen, as well as the effect of budesonide treatment on relapsing colitis. Acute colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) in ethanol, and a relapse was induced by an intraperitoneal booster of TNBS. GCS were administered intrarectally on days 1, 4, and 6 after induction of acute colitis or a relapse. Inflammatory cells in the colon were studied on day 7, and in acute colitis also on days 13 and 16. Budesonide treatment in acute and relapsing colitis resulted in reduction of macroscopic damage and decreased the numbers of macrophages and neutrophils in the colon. Dexamethasone was less effective. Dexamethasone, but not budesonide, reduced the number of T cells in the thymus. It is concluded that local budesonide is more effective in treatment of acute experimental colitis than dexamethasone and, in contrast to dexamethasone, did not cause a general suppression of T cells. Although budesonide was very effective in the treatment of relapsing colitis, this effect was not accomplished by affecting the number of T cells in the colon.

The in vivo antibody response in rat gut-associated lymphoid tissue (GALT) after immunization with bacterial polysaccharide antigen.

Gut mucosal immune responses to bacterial polysaccharide antigen in rats were investigated in vivo. Rats were immunized with pneumococcal polysaccharide type 3 (PPS-3) via different routes, i.e. in the Peyer's patch (iPP), in the colon (ic), in the peritoneal cavity (ip), and intravenously (iv). The development of specific antibody-forming cells (AFC) and their isotypes in the intestinal mucosa, gut-associated lymphoid tissue (GALT), mesenteric lymph nodes (MLN) and spleen were studied by immunohistochemistry. Furthermore, the serum antibody levels were measured by enzyme-linked immunosorbent assay (ELISA). The results showed that iPP immunization evoked high numbers of anti-PPS-3 AFC of the IgA isotype in the mucosa of the small intestine and in the PP. On the contrary, the ic route did not elicit a mucosal response, though a few AFC were found in the MLN and spleen. Following ip priming, a specific IgA response was found, especially in MLN and spleen, and a low response was detected in the villi. A high response was found in the parathymic lymph nodes (PTLN). Iv immunization gave rise to the development of AFC in the spleen, particularly of the IgM isotype. We failed to induce mucosal responses to PPS-3 antigen in the colon, irrespective of the route of immunization.

Peritoneal cell labelling: a study on the migration of macrophages and dendritic cells towards the gut.

In this study the migration of peritoneal cells was investigated by a fluorescence labelling technique. We found that peritoneal cells migrate to the subcapsular sinus and medulla of the parathymic lymph node (PTLN) and paratracheal lymph node (PTrLN). It was also observed that fluorescence labelled cells possibly granulocytes, macrophages and dendritic cells were found in the B cell follicles of Peyer patches and the dome area after intraperitoneal (ip) labelling. The implication of the migration of antigen presenting cells to the gut on the mucosal immune response is discussed.

Ontogeny of reticulum cells in the rat intestine and their possible role in the development of the lymphoid microenvironment.

Ontogeny of reticulum cells (RC) in the rat intestine in relation to the development of the gut-associated lymphoid tissue (GALT) was studied using a panel of monoclonal antibodies (mab) directed against RC in peripheral lymphoid organs, ED10-ED15. The mab ED10 specific for RC in the spleen T cell area, recognized an epitope on gut RC, which cells seem to be involved in the influx and accumulation of lymphocytes in the lamina propria and in Peyer's patches (PP) and proximal colonic lymphoid tissue (PCLT). The mab ED11 which recognizes RC in the T cell area and B cell follicles of spleen, stained follicular dendritic cells (FEC) in the B cell area of the mesenteric lymph node (MLN), PP and PCLT. The ED11 expression occurs earlier and reveals stronger staining in MLN as compared to those in PP and PCLT, suggesting the prominent role of MLN in the generation and proliferation of B cells in the gut mucosal immune system. The mab ED13 specific for RC in the B cell area of the lymph nodes, stained the basement membrane of the epithelium overlying PP and PCLT, and high endothelial venules (HEV), suggesting that this might be involved in providing the microenvironment for the development and differentiation of follicle-associated epithelium, and facilitating lymphocyte traffic. The mab ED12 specific for RC in the paracortex of peripheral lymph nodes, gave a diffuse nonspecific staining in the gut, whereas mab ED14 and ED15 are markers for common connective tissue cells. We conclude that the gut RC are morphologically and phenotypically heterogenous. ED10+, ED11+, and ED13+ RC are probably involved in the development of the gut lymphoid microenvironment.

The in situ immune response of the rat after intraperitoneal depletion of macrophages by liposome-encapsulated dichloromethylene diphosphonate.

This study concerns the contribution of peritoneal macrophages in vivo to local and systemic immune responses in the rat. Peritoneal macrophages as well as macrophages in the draining parathymic lymph nodes were selectively eliminated by intraperitoneal inoculation of dichloromethylene-diphosphonate-containing liposomes. This depletion resulted in an enhanced immune reaction to intraperitoneally administered trinitrophenyl keyhole limpet haemocyanin in the parathymic lymph nodes, as demonstrated by the higher numbers of specific anti-TNP antibody-forming cells in macrophage-depleted animals than in control animals from day 5 after immunization. The immune reaction peaked at day 7 and remained high until day 10. Specific antibody-forming cells were found occasionally in the mesenteric lymph nodes and spleen, but not in the mucosa of the gut or in the bronchus-associated lymphoid tissue. An elevated immune reaction found in parathymic lymph nodes associated with the depletion of local macrophages by liposome treatment indicates a regulatory role of peritoneal macrophages in local humoral immune response.

The effects of Peyer's patches inactivation in the rat on the development of antibody-forming cells to intestinal antigen.

The effects of Peyer's patch (PP) inactivation on local and systemic immune response in rats was investigated. A cauterization method has been developed to inactivate PP. Animals were primed intraperitoneally or intragastrically with trinitrophenyl-keyhole limpet haemocyanin (TNP-KLH) one day before cauterization, and were challenged intraintestinally two weeks later. The secondary immune response in the spleen, mesenteric lymph node (MLN) and intestinal villi was studied by immunohistochemistry. Histological observations on PP after inactivation showed that most T cells in the interfollicular area had disappeared, as had B cells in the follicle. T cells repopulated PP much slower than B cells. Complete recovery of PP occurred no earlier than 2 weeks after inactivation. The immunization experiments revealed higher numbers of anti-TNP antibody-forming cells (anti-TNP AFC) of IgM, IgG and IgA isotypes in the spleen of the PP-inactivated animals than in the controls. Very few anti-TNP AFC were found locally in the lamina propria of the intestinal villi or in the MLN in both groups. It is suggested that PP play a role in the regulation of systemic immune responses against intestinally-administered thymus-dependent antigen. Moreover, inactivation of PP could alter the antigen uptake by gut epithelium and the local antigen processing. As a result, an increased amount of antigen could reach the spleen eliciting a higher immune response.

The localization of macrophage subsets and dendritic cells in the gastrointestinal tract of the mouse with special reference to the presence of high endothelial venules. An immuno- and enzyme-histochemical study.

This study concerns the distribution of macrophages and dendritic cells (DC) in the gastrointestinal tract of the mouse. Heterogeneity of macrophage population was found by using the MOMA-1, MOMA-2, ERTR-9, Mac-1 and F4/80 monoclonal antibodies. MOMA-1, ERTR-9, Mac-1 and F4/80+ cells were detected mostly at the villous cores in the lamina propria of the villi, whereas MOMA-2+ cells were primarily found around the crypts at the base of the villi. These MOMA-2+ cells revealed a granular appearance throughout the cytoplasm and displayed a strong acid phosphatase (AcPh) activity. Few MOMA-2+ cells were seen at the top of the villi in the epithelium. Although MOMA-1 and ERTR-9+ cells have similar morphology and the same distribution patterns in the lamina propria, they are likely different populations, because in Peyer's patches (PP), MOMA-1+ cells were present, whereas ERTR-9+ cells could not be detected. Both populations displayed AcPh activity. Strongly stained Mac-1+ cells were abundantly seen in the lamina propria of the small intestine. F4/80+ cells were rare. NLDC-145+ cells with AcPh activity and weak Ia staining were also found. In the PP-associated villi and in the T-dependent area of PP, dendritic NLDC-145+ cells, which were strongly Ia positive, were detected. MIDC-8+ cells were found only in the T-dependent area. Few NLDC-145+ cells (dendritic cells) were found in the upper part of the oesophagus. These cells were also stained with the MIDC-8 antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

IgE responses in human gnathostomiasis.

Specific IgE antibody levels in the serum of patients with proven gnathostomiasis and in those with intermittent cutaneous migratory swellings were determined by the enzyme-linked immunosorbent assay (ELISA) using aqueous extracts of Gnathostoma spinigerum infective larvae as antigen. There was not only an elevation of specific IgE antibody levels but also a marked increase of total IgE in the serum of these patients. The mean levels of specific IgE antibody in both groups of patients were significantly higher than that of healthy controls (P less than 0.01). Only one of the 50 serum specimens tested had an ELISA reading that fell within the mean + 2 standard deviations of the control group, suggesting that the method would be useful with a high degree of reliability in confirming a clinical diagnosis of gnathostomiasis in humans. Compared with healthy controls, there was almost a 10-fold rise (P less than 0.01) in the total IgE in the serum of these patients, indicating that G. spinigerum infection potentiates IgE production similarly to many other nematode parasites.