In diseases with a strong association with an HLA haplotype, identification of relevant T cell ep... more In diseases with a strong association with an HLA haplotype, identification of relevant T cell epitopes may allow alteration of the pathologic process. In this report we use a reverse immunogenetic approach to predict possible HLA class II-restricted T cell epitopes by using complete pool sequencing data. Data from HLA-DR2(B1*1501), -DR3(B1*0301), -DQ2(A1*0501, B1*0201), and -DQ8(A1*0301, B1*0302) alleles were used by a computer program that searches a candidate protein to predict ligands with a relatively high probability of being processed and presented. This approach successfully identified both known T cell epitopes and eluted single peptides from the parent protein. Furthermore, the program identified ligands from proteins in which the binding motif of the HLA molecule was unable to do so. When the information from the nonbinding N- and C-terminal regions in the pool sequence was removed, the ability to predict several ligands was markedly reduced, particularly for the HLA-DQ a...
Expression of adhesion molecules is increased in inflamed colonic mucosa, but little is known abo... more Expression of adhesion molecules is increased in inflamed colonic mucosa, but little is known about their functional activity in vascular endothelium. We studied in situ nitroblue tetrazolium reducing activity and expression of E-selectin, ICAM-1, CD31, and VCAM-1 by immunohistochemistry in the same biopsy specimen in controls and patients with ulcerative colitis (UC). VCAM-1 expression was negative in mucosal vessels. E-selectin-positive vessels were significantly increased in endoscopically active colitis compared with normal mucosa. ICAM-1-positive vessels were consistently found in normal, quiescent UC and active UC. CD31-positive vessels were not significantly increased in quiescent UC and active UC compared with control. Only E-selectin significantly correlated with the histologic grade of inflammation. Nitroblue tetrazolium reducing vessels were increased in inflamed mucosa, and these vessels expressed ICAM-1 and CD31. E-selectin positivity in association with nitroblue tetrazolium reduction was mainly seen in the large mucosal vessels, but capillaries showing nitroblue tetrazolium reduction were rarely positive for E-selectin. Phenotypic and functional activation of vascular endothelium might be involved in the recruitment of leukocytes and tissue destruction of inflamed colonic mucosa.
1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known t... more 1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known to stimulate anion secretion in the distal colon. Since there are regional differences in ion transport within the colon, the influence of platelet-activating factors on ion transport and epithelial permeability has been studied in rabbit caecum and distal colon mounted in Ussing chambers. 2. The effect of platelet-activating factor (1–50 nmol/l) on net electrogenic ion transport was to stimulate a biphasic increase in short-circuit current in the distal colon but not in the caecum. The platelet-activating factor-induced rise in short-circuit current was shown by ion replacement and pharmacological inhibitor studies to be consistent with chloride and bicarbonate secretion in the early phase, but with chloride secretion alone in the later phase. The effect on ion transport was specific and reversible and was enhanced by 0.25% BSA. 3. Colonic permeability, assessed by transmucosal resistanc...
Mononuclear cell (MNC) populations isolated from intestinal mucosa, mesenteric lymph nodes, and p... more Mononuclear cell (MNC) populations isolated from intestinal mucosa, mesenteric lymph nodes, and peripheral blood have been assessed for their natural killer (NK) (Leu-7+) cell proportions and NK cell activity against K-562 erythroleukemic target cells. In peripheral blood, normal proportions of Leu-7+ cells were found in patients with Crohn's disease or ulcerative colitis, whereas increased proportions in colorectal carcinoma may have been related to the higher mean age of these patients. Low proportions of Leu-7+ cells (less than 3%) were present in intestinal MNCs in Crohn's disease, ulcerative colitis, colon cancer, and miscellaneous intestinal diseases. All groups of patients had diminished NK activity of peripheral blood MNCs compared with a group of healthy controls. Intestinal NK cell activity from histologically normal mucosa correlated with autologous peripheral blood NK cell activity (p less than 0.001) but no such correlation was seen for patients with inflammatory bowel disease. Mucosal or nodal NK cell activity showed a wide range of activity but did not relate to the underlying disease, mucosal histopathology, drug therapy, or, in patients with cancer, Dukes' grading. Intestinal MNCs from all patient groups responded to stimulation with lymphoblastoid interferon, except in a small number of patients whose unstimulated activity was not detectable. In conclusion, the NK cell on intestinal mucosa behaves similarly in various intestinal diseases. However, the disparity between NK activity of autologous peripheral blood and intestinal MNCs in inflammatory bowel disease highlights the difficulty in extrapolating peripheral blood findings to mucosal immune events.
1. This study investigates the acetylation of 5′-aminosalicylic acid by isolated human colonic ep... more 1. This study investigates the acetylation of 5′-aminosalicylic acid by isolated human colonic epithelial cells. 2. After incubation of intact cells with 0.1 mmol/l 5-aminosalicylic acid, N-acetyl-5-aminosalicylic acid was detected in a concentration of 141 (± 23.8 sem) nmol/g dry weight in the incubation medium, and 34.8 (± 5.5 sem) nmol/g dry weight intracellularly. No unchanged 5-aminosalicylic acid was detected inside the cell. 3. Acetylation of 5-aminosalicylic acid by a cell homogenate was very poor, but the addition of 1 mmol/l acetyl-CoA resulted in complete conversion of 0.1 mmol/l 5-aminosalicylic acid to N-acetyl-5-aminosalicylic acid. 4. N-Acetyltransferase activity was detected in the cytosol, with a mean of 3.3 nmol min−1 mg−1 of protein. There was no N-acetyltransferase activity in the brush border. There was no difference in enzyme activity between epithelial cells derived from normal, Crohn's disease or ulcerative colitis patients. 5. Preliminary characterizatio...
Whether or not the immune system initiates CD, it can be seen to play a role in the natural histo... more Whether or not the immune system initiates CD, it can be seen to play a role in the natural history of the disease. Genetic susceptibility to CD has been shown to be linked to the HLA, DQw2 and it appears that other genes within the MHC further contribute to disease susceptibility. The search for other immune response genes that may
European journal of gastroenterology & hepatology, 1997
All patients with ileal pouch-anal anastomosis (IPAA) have some degree of villous atrophy, mucin ... more All patients with ileal pouch-anal anastomosis (IPAA) have some degree of villous atrophy, mucin changes and chronic inflammation. The mechanism underlying these changes is unknown. This study investigates the hypothesis that luminal factor(s) may affect epithelial cells in in-vitro studies. IPAA dialysate from eight patients with prior ulcerative colitis was assessed. The effect of the dialysate on epithelial cell (i-407, HT-29 and CaCo-2) proliferation (3H-thymidine incorporation) and cytotoxicity (51-chromium release) was determined. Bile acid(s) at concentrations measured in IPAA dialysate were assessed in isolation and in combination for cytotoxicity against CaCo-2 cells. The effect of dialysate and bile acids on immature and mature CaCo-2 monolayer cytotoxicity, transepithelial electrical resistance (TEER) and histology was investigated. IPAA dialysate is antiproliferative and cytotoxic to the cell lines. At concentrations present in dialysate chenodeoxycholic acid and deoxych...
Expert review of gastroenterology & hepatology, 2012
The etiology of inflammatory bowel disease is unknown but available evidence suggests that a dere... more The etiology of inflammatory bowel disease is unknown but available evidence suggests that a deregulated immune response towards the commensal bacterial flora is responsible for intestinal inflammation in genetically predisposed individuals. IL-23 promotes expansion and maintenance of Th17 cells, which secrete the proinflammatory cytokine IL-17 and have been implicated in the pathogenesis of many chronic inflammatory disorders. Recent studies have shown that IL-23 also acts on cells of the innate immune system that can contribute to inflammatory cytokine production and tissue inflammation. A role for the IL-23/IL-17 pathway in the pathogenesis of chronic intestinal inflammation in inflammatory bowel disease has emerged from both animal and human studies. Here we aim to review the recent advances in this rapidly moving field.
In diseases with a strong association with an HLA haplotype, identification of relevant T cell ep... more In diseases with a strong association with an HLA haplotype, identification of relevant T cell epitopes may allow alteration of the pathologic process. In this report we use a reverse immunogenetic approach to predict possible HLA class II-restricted T cell epitopes by using complete pool sequencing data. Data from HLA-DR2(B1*1501), -DR3(B1*0301), -DQ2(A1*0501, B1*0201), and -DQ8(A1*0301, B1*0302) alleles were used by a computer program that searches a candidate protein to predict ligands with a relatively high probability of being processed and presented. This approach successfully identified both known T cell epitopes and eluted single peptides from the parent protein. Furthermore, the program identified ligands from proteins in which the binding motif of the HLA molecule was unable to do so. When the information from the nonbinding N- and C-terminal regions in the pool sequence was removed, the ability to predict several ligands was markedly reduced, particularly for the HLA-DQ a...
Expression of adhesion molecules is increased in inflamed colonic mucosa, but little is known abo... more Expression of adhesion molecules is increased in inflamed colonic mucosa, but little is known about their functional activity in vascular endothelium. We studied in situ nitroblue tetrazolium reducing activity and expression of E-selectin, ICAM-1, CD31, and VCAM-1 by immunohistochemistry in the same biopsy specimen in controls and patients with ulcerative colitis (UC). VCAM-1 expression was negative in mucosal vessels. E-selectin-positive vessels were significantly increased in endoscopically active colitis compared with normal mucosa. ICAM-1-positive vessels were consistently found in normal, quiescent UC and active UC. CD31-positive vessels were not significantly increased in quiescent UC and active UC compared with control. Only E-selectin significantly correlated with the histologic grade of inflammation. Nitroblue tetrazolium reducing vessels were increased in inflamed mucosa, and these vessels expressed ICAM-1 and CD31. E-selectin positivity in association with nitroblue tetrazolium reduction was mainly seen in the large mucosal vessels, but capillaries showing nitroblue tetrazolium reduction were rarely positive for E-selectin. Phenotypic and functional activation of vascular endothelium might be involved in the recruitment of leukocytes and tissue destruction of inflamed colonic mucosa.
1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known t... more 1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known to stimulate anion secretion in the distal colon. Since there are regional differences in ion transport within the colon, the influence of platelet-activating factors on ion transport and epithelial permeability has been studied in rabbit caecum and distal colon mounted in Ussing chambers. 2. The effect of platelet-activating factor (1–50 nmol/l) on net electrogenic ion transport was to stimulate a biphasic increase in short-circuit current in the distal colon but not in the caecum. The platelet-activating factor-induced rise in short-circuit current was shown by ion replacement and pharmacological inhibitor studies to be consistent with chloride and bicarbonate secretion in the early phase, but with chloride secretion alone in the later phase. The effect on ion transport was specific and reversible and was enhanced by 0.25% BSA. 3. Colonic permeability, assessed by transmucosal resistanc...
Mononuclear cell (MNC) populations isolated from intestinal mucosa, mesenteric lymph nodes, and p... more Mononuclear cell (MNC) populations isolated from intestinal mucosa, mesenteric lymph nodes, and peripheral blood have been assessed for their natural killer (NK) (Leu-7+) cell proportions and NK cell activity against K-562 erythroleukemic target cells. In peripheral blood, normal proportions of Leu-7+ cells were found in patients with Crohn's disease or ulcerative colitis, whereas increased proportions in colorectal carcinoma may have been related to the higher mean age of these patients. Low proportions of Leu-7+ cells (less than 3%) were present in intestinal MNCs in Crohn's disease, ulcerative colitis, colon cancer, and miscellaneous intestinal diseases. All groups of patients had diminished NK activity of peripheral blood MNCs compared with a group of healthy controls. Intestinal NK cell activity from histologically normal mucosa correlated with autologous peripheral blood NK cell activity (p less than 0.001) but no such correlation was seen for patients with inflammatory bowel disease. Mucosal or nodal NK cell activity showed a wide range of activity but did not relate to the underlying disease, mucosal histopathology, drug therapy, or, in patients with cancer, Dukes' grading. Intestinal MNCs from all patient groups responded to stimulation with lymphoblastoid interferon, except in a small number of patients whose unstimulated activity was not detectable. In conclusion, the NK cell on intestinal mucosa behaves similarly in various intestinal diseases. However, the disparity between NK activity of autologous peripheral blood and intestinal MNCs in inflammatory bowel disease highlights the difficulty in extrapolating peripheral blood findings to mucosal immune events.
1. This study investigates the acetylation of 5′-aminosalicylic acid by isolated human colonic ep... more 1. This study investigates the acetylation of 5′-aminosalicylic acid by isolated human colonic epithelial cells. 2. After incubation of intact cells with 0.1 mmol/l 5-aminosalicylic acid, N-acetyl-5-aminosalicylic acid was detected in a concentration of 141 (± 23.8 sem) nmol/g dry weight in the incubation medium, and 34.8 (± 5.5 sem) nmol/g dry weight intracellularly. No unchanged 5-aminosalicylic acid was detected inside the cell. 3. Acetylation of 5-aminosalicylic acid by a cell homogenate was very poor, but the addition of 1 mmol/l acetyl-CoA resulted in complete conversion of 0.1 mmol/l 5-aminosalicylic acid to N-acetyl-5-aminosalicylic acid. 4. N-Acetyltransferase activity was detected in the cytosol, with a mean of 3.3 nmol min−1 mg−1 of protein. There was no N-acetyltransferase activity in the brush border. There was no difference in enzyme activity between epithelial cells derived from normal, Crohn's disease or ulcerative colitis patients. 5. Preliminary characterizatio...
Whether or not the immune system initiates CD, it can be seen to play a role in the natural histo... more Whether or not the immune system initiates CD, it can be seen to play a role in the natural history of the disease. Genetic susceptibility to CD has been shown to be linked to the HLA, DQw2 and it appears that other genes within the MHC further contribute to disease susceptibility. The search for other immune response genes that may
European journal of gastroenterology & hepatology, 1997
All patients with ileal pouch-anal anastomosis (IPAA) have some degree of villous atrophy, mucin ... more All patients with ileal pouch-anal anastomosis (IPAA) have some degree of villous atrophy, mucin changes and chronic inflammation. The mechanism underlying these changes is unknown. This study investigates the hypothesis that luminal factor(s) may affect epithelial cells in in-vitro studies. IPAA dialysate from eight patients with prior ulcerative colitis was assessed. The effect of the dialysate on epithelial cell (i-407, HT-29 and CaCo-2) proliferation (3H-thymidine incorporation) and cytotoxicity (51-chromium release) was determined. Bile acid(s) at concentrations measured in IPAA dialysate were assessed in isolation and in combination for cytotoxicity against CaCo-2 cells. The effect of dialysate and bile acids on immature and mature CaCo-2 monolayer cytotoxicity, transepithelial electrical resistance (TEER) and histology was investigated. IPAA dialysate is antiproliferative and cytotoxic to the cell lines. At concentrations present in dialysate chenodeoxycholic acid and deoxych...
Expert review of gastroenterology & hepatology, 2012
The etiology of inflammatory bowel disease is unknown but available evidence suggests that a dere... more The etiology of inflammatory bowel disease is unknown but available evidence suggests that a deregulated immune response towards the commensal bacterial flora is responsible for intestinal inflammation in genetically predisposed individuals. IL-23 promotes expansion and maintenance of Th17 cells, which secrete the proinflammatory cytokine IL-17 and have been implicated in the pathogenesis of many chronic inflammatory disorders. Recent studies have shown that IL-23 also acts on cells of the innate immune system that can contribute to inflammatory cytokine production and tissue inflammation. A role for the IL-23/IL-17 pathway in the pathogenesis of chronic intestinal inflammation in inflammatory bowel disease has emerged from both animal and human studies. Here we aim to review the recent advances in this rapidly moving field.
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