PT - JOURNAL ARTICLE AU - R Duchmann AU - E May AU - M Heike AU - P Knolle AU - M Neurath AU - K-H Meyer zum Büschenfelde TI - T cell specificity and cross reactivity towards enterobacteria,<em>Bacteroides</em>,<em>Bifidobacterium</em>, and antigens from resident intestinal flora in humans AID - 10.1136/gut.44.6.812 DP - 1999 Jun 01 TA - Gut PG - 812--818 VI - 44 IP - 6 4099 - http://gut.bmj.com/content/44/6/812.short 4100 - http://gut.bmj.com/content/44/6/812.full SO - Gut1999 Jun 01; 44 AB - BACKGROUND T cell responses to normal intestinal bacteria or their products may be important in the immunopathogenesis of chronic enterocolitis.AIMS To investigate the T cell specificity and cross reactivity towards intestinal bacteria.PATIENTS/METHODS T cell clones were isolated with phytohaemagglutinin from peripheral blood and biopsy specimens of inflamed and non-inflamed colon from five patients with inflammatory bowel disease (IBD) and two controls. T cell clones were restimulated with anaerobicBacteroides andBifidobacteria species, enterobacteria, and direct isolates of aerobic intestinal flora. T cell phenotype was analysed by single-cell immunocyte assay.RESULTS Analysis of 96 T cell clones isolated from peripheral blood and biopsy specimens from two patients with IBD showed that bothBifidobacterium andBacteroides species specifically stimulate proliferation of CD4+TCRαβ+ T cell clones from both sites and that cross reactivity exists between these anaerobic bacteria and different enterobacteria. Analysis of 210 T cell clones isolated from three patients with IBD and two controls showed that indigenous aerobic flora specifically stimulate T cell clones from peripheral blood and biopsy specimens from a foreign subject. Some of these flora specific T cell clones were cross reactive with defined enterobacteria. In addition, T cell clones stimulated by their own indigenous aerobic flora were identified in patients with IBD.CONCLUSION Immune responses to antigens from the intestinal microflora involve a complex network of T cell specificities.IBDinflammatory bowel diseasePCRpolymerase chain reactionBsAbacteria from autologous intestine—that is, sonicates and mononuclear cells from the same subjectBsHbacteria from heterologous intestine—that is, sonicates and mononuclear cells from different subjectsTCRT cell receptor