[PubMed] [Google Scholar] 11. of immune cells into infected colonic tissue ACX-362E and greater levels of mucosal hyperplasia and the cytokines tumor necrosis factor alpha and gamma interferon. Surprisingly, despite being unable to eliminate contamination, p50?/? mice showed markedly higher levels of anti-IgG and IgM, suggesting that antibody alone is not responsible for bacterial clearance. These data also demonstrate that non-NF-B-dependent defenses are insufficient to control contamination, and hence, the NF-B p50 subunit is critical for defense against this noninvasive pathogen. Enteropathogenic (EPEC) and enterohemorrhagic (EHEC) are highly adapted enteropathogens that successfully colonize the host’s gastrointestinal tract via the formation of attaching-and-effacing (A/E) lesions (13). EPEC is usually a major cause of infantile diarrhea in ACX-362E the developing world, whereas EHEC is usually a food-borne pathogen in developed countries ACX-362E responsible for bloody diarrhea and hemolytic uremic syndrome due to the action of Shiga toxin (13). EPEC and EHEC exhibit thin host specificity, and mice are by and large resistant to contamination (21). The lack of a simple small-animal model to simulate an in vivo situation makes it hard to study EPEC and EHEC pathogenesis. In contrast, is usually a natural mouse pathogen that shares many virulence factors with EPEC and EHEC and relies on A/E lesion formation for colonization and contamination of the murine gastrointestinal mucosa (22). As a result, has become a popular surrogate model for in vivo studies, providing the ability to manipulate both the pathogen (7) and the host (27), and interesting insights have been gained into the in vivo functions of many gene products that are common to have recently been implicated in diarrhea using the mouse model (8, 18, 28). shows a remarkable ability to colonize the murine colon, with over 109 bacteria present during the peak of contamination. However, by day 21 post-oral challenge, is usually cleared ACX-362E from your gastrointestinal tracts of normal mice (31). Studies have shown that both innate and adaptive immune responses are required for immunity (5, 6, 15, 19, 27), with CD4 T-cell-dependent antibody responses believed to be central to clearance (5). Contamination of mice with elicits a mucosal TH1 immune response (12) very similar to mouse models of inflammatory bowel disease. Nuclear factor kappa B (NF-B) is usually of crucial importance in the activation and regulation of the immune response (16). It is ubiquitously expressed in most cell types and regulates a variety of genes responsible for immune function and inflammation (23, 26). NF-B is considered crucial in maintaining intestinal inflammation during host defense (23), and a high level of activation is usually thought to be a causative factor in the development of colitis and chronic inflammatory bowel disease (20, 24). Thus, NF-B has become a potential therapeutic target in the control of chronic intestinal inflammation. NF-B is usually a transcription factor composed of homodimers and heterodimers of Rel proteins, of which you will find five users in mammalian cells (NF-B1 [p50], NF-B2 [p52], RelA [p65], c-Rel, and RelB) (16). While NF-B is usually most commonly a heterodimer composed of p50 and p65 subunits, the various hetero- and homodimers of NF-B have different tissue expression patterns, binding specificities, and interactions, indicating discrete functions in the immune response (17). NF-B dimers are held in the cytoplasm in an inactive state by inhibitory proteins known as IBs. NF-B activation entails the signal-induced phosphorylation and degradation of IB molecules, which in turn releases NF-B to translocate into the nucleus and bind to the response elements of target promoters (16). Recently, Wang and colleagues exhibited that NF-B activity increased dramatically 12 days postinfection (p.i.) of Swiss-Webster mice with (30). Furthermore, they showed that NF-B activation during contamination predominantly involved p50/p65 heterodimer formation, but also p50/p50 homodimers. Mice Rabbit polyclonal to ZNF346 with targeted deletions of the immune system have proved extremely useful in relating particular arms of the immune response to immunity and pathology. Knockout of the p65 subunit.