Gastroenterology
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Reduced p27(kip1) expression is a marker of poor prognosis in colorectal neoplasia, and inactivation of p27 in mice (p27(Delta51/Delta51)) causes increased intestinal epithelial cell proliferation and small and large intestinal neoplasia in a diet-dependent manner. Here, we addressed the role of p27 in untransformed intestinal epithelial cells in vivo and the consequence of its targeted inactivation. ⋯ We propose that p27 contributes to intestinal epithelial homeostasis by regulating cdk2 activity in proliferating cells, thus gating cell cycle progression and suppressing intestinal neoplasia.
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Recognition of infection leads to induction of adaptive immunity through activation of antigen-presenting cells (APCs). Among APCs, dendritic cells (DCs) have the unique capacity to deliver antigens from the periphery to T cells in secondary lymphoid organs. ⋯ A principal pathway by which DCs sense H pylori and become activated is the TLR-dependent signaling cascade. In vivo, Myd88 signaling affects adaptive immunity to the bacterium.