The innate and the adaptive BMS-777607 price immune responses lead to damaging inflammatory responses, but these responses may fail, allowing for persistence of many infections. Thus, developing new therapeutics and effective vaccines against H. pylori has proven to be arduous. In this manuscript, we will examine the advances in knowledge made in the past year in understanding the host immune response to H. pylori and the progress toward developing a vaccine. The host innate immune system plays a key role in the initiation and the subsequent progression of H. pylori-associated pathogenesis. Gastric

epithelial cells (GECs) are the primary target for H. pylori infection and actively contribute to the innate immune responses via signaling through pattern recognition receptors, such as Toll-like receptors (TLRs). GECs are the first point of contact for H. pylori and express TLRs that may activate an innate immune response. Although lipopolysaccharide (LPS) is the classical bacterial ligand for TLR-4, H. pylori-derived LPS has been reported to click here signal through TLR-2 and has low binding affinity for TLR-4. To further examine this, one study showed that H. pylori enzymes, LpxE and LpxF, desphosphorylate the lipid A of its LPS, leading to a decrease

in recognition by TLR-4 [1]. In another suggested mechanism of immune evasion, H. pylori was shown to inhibit macrophage release of nitric oxide in response to H. pylori LPS in a mouse model of infection [2]. H. pylori LPS was also shown to suppress TLR-4 signaling, but enhance IL-12 and IL-18 production [3], which was suggested

to be linked to the chronic inflammation commonly seen during infection. In further support for the role of H. pylori LPS signaling through TLR-2 instead of TLR-4, one group demonstrated that upon TLR-2 activation by LPS derived from H. pylori the TRIB3 protein was inhibited, which controls TLR-2-mediated NF-κB signaling, thus leading to increased NF-κB signaling Aldol condensation [4]. A further role of TLR-2 was shown in addition to TLR-5 expression by H. pylori on THP-1 monocytic leukemia cells resulted in a shift from cagPAI-dependent to cagPAI- independent signaling leading to the secretion of IL-8 and TNF-α [5]. In NK cells, TLR-2 was shown to be activated by H. pylori lipoprotein HpaA, leading to IFN-γ production in an IL-12 dependent manner [3, 6]. In further analysis of TLR-2 activation by H. pylori, urease was shown to activate TLR-2 on B cells, inducing autoantibodies and suggesting a link to autoimmune disorders [7]. Also of relevance clinically, a recent epidemiologic study demonstrated that genetic polymorphisms in TLR-5 may contribute to the H. pylori-associated gastric cancer in Chinese population [8]. Inflammation is a crucial player in the H. pylori immune response.

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