INTERACTION OF LIPID A AND INNATE IMMUNE RECEPTORS IN NEISSERIA INFECTION

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 淋病奈瑟氏菌和奈瑟氏菌感染。脑膜炎是全世界的一个主要公共卫生问题。在奈瑟球菌感染患者中，细胞因子如TNF-α、IL-1 β、IL-6和IL-8的水平相对于临床疾病表现的严重程度而升高。 两种先天性免疫受体，toll样受体4（TLR 4）和在骨髓细胞上表达的触发受体（TREM），其在单核细胞、嗜中性粒细胞和粘膜上皮细胞上表达，被来自肠细菌的脂多糖（LPS）刺激，并且是对革兰氏阴性细菌感染的有效免疫应答所需的。 在参与奈瑟菌感染发病机制的重要毒力因子中，脂寡糖（LOS）被认为是诱导宿主对生物体的细胞因子应答的主要成分。 特别是，几项研究表明脂质A部分是奈瑟球菌LOS的生物活性成分。 我们假设，脂质A的酰化和磷酸化的异质性，这两者都已被证明会影响来自土方坐骨结肠的LPS的毒性，是奈瑟球菌LOS与TLR 4和TREM的不同反应性的基础，导致感染期间诱导细胞因子的程度不同。 基于TLR 4和TREM在识别细菌LPS中的关键作用，很明显，这些先天免疫受体对LOS信号的不适当反应可能在奈瑟氏球菌感染期间产生重要后果，导致过度反应，如淋球菌性盆腔炎和脑膜炎球菌性脓毒症。 在这个建议中，我们将测试的假设，在不同的奈瑟球菌菌株的LOS内的脂质A结构的自然变化是感染过程中诱导细胞因子的程度的主要决定因素。 为此，我们将确定脂质A分子的结构，从奈瑟球菌菌株显示可变的刺激TLR 4受体。 我们将使用化学、气相色谱、质谱和磁共振方法来确定脂质A分子的结构。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Infections due to Neisseria gonorrhoeae and N. meningitidis represent a major public health problem around the world. In patients with Neisserial infections, levels of cytokines such as TNF-alpha, IL-1beta, IL-6, and IL-8 are increased relative to the severity of the clinical disease presentation. Two innate immune receptors, toll-like receptor 4 (TLR4) and triggering receptor expressed on myeloid cells (TREM), which are expressed on monocytes, neutrophils, and mucosal epithelial cells, are stimulated by lipopolysaccharide (LPS) from enteric bacteria and are required for an efficient immune response to Gram-negative bacterial infections. Among the important virulence factors involved in the pathogenesis of Neisserial infections, the lipooligosaccharide (LOS) is believed to be a major component inducing host cytokine responses to the organisms. In particular, several studies have implicated the lipid A portion as the bioactive component of Neisserial LOS. We hypothesize that heterogeneity in the acylation and phosphorylation of the lipid A, both of which have been shown to influence the toxicity of LPS from Escherischia coli, underlies the differential reactivity of Neisserial LOS with TLR4 and TREM resulting in differences in degree to which cytokines are induced during infection. Based on the key role of TLR4 and TREM in the recognition of bacterial LPS, it is apparent that in inappropriate response by these innate immune receptors to LOS signals could have important consequences during Neisserial infections, leading to exaggerated response such as gonococcal pelvic inflammatory disease and meningococcal sepsis. In this proposal, we will test the postulate that natural variation in the lipid A structure within the LOS of different Neisserial strains is the major determinant of the degree to which cytokines are induced during infection. To this end, we will determine the structure of the lipid A molecules from Neisserial strains showing variable stimulation of the TLR4 receptor. We will use chemical, gas chromatography, mass spectrometry, and magnetic resonance methods to determine the structures of the lipid A molecules.