FLAGELLIN REACTIVITY AS A MARKER FOR A SUBTYPE OF CROHN'S DISEASE

对肠道炎症动物模型的研究表明，CD是对共生细菌的异常免疫反应的结果。在这些模型中，疾病的发展和进展取决于T细胞对特定共生细菌的反应性。鞭毛蛋白CBir1已被确定为优势抗原，在导致小鼠结肠炎的先天和获得性免疫反应中发挥作用。50%的CD患者是 抗CBir1+，而溃疡性结肠炎、其他炎症性G1疾病患者或对照组为抗CBir。我们已经证明了对特定细菌抗原的选择性耐受性丧失，而多重和高水平的血清反应与侵袭性表型有关，而无反应与良性疾病病程有关。我们的初步数据表明，血清对CBir1的反应性与先前定义的抗原无关，即OMPC，1-2， 而CBir1的表达与ASCA患者有关，甚至与ASCA患者有关--除了抗OMPC和抗L2‘外。数据表明，结肠炎易感小鼠对鞭毛信号TLR5的天然免疫反应减弱，对鞭毛抗原的T细胞反应夸大。在对结肠炎耐药的菌株中，情况似乎正好相反。我们的假设是，对鞭毛蛋白有高幅度抗体反应的CD患者树突状细胞和T细胞反应的变化与在小鼠中看到的相似，并且这些变化是基于遗传变异，所有这些都强调了与患者不同的临床表型。 缺乏这样的回应。我们将通过1.定义CBir1反应性CD患者的表型，方法是将抗CBir1表达的存在和水平与疾病的解剖位置和其他炎症标志物相关联，确定抗体在病程中何时产生，确定炎症类型，即是否为Th1，然后确定抗CBir1表达是否可以预测Th1修饰剂或抗生素的治疗结果。我们将进一步确定CBir1的特异性表位(S)是否 分子与病理亚型有关。2.通过检测13个参与先天免疫通路和Th1免疫通路的候选基因，确定与抗CBir1反应的大小相关的等位基因变异，以确定与抗CBIM表达相关的Th1炎症的遗传基础。3.明确单核细胞和单核细胞来源的树突状细胞对鞭毛蛋白、CpG和内毒素的天然免疫应答。4.确定同一患者的T细胞对CBir1的应答是否与血清应答的大小呈正相关，与先天免疫应答的大小呈负相关。

Investigations of animal models of intestinal inflammation suggest that CD is a result of an aberrant immunologic response to commensal bacteria. In these models, disease development and progression hinge on the presence of T-cell reactivity to specific commensal bacteria. The flagellin, CBir1 has been identified as a dominant antigen with a role in both the innate and adaptive immune responses, which lead to colitis in murine models. 50% of patients with CD are anti-CBir1+, whereas patients with ulcerative colitis, other inflammatory Gl diseases or controls are anti-CBir. We have demonstrated selective loss of tolerance to specific bacterial antigens, and that multiple and high-level serum responses are associated with aggressive phenotypes while no response is associated with a benign disease course. Our preliminary data show that serum reactivity to CBir1 is independent of previously defined antigens, i.e. OmpC, 1-2, oligomannan, and that CBir1 expression is associated with ASCA- patients, and even those who are ASCA- in addition to being anti-OmpC- and anti-l2'. Data has shown that colitis-susceptible mice have a muted innate immune response to flagellin signaling of TLR5 and an exaggerated T-cell response to flagellin antigens. In colitis resistant strains, the opposite appears to be true. Our hypothesis Is that CD patients with high amplitude antibody response to flagellin have changes In dendritic cell and T-cell responses similar to those seen In mice and that these are based on genetic variations, all of which underline a clinical phenotype distinct from patients that lack such responses. We will test this hypothesis by 1. Defining the phenotype of CBir1-reactive CD patients by correlating the presence and the level of anti-CBir1 expression with anatomic location of disease and other inflammatory markers, determining when in the disease course the antibodies develop, determine the type of inflammation, i.e., whether it is Th1, and then determine whether anti-Cbirl expression can predict treatment outcomes with Th1 modifying agents or response to antibiotics. We will further determine whether specific epitope(s) of the CBir1 molecule are associated with pathologic subtypes. 2. Determining the genetic basis for the Th1 inflammation associated with anti-CBiM expression by testing 13 candidate genes involved in the innate and Th1 immune pathways to define allelic variations related to the magnitude of anti-CBir1 responses. 3. Defining the innate immune responses of monocytes and monocyte-derived dendritic cells to flagellin, CPG and LPS. 4. Determining whether T-cell responses to CBir1 are positively correlated with the magnitude of serum responses and negatively correlated with the magnitude of innate immune responses within the same patient.