CD4+ T cell affinity for self and foreign antigens in the CNS

迄今为止，我们评估CD 4 + T细胞频率和亲和力的最佳工具是肽：MHC （pMHC）四聚体或功能测定;这两种方法都不能有效地鉴定对一种抗原的所有应答细胞。 特殊抗原这与CD 8 + T细胞相反，这些技术证明更准确。 通常，II类抗原的pMHC四聚体难以产生并鉴定小百分比的pMHC四聚体。 应答性CD 4 + T细胞，尤其是当抗原来源于自身蛋白时。其原因是 四聚体是基于亲和力的，如果亲和力太低，那么四聚体在评估生物活性中的用途有限。 功能性应答也低估了抗原反应性CD 4 + T细胞的数量。的情况下 例如，在针对髓鞘抗原的应答中， 使用强力药物，如PMA和离子霉素，打击T细胞信号级联 并且可能与响应抗原本身而产生的细胞因子几乎没有相关性。更好地评估 为了确定应答的CD 4 + T细胞的范围，我们已经开始使用基于微量移液器的亲和力测定。我们报告 这是在评估CD 4 + T细胞对髓磷脂的频率和亲和力方面的一个重大进展， 或病毒抗原。因此，第一次有可能跟踪CD 4 + T细胞的亲和力范围。 疾病进展期间的反应。我们的初步发现导致了以下中心假设， CD 4 + T细胞亲和力谱直接影响疾病结果和免疫介导的组织损伤， CNS。提出了三个具体目标来检验这一假设，重点是对自身免疫特异性的CD 4 + T细胞。 抗原髓鞘少突胶质细胞糖蛋白和病原体相关淋巴细胞性脉络丛脑膜炎病毒 抗原 目的1-确定慢性自身免疫性疾病和病毒感染过程中CD 4 + T细胞的亲和力。 感染 目的2-确定T细胞亲和力和效应表型之间的联系。 目的3-确定高亲和力T细胞与低亲和力T细胞对体内发现的抗原的反应贡献 CNS。

To date, our best tools for assessing the frequency and affinity of CD4+ T cells have been peptide:MHC (pMHC) tetramers or functional assays; neither of which effectively identify all of the responding cells to a particular antigen. This is in contrast to CD8+ T cells where these techniques prove more accurate. Generally, pMHC tetramers for class II antigens are difficult to produce and identify a small percentage of responding CD4+ T cells especially when antigen is derived from self proteins. The reason for this is that tetramer is based on affinity and if affinity is too low, then the tetramer is of limited use in assessing the response Functional responses also underestimate the number of antigen reactive CD4+ T cells. In the case of responses directed against myelin antigens for instance, the effector cytokine response is often determined using strong pharmacologic agents such as PMA and ionomycin, which hammer the T cell signaling cascade and may have little relevance to the cytokines being produced in response to antigen itself. To better assess the range of responding CD4+ T cells, we have begun to use micropipette based affinity assay. We report here a major advancement in assessment in the frequency and affinity of CD4+ T cells directed against myelin or viral antigens. Therefore for the first time, it is possible to track the range of affinities of a CD4+ T cells response during disease progression. Our preliminary findings have led to the following central hypothesis that the CD4+ T cell affinity profile directly impacts disease outcome and immune mediated tissue damage in the CNS. Three specific aims are proposed to test this hypothesis focused on CD4+ T cells specific for self antigen myelin oligodendrocyte glycoprotein and pathogen associated lymphocytic choriomeningitis virus antigens. Aim 1- Identify the affinity of CD4+ T cells over the course of chronic autoimmune disease and viral infection. Aim 2- Define the connection between T cell affinity and effector phenotype. Aim 3- Establish the contribution of high versus low affinity T cells in response to antigens found in the CNS.