ANTIGEN PRESENTATION BY CLASS IB MOLECULE QA-1

非经典I类（I β）基因包括大多数的I类基因， 老鼠和人。直到最近才变得明显， 这些分子在免疫应答中起重要作用。 我们建议 将我们的研究集中在鼠I β类分子Qa-1上。 该抗原 是多态的，普遍表达，并且已知呈现合成的 聚合物与γ δ T细胞以及与肽剥夺的相互作用 从M.牛 Qa-1的F口袋中的保守残基 肽结合沟不同于Ia类共有的那些。 因此，我们的研究将集中在Qa-1识别的肽 特异性细胞毒性T淋巴细胞（CTL），目的是增加我们的 了解I类中的抗原加工和呈递 通路 一种这样的肽由称为Qdm（Qa-1）的基因控制 行列式修饰符）。 我们已经确定Qdm-肽编码为 Ia类D-末端等位基因，Dk除外，以及衍生的合成肽 从这些分子中，由Qa 1b呈递给我们的Qa 1b抗Qa-1b（Qdm-1）。 依赖性）CTL克隆。 我们将描述哪种肽与 从Qa-1b淋巴母细胞洗脱的天然肽，并确定 肽中对结合Qa-1b很重要的残基。 QDM- 肽也从Qa-1a淋巴母细胞洗脱。 所以我们会 产生Qdm依赖性Qa-1b抗Qa-1a CTL克隆，并确定它们是否 识别与“a抗b”克隆相同的肽，以及 肽以相同的方式结合这两个Qa-1等位基因。 Qdm阴性 (Dk)肽也将被表征，因为Qdm依赖性CTL可以被 在H-2k菌株中产生。 Vbeta和Valpha T细胞的CDR 3区 这种独特的同种异体反应性和肽特异性CTL的受体 克隆将被测序。 作为这些实验的结果，我们将定义 与Qa-1结合并被特异性CTL识别的第一肽。 此外，这些独特的肽特异性 同种异体反应性CTL将使我们能够确定相同的肽是如何 由同种异体抗原的两个不同等位基因呈现，并比较如何呈现 肽与同种异体抗原影响T细胞受体识别。 Fee肽在RYA-S（Tap-2缺陷型）细胞上不表达， Tap-1敲除动物的淋巴母细胞。 令人惊讶的是， 包含在D-末端抗原的信号肽中，并与其他 报道了前导肽在膜I类分子上表达 在缺乏转运功能的细胞中。 因此，我们将使用QDM- 肽作为探针，以检查前导序列的抗原加工方面， 衍生表位。 这将提供新的信息，不仅对 这些抗原的加工，而且对前导肽的运输 在细胞内。

Nonclassical class I (Ibeta) genes comprise most of the class I genes of mouse and man. Only recently has it become apparent that at least some of these molecules play important roles in the immune response. We propose to focus our studies on the murine class Ibeta molecule, Qa-1. This antigen is polymorphic, expressed ubiquitously, and known to present a synthetic polymer to gammadelta T cells as well as interact with a peptide deprived from Hsp-65 from M. bovis. Conserved residues in the F pocket of the Qa-1 peptide binding groove differ from those of the class Ia consensus. Therefore, our studies will focus on peptides that are recognized by Qa-1 specific cytotoxic T lymphocytes (CTL) with the aim of increasing our understanding of antigen processing and presentation in the class I pathway. One such peptide is controlled by a gene(s) termed Qdm (Qa-1 determinant modifier). We have identified the Qdm-peptide as being encoded by class Ia D-end alleles, except for Dk, and synthetic peptides derived from these molecules are presented by Qa1b to our Qa1b anti-Qa-1b (Qdm- dependent) CTL clones. We will characterize which peptide is identical to the natural peptide eluted from Qa-1b lymphoblasts, and determine the residues in the peptide that are important for binding to Qa-1b. The Qdm- peptide is also eluted from Qa-1a lymphoblasts. Therefore, we will generate Qdm-dependent Qa-1b anti-Qa-1a CTL clones and determine if they recognize the same peptide as the "a anti-b" clones, as well as whether the peptide binds these two Qa-1 alleles in the same manner. The Qdm-negative (Dk) peptide will also be characterized since Qdm-dependent CTL can be generated in H-2k strains. The CDR3 region of the Vbeta and Valpha T cell receptors from this unique panel of alloreactive and peptide-specific CTL clones will be sequenced. As a result of these experiments we will define the first peptide(s) that binds to Qa-1 and is recognized by specific CTL. In addition, the availability fee these unique peptide-specific alloreactive CTL will allow us to determine how the same peptide is presented by two different alleles of an alloantigen as well as compare how peptide vs. alloantigen influence T cell receptor recognition. The Fee peptide is not expressed on RYA-S (Tap-2 defective) cells or lymphoblasts from Tap-1knockout animals. Surprisingly, the peptide is contained in the signal peptide of D-end antigens, and contrasts with other reports where leader peptides are expressed on mambrane class I molecules in cells lacking transporter function. Therefore, we will use the Qdm- peptide as a probe to examine aspects of antigen processing of leader- derived epitopes. This will provide novel information not only on the processing of these antigens, but also on the traffic of leader peptides within the cell.