CELL BIOLOGY OF BCR MEDIATED ANTIGEN PROCESSING

描述（改编自申请人的摘要）：中心假设 在这个项目中要追求的是， 由B细胞引起的免疫反应发生在特化的亚细胞区室中。 初步 研究已经确定了两个被称为II类囊泡的候选隔室 （CIV）和多层II类囊泡（MCV）。 CIV包含两种 内化B细胞抗原受体（BCR）和II类分子， 这表明一部分内化的抗原-BCR复合物可能 从大量内吞途径转向CIIV，在那里加工和 将肽片段加载到II类分子上。 MCV是一个 不同的细胞内区室，也含有II类分子，如 以及未鉴定的46 kDa标记蛋白。 this project will use CIIV和MCV的生物化学纯化制剂，以阐明 这些专门的隔间在处理BCR相关抗原。 此外，各种BCR突变体将用于鉴定序列 负责将携带抗原的BCR分选为CIIV的决定簇 还有MCV。

DESCRIPTION (Adapted from the Applicant's Abstract): The central hypothesis to be pursued in this project is that the presentation of specific antigens by B cells occurs in a specialized subcellular compartment(s). Preliminary studies have identified two candidate compartments termed Class II vesicles (CIIV) and multilaminar Class II vesicles (MCV). CIIV contain both internalized B-cell antigen receptors (BCR) and Class II molecules, suggesting that a fraction of internalized antigen-BCR complexes may be diverted from the bulk endocytic pathway into CIIV, where processing and loading of peptide fragments onto Class II molecules occurs. MCV are a distinct intracellular compartment that also contains Class II molecules, as well as an unidentified 46 kDa marker protein. This project will use biochemically purified preparations of CIIV and MCV to clarify the roles of these specialized compartments in the processing of BCR-associated antigens. In addition, various BCR mutants will be used to identify the sequence determinants responsible for the sorting of antigen-bearing BCR into CIIV and MCV.