Binds peptides derived from antigens that access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for recognition by the CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mostly by degradation of proteins that access the endocytic route, where they are processed by lysosomal proteases and other hydrolases. Exogenous antigens that have been endocytosed by the APC are thus readily available for presentation via MHC II molecules, and for this reason this antigen presentation pathway is usually referred to as exogenous. As membrane proteins on their way to degradation in lysosomes as part of their normal turn-over are also contained in the endosomal/lysosomal compartments, exogenous antigens must compete with those derived from endogenous components. Autophagy is also a source of endogenous peptides, autophagosomes constitutively fuse with MHC class II loading compartments. In addition to APCs, other cells of the gastrointestinal tract, such as epithelial cells, express MHC class II molecules and CD74 and act as APCs, which is an unusual trait of the GI tract. To produce a MHC class II molecule that presents an antigen, three MHC class II molecules (heterodimers of an alpha and a beta chain) associate with a CD74 trimer in the ER to form a heterononamer. Soon after the entry of this complex into the endosomal/lysosomal system where antigen processing occurs, CD74 undergoes a sequential degradation by various proteases, including CTSS and CTSL, leaving a small fragment termed CLIP (class-II-associated invariant chain peptide). The removal of CLIP is facilitated by HLA-DM via direct binding to the alpha-beta-CLIP complex so that CLIP is released. HLA-DM stabilizes MHC class II molecules until primary high affinity antigenic peptides are bound. The MHC II molecule bound to a peptide is then transported to the cell membrane surface. In B-cells, the interaction between HLA-DM and MHC class II molecules is regulated by HLA-DO. Primary dendritic cells (DCs) also to express HLA-DO. Lysosomal microenvironment has been implicated in the regulation of antigen loading into MHC II molecules, increased acidification produces increased proteolysis and efficient peptide loading.
产品描述
该HLA-DRA ELISA Kit (Human)的产品描述请参考该产品的说明书
产品特点
ELISA试剂盒
保存建议
Store as indicated in product manual.
其他
Aviva Systems Biology总部位于加利福尼亚州圣迭戈,在中国北京设有办公室,专注于为研究需求提供多克隆和单克隆抗体、ELISA试剂盒、蛋白质和定制服务。Aviva Systems Biology生产了24,000种经过验证的多克隆抗体,并提供近20,000种ELISA试剂盒,定制实验室服务包括蛋白表达和纯化、抗体开发,以及ELISA的开发、验证和生产。Aviva Systems Biology为与独特物种和靶标相关的研究提供独特工具,研究领域包括转录因子、癌症、心血管、细胞生物学、DNA损伤和修复、表观遗传学、信号转导、细胞分化、干细胞生物学等等。