Involvement of MIIC-like late endosomes in B cell receptor-mediated antigen processing in murine B cells.
Involvement of MIIC-like late endosomes in B cell receptor-mediated antigen processing in murine B cells.
复制标题
DOI：
10.4049/jimmunol.162.2.1150
复制
发表时间：
1999-01
影响因子：
4.4
通讯作者：
J. Drake;T. Lewis;K. Condon;R. Mitchell;P. Webster
中科院分区：
文献类型：
--
作者：
J. Drake;T. Lewis;K. Condon;R. Mitchell;P. Webster
目前，在B细胞受体（BCR）介导的Ag加工现象中，经典内吞区室与新型内吞区室的参与是一个相当有争议的问题。在小鼠B细胞中，II类囊泡（CIIV）代表了一种新的内吞隔室，参与BCR介导的Ag加工和II类肽装载。或者，在人B细胞中，MHC II类富集区室（MIIC）代表似乎参与该过程的溶酶体（L）样内吞区室。目前，CIIV、MIIC和经典内体与L之间的关系仍有待确定。使用密度梯度离心，在小鼠B细胞中鉴定、分离和表征了在形态学和免疫学上与人MIIC相似的亚细胞区室。这些MIIC样囊泡代表了II类阳性晚期内体（LE）的群体，与CIV不同。MIIC样LE由巯基蛋白酶组织蛋白酶B唯一标记，并且沿着成熟L，似乎是这些细胞中DM分子的主要储存库。重要的是，从Ag脉冲的B细胞中分离的MIIC样LE和CIIV都含有BCR内化的Ag以及抗原肽II类复合物。
Currently, the involvement of classical vs novel endocytic compartments in the phenomenon of B cell receptor (BCR)-mediated Ag processing is a matter of considerable debate. In murine B cells, class II vesicles (CIIV) represent a novel endocytic compartment involved in BCR-mediated Ag processing and class II peptide loading. Alternatively, in human B cells, the MHC class II-enriched compartment (MIIC) represents a lysosome (L)-like endocytic compartment that appears to be involved in this process. Presently, the relationship between CIIV, MIIC, and classical endosomes and L remains to be determined. Using density gradient centrifugation, a subcellular compartment morphologically and immunologically similar to human MIIC has been identified, isolated, and characterized in murine B cells. These MIIC-like vesicles represent a population of class II-positive late endosomes (LE) and are distinct from CIIV. MIIC-like LE are uniquely marked by the thiol protease cathepsin B, and along with mature L, appear to be the major repository of DM molecules in these cells. Importantly, both MIIC-like LE and CIIV isolated from Ag-pulsed B cells contain BCR-internalized Ag as well as antigenic peptide-class II complexes.