Description

Description: 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.

Additional Text

Gene Name

HLA-DQB1

Uniprot ID

P01920

Purification

Protein G purified

Gene ID

3119

Antibody Clonality

Polyclonal

Specificity

CELIAC1 antibody; DQ beta 1 chain antibody; DQB1_HUMAN antibody; HLA class II histocompatibility antigen antibody; HLA class II histocompatibility antigen; DQ beta 1 chain antibody; HLA class II histocompatibility antigen; DQ beta 2 chain antibody; HLA DQB antibody; HLA DQB1 antibody; HLA-DQB1 antibody; HLA-DQB2 antibody; IDDM1 antibody; Lymphocyte antigen antibody; Major histocompatibility complex class II beta antibody; Major histocompatibility complex; class II; DQ beta 1 antibody; MHC class II antigen DQB1 antibody; MHC class II antigen HLA DQ beta 1 antibody; MHC class II DQ beta chain antibody; MHC class II HLA DQ beta glycoprotein antibody; MHC class2 antigen antibody; MHC DQ beta antibody; OTTHUMP00000029167 antibody; OTTHUMP00000178569 antibody; OTTHUMP00000178570 antibody; OTTHUMP00000178571 antibody