HLA-DRA ELISA Kit (Human)

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.

Aviva Systems Biology HLA-DRA ELISA Kit (Human) (OKCA00694) is based on standard sandwich enzyme-linked immuno-sorbent assay technology. An antibody specific for HLA-DRA has been pre-coated onto a 96-well plate (12 x 8 Well Strips) . Standards or test samples are added to the wells, incubated and removed. A biotinylated detector antibody specific for HLA-DRA is added, incubated and followed by washing. Avidin-Peroxidase Conjugate is then added, incubated and unbound conjugate is washed away. An enzymatic reaction is produced through the addition of TMB substrate which is catalyzed by HRP generating a blue color product that changes to yellow after adding acidic stop solution. The density of yellow coloration read by absorbance at 450 nm and is quantitatively proportional to the amount of sample HLA-DRA captured in the well.

Reconstitution & Storage Instructions Western Blotting/Immunoblotting (WB/IB) Protocol Immunohistochemistry (IHC) Protocol Immunocytochemistry (ICC) Protocol Enzyme-Linked ImmunoSorbent Assay (ELISA) Protocol Blocking Peptide Competition Protocol (BPCP) Immunoprecipitation (IP) Protocol Antibody Array (AA) Protocol Reconstitution & Storage Instructions Reconstitution & Storage Instructions Western Blotting/Immunoblotting (WB/IB) Protocol Western Blotting/Immunoblotting (WB/IB) Protocol Immunohistochemistry (IHC) Protocol Immunohistochemistry (IHC) Protocol Immunocytochemistry (ICC) Protocol Immunocytochemistry (ICC) Protocol Enzyme-Linked ImmunoSorbent Assay (ELISA) Protocol Enzyme-Linked ImmunoSorbent Assay (ELISA) Protocol Blocking Peptide Competition Protocol (BPCP) Blocking Peptide Competition Protocol (BPCP) Immunoprecipitation (IP) Protocol Immunoprecipitation (IP) Protocol Antibody Array (AA) Protocol Antibody Array (AA) Protocol

Matrix Recovery range (%) Average (%) Serum (n=5) 92 88-96 EDTA Plasma (n=4) 96 90-101 Matrix Recovery range (%) Average (%) Matrix Recovery range (%) Average (%) Serum (n=5) 92 88-96 Serum (n=5) 92 88-96 EDTA Plasma (n=4) 96 90-101 EDTA Plasma (n=4) 96 90-101