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HLA-DRB (MHC II) Antibody - With BSA and Azide

Mouse Monoclonal Antibody [Clone L243 ]

Product Information
  • Applications Legend:
  • WB=Western Blot
  • IHC=Immunohistochemistry
  • IHC-P=Immunohistochemistry (Paraffin-embedded Sections)
  • IHC-F=Immunohistochemistry (Frozen Sections)
  • IF=Immunofluorescence
  • FC=Flow Cytopmetry
  • IC=Immunochemistry
  • ICC=Immunocytochemistry
  • IP=Immunoprecipitation
  • DB=Dot Blot
  • CHIP=Chromatin Immunoprecipitation
  • FA=Fluorescence Assay
  • IEM=Immunoelectronmicroscopy
  • EIA=Enzyme Immunoassay
Primary Accession P01911
Other Accession 3123, 534322
Reactivity Human, Monkey, Baboon, Squirrel, Chimpanzee, Dog
Host Mouse
Clonality Monoclonal
Isotype Mouse / IgG2a, kappa
Clone Names L243
Calculated MW ~28kDa (beta chain)
Additional Information
Gene ID 3123
Other Names HLA class II histocompatibility antigen, DRB1-15 beta chain, DW2.2/DR2.2, MHC class II antigen DRB1*15, HLA-DRB1, HLA-DRB2
StorageStore at 2 to 8°C.Antibody is stable for 24 months.
Precautions HLA-DRB (MHC II) Antibody - With BSA and Azide is for research use only and not for use in diagnostic or therapeutic procedures.
Protein Information
Synonyms HLA-DRB2
Function 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.
Cellular Location Cell membrane; Single-pass type I membrane protein Endoplasmic reticulum membrane; Single-pass type I membrane protein Golgi apparatus, trans-Golgi network membrane; Single-pass type I membrane protein. Endosome membrane; Single-pass type I membrane protein. Lysosome membrane; Single-pass type I membrane protein. Late endosome membrane; Single-pass type I membrane protein. Note=The MHC class II complex transits through a number of intracellular compartments in the endocytic pathway until it reaches the cell membrane for antigen presentation
Research Areas
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This MAb reacts with the HLA-DRB1 antigen, a member of MHC class II molecules. It does not cross react with HLA-DP and HLA-DQ. It binds a conformational epitope on HLA-DR, which depends on the correct folding of the Ī �Ī � heterodimer. This MAb has been reported to block mixed lymphocyte reactions. The L243 antibody recognizes a different epitope than the LN3 monoclonal antibody, and these antibodies do not cross-block binding to each other's respective epitopes. HLA-DR is a heterodimeric cell surface glycoprotein comprised of a 36kD alpha (heavy) chain and a 28kD beta (light) chain. It is expressed on B-cells, activated T-cells, monocytes/macrophages, dendritic cells and other non-professional APCs. In conjunction with the CD3/TCR complex and CD4 molecules, HLA-DR is critical for efficient peptide presentation to CD4+ T cells. It is an excellent histiocytic marker in paraffin sections producing intense staining. True histiocytic neoplasms are similarly positive. HLA-DR antigens also occur on a variety of epithelial cells and their corresponding neoplastic counterparts.


Horejsi, V., et al. 1986. Characterization of seven new monoclonal antibodies against human DR, DR + DP and DQ1 + DQ3 antigens. Tissue Antigens 28: 288-297. | Brodsky FM. A matrix approach to human class II histocompatibility antigens: reactions of four monoclonal antibodies with the products of nine haplotypes. Immunogenetics. 1984;19(3):179-94 | Engleman EG, Warnke R, Fox RI, Dilley J, Benike CJ, Levy R. Studies of a human T lymphocyte antigen recognized by a monoclonal antibody. Proc Natl Acad Sci U S A. 1981;78(3):1791-5

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$ 124.00
$ 324.00
$ 454.00
Cat# AH11451
(40 western blots)
Availability: 2-3 days
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