Anti-Human HLA-DR (MHC Class II) – Purified

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This purified antibody is formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.4, 1% BSA and 0.09% sodium azide as a preservative.

This purified antibody is stable when stored at 2-8°C. Do not freeze.

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Clone L243 recognizes a conformational epitope on the human MHC class II molecule HLA-DRα, which depends on the correct folding of the αβ heterodimer1. It does not cross-react with HLA-DP or HLA-DQ.

HLA-DR antibody, clone L243, recognizes the major histocompatibility complex (MHC) class II molecule Human Leukocyte Antigen - DR isotype (HLA-DR). MHC class II is constitutively expressed on human professional antigen-presenting cells (APCs), including macrophages/monocytes, dendritic cells (DCs), and B cells, and is induced on T cells upon activation². HLA-DR consists of two transmembrane proteins, a 35 kDa α (heavy) chain and 29 kDa β (light) chain³ encoded by the HLA-DRA and HLA-DRB1, HLA-DRB3, HLA-DRB4, and HLA-DRB5 genes, respectively, located in the HLA complex of chromosome 6. The N-terminal α1 and β1 domains form the antigen-binding groove, which binds 13-25 aa peptides derived from exogenous antigens⁴. On APCs, MHC class II plays a critical role in the adaptive immune response by presenting phagocytosed antigens to helper CD4 T cells. The T cell receptor (TCR)/CD3 complex of CD4 T cells interacts with peptide-MHC class II, which induces CD4 T cell activation leading to the coordination and regulation of other effector cells. CD4 molecules also bind to MHC class II, which helps augment TCR signaling⁵. It has also been demonstrated that MHC class II express on activated T cells are capable of antigen presentation⁶ and can transduce signals into T cells, enhancing T cell proliferation and activity⁷. HLA-DR expression is a marker of T cell activation and correlates with disease activity in patients with autoimmune disease⁸ and rapid progression in HIV infection⁹. Specific alleles of HLA-DR are associated with autoimmune diseases, including rheumatoid arthritis¹⁰.

HLA-DR is expressed on antigen-presenting cells, including macrophages, monocytes, DCs, and B cells, and activated T cells.

CD3/TCR, CD4

Peptide presentation

1. Moro M, Cecconi V, Martinoli C, et al. (2005) BMC Immunol. 6:24
2. Holling TM, et al. (2004) Hum Immunol. 65(4):282-90
3. Mitaksov V, (2006) J Biol Chem. 281(15):10618-25
4. Wieczorek M, et al. (2017) Front Immunol. 8:292
5. Artyomov MN, et al. (2010) Proc Natl Acad Sci USA. 107(39):16916-16921
6. Barnaba V, et al. (1994) Eur J Immunol. 24(1):71-5
7. Di Rosa F, et al. (1993) Hum Immunol. 38(4):251-60
8. Viallard JF, et al. (2001) Clin Exp Immunol. 125(3):485-491
9. Langford SE, Ananworanich J, Cooper DA. (2007) AIDS Res Ther. 2007;4:11
10. Gough SC, Simmonds MJ. (2007) Curr Genomics. 8(7):453-465