HLA-DR Antibody (LN-3) [mFluor Violet 450 SE]

mFluor(TM) is a trademark of AAT Bioquest, Inc. This conjugate is made on demand. Actual recovery may vary from the stated volume of this product. The volume will be greater than or equal to the unit size stated on the datasheet.

Human Leukocyte Antigen -DR isotype (HLA-DR) is a major histocompatibility complex (MHC) class II molecule expressed by antigen presenting cells (APCs) that plays a significant role in immune response (1). Class II molecules also include isoforms HLA-DP and -DQ (1,2). These type I membrane glycoproteins on APCs present peptides to helper T cells and T cell receptors on CD4+ cells (1). In humans, the genes encoding class II MHC proteins are located on chromosome 6p21, where HLA-DR is typically the most highly expressed, followed by HLA-DQ and then HLA-DP (3). Structurally, HLA-DR molecules are heterodimers consisting of an alpha chain subunit with an approximate theoretical molecular weight of 34 kDa and one of many approximately 30 kDa beta subunits (1-3). The alpha and beta genes are considered highly polymorphic with duplication resulting in nine DRB (beta subunit of HLA-DR) genes (DRB1-DRB9); though only DRB1, DRB3, DRB4, and DRB5 are considered functional (2,3). On the other hand, the alpha subunit is encoded by a single DRA gene (2,3). Studies focusing on the structural and biochemical properties of peptides that bind to HLA-DR molecules have helped contribute to subunit vaccine design and development (3).

Given the role in adaptive immunity, HLA-DR allele polymorphisms, gene misexpression, and dysfunction has been implicated in many diseases ranging from autoimmune disorders to cancer (2). HLA-DR is also a classical biomarker for disease, including sepsis where reduced expression of HLA-DR molecules on monocytes, as measured by flow cytometry, indicates diagnosis and prognosis (4,5). Immunosuppression observed with sepsis results in decreased surface expression of HLA-DR and concurrent increase in expression of programmed death 1 (PD-1), cytotoxic T-lymphocyte antigen 4 (CTLA-4), and B and T lymphocyte attenuator (BTLA) (4). This altered expression results in poor T cell response and apoptosis, along with reduced interferon-gamma (IFN-gamma) production and increased pro-inflammatory cytokine release (4). Furthermore, the decrease in HLA-DR expression is also correlated with the decrease in CD14lowCD16+ inflammatory monocytes (5). Interestingly, COVID-19 patients also exhibit a reduction in HLA-DR that correlates with disease severity and immunosuppression (5).

References

1. Andersson G. (1998). Evolution of the human HLA-DR region. Frontiers in bioscience : a journal and virtual library. https://doi.org/10.2741/a317

2. Shiina, T., Hosomichi, K., Inoko, H., & Kulski, J. K. (2009). The HLA genomic loci map: expression, interaction, diversity and disease. Journal of human genetics. https://doi.org/10.1038/jhg.2008.5

3. Stern, L. J., & Calvo-Calle, J. M. (2009). HLA-DR: molecular insights and vaccine design. Current pharmaceutical design. https://doi.org/10.2174/138161209789105171

4. Zhuang, Y., Peng, H., Chen, Y., Zhou, S., & Chen, Y. (2017). Dynamic monitoring of monocyte HLA-DR expression for the diagnosis, prognosis, and prediction of sepsis. Frontiers in bioscience (Landmark edition). https://doi.org/10.2741/4547

5. Benlyamani, I., Venet, F., Coudereau, R., Gossez, M., & Monneret, G. (2020). Monocyte HLA-DR Measurement by Flow Cytometry in COVID-19 Patients: An Interim Review. Cytometry. Part A : the journal of the International Society for Analytical Cytology. https://doi.org/10.1002/cyto.a.24249

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Primary Antibodies are guaranteed for 1 year from date of receipt.

Array NBP2-47670MFV450

• HLA-DR Antibodies