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RB744 Mouse Anti-Human HLA-DP

BD OptiBuild™ RB744 Mouse Anti-Human HLA-DP

Clone B7/21 (also known as B7/21.49; B7/21 (IgG1))

Product Details
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BD OptiBuild™
HLADP; HLA-DPαβ; DPA and DPB; DPα and DPβ; DPαβ
Human (Tested in Development)
Mouse BALB/c IgG1, κ
Human NALM6 Leukemia Cells
Flow cytometry (Qualified)
0.2 mg/ml
3113, 3115
Aqueous buffered solution containing ≤0.09% sodium azide.

Preparation And Storage

Store undiluted at 4°C and protected from prolonged exposure to light. Do not freeze. The monoclonal antibody was purified from tissue culture supernatant or ascites by affinity chromatography. The antibody was conjugated to the dye under optimum conditions that minimize unconjugated dye and antibody.

Recommended Assay Procedures

BD® CompBeads can be used as surrogates to assess fluorescence spillover (compensation). When fluorochrome conjugated antibodies are bound to BD® CompBeads, they have spectral properties very similar to cells. However, for some fluorochromes there can be small differences in spectral emissions compared to cells, resulting in spillover values that differ when compared to biological controls. It is strongly recommended that when using a reagent for the first time, users compare the spillover on cells and BD® CompBeads to ensure that BD® CompBeads are appropriate for your specific cellular application.

Product Notices

  1. Please refer to for technical protocols.
  2. Please refer to to access safety data sheets (SDS).
  3. For U.S. patents that may apply, see
  4. Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.
  5. Since applications vary, each investigator should titrate the reagent to obtain optimal results.
  6. The production process underwent stringent testing and validation to assure that it generates a high-quality conjugate with consistent performance and specific binding activity. However, verification testing has not been performed on all conjugate lots.
  7. Human donor specific background has been observed in relation to the presence of anti-polyethylene glycol (PEG) antibodies, developed as a result of certain vaccines containing PEG, including some COVID-19 vaccines. We recommend use of BD Horizon Brilliant™ Stain Buffer in your experiments to help mitigate potential background. For more information visit
  8. When using high concentrations of antibody, background binding of this dye to erythroid fragments produced by ammonium chloride-based lysis, such as with BD Pharm Lyse™ Lysing Buffer (Cat. No. 555899), has been observed when the antibody conjugate was present during the lysis procedure. This may cause nonspecific staining of target cells, such as leukocytes, which have bound the resulting erythroid fragments. This background can be mitigated by any of the following: titrating the antibody conjugate to a lower concentration, fixing samples with formaldehyde, or removing erythrocytes before staining (eg, gradient centrifugation or pre-lysis with wash). This background has not been observed when cells were lysed with BD FACS™ Lysing Solution (Cat. No. 349202) after staining.
  9. For fluorochrome spectra and suitable instrument settings, please refer to our Multicolor Flow Cytometry web page at
  10. An isotype control should be used at the same concentration as the antibody of interest.
  11. Please observe the following precautions: We recommend that special precautions be taken (such as wrapping vials, tubes, or racks in aluminum foil) to protect exposure of conjugated reagents, including cells stained with those reagents, to any room illumination. Absorption of visible light can significantly affect the emission spectra and quantum yield of tandem fluorochrome conjugates.
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Antibody Details
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The B7/21 monoclonal antibody specifically recognizes HLA-DP antigens which are human Major Histocompatibility Complex (MHC) Class II antigens. HLA-DP antigens are heterodimers comprised of two different type I transmembrane glycoproteins that are noncovalently-associated. The ~34 kDa HLA-DP alpha (HLA-DPα) and ~26-28 kDa HLA-DP beta (HLA-DPβ) chains are encoded by HLA-DPA1 and HLA-DPB1 genes, respectively, that are located within the Human Leukocyte Antigen (HLA) Complex of chromosome 6. The B7/21 antibody recognizes a monomorphic determinant present on cells expressing HLA-DP1, -DP2, -DP3, -DP4, and -DP5 and does not reportedly bind to HLA-DR or HLA-DQ Class II antigens. HLA-DP is variably expressed on B cells, monocytes, macrophages, dendritic cells (DC), activated T cells, and tumor cell lines including B cell lines, myelomas, and some myeloid leukemias. HLA-DP functions in the presentation of peptides derived from extracellular antigens to CD4+ T cells.

       The original B7/21 hybridoma was derived from hybridization of mouse 5194/SXXOBU1 myeloma cells with spleen cells from BALB/c mice immunized with NALM6 human leukemia cells and secreted IgG3, κ antibody. An immunoglobulin switch-variant B7/21 hybridoma, also known as B7/21.49 or B7/21 (IgG1), was subsequently isolated that secreted lgG1 antibody with the same specificity as the original IgG3 antibody. The purified switch-variant B7/21 IgG1 antibody blocks the staining of HLA-DP-positive cells by fluorescent B7/21 IgG3 antibody.  The B7/21 IgG1 antibody is reportedly not cytotoxic in the presence of complement.

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Format Details
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The BD Horizon RealBlue™ 744 (RB744) Dye is part of the BD® family of blue dyes. It is a tandem fluorochrome with an excitation maximum (Ex Max) at 498-nm and an emission maximum (Em Max) at 746-nm as measured using an antibody-dye conjugate. Driven by BD® innovation, RB744 can be used on both spectral and conventional cytometers and is designed to be excited by the Blue laser (488-nm) with minimal excitation by the 561-nm Yellow-Green laser. For conventional instruments equipped with a Blue laser (488-nm), we recommend using an optical filter centered near 750-nm (e.g., a 750/60-nm bandpass filter).
Blue 488 nm
498 nm
746 nm
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Citations & References
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Development References (5)

  1. Anczurowski M, Hirano N. Mechanisms of HLA-DP Antigen Processing and Presentation Revisited.. Trends Immunol. 2018; 39(12):960-964. (Biology). View Reference
  2. Lennon-Duménil AM, Barbouche MR, Vedrenne J, et al. Uncoordinated HLA-D gene expression in a RFXANK-defective patient with MHC class II deficiency.. J Immunol. 2001; 166(9):5681-7. (Clone-specific: Flow cytometry). View Reference
  3. Robbins PA, Evans EL, Ding AH, Warner NL, Brodsky FM. Monoclonal antibodies that distinguish between class II antigens (HLA-DP, DQ, and DR) in 14 haplotypes.. Hum Immunol. 1987; 18(4):301-13. (Clone-specific: Blocking, ELISA, Flow cytometry, Immunoprecipitation, Radioimmunoassay). View Reference
  4. Royston I, Omary MB, Trowbridge IS. Monoclonal antibodies to a human T-cell antigen and Ia-like antigen in the characterization of lymphoid leukemia.. Transplant Proc. 1981; 13(1 Pt 2):761-6. (Immunogen: Fluorescence microscopy, Immunofluorescence, Immunoprecipitation, Radioimmunoassay). View Reference
  5. Strobl H, Bello-Fernandez C, Riedl E, et al. flt3 ligand in cooperation with transforming growth factor-beta1 potentiates in vitro development of Langerhans-type dendritic cells and allows single-cell dendritic cell cluster formation under serum-free conditions.. Blood. 1997; 90(4):1425-34. (Clone-specific: Flow cytometry). View Reference
View All (5) View Less
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Global - Refer to manufacturer's instructions for use and related User Manuals and Technical data sheets before using this products as described

Comparisons, where applicable, are made against older BD Technology, manual methods or are general performance claims.  Comparisons are not made against non-BD technologies, unless otherwise noted.

For Research Use Only. Not for use in diagnostic or therapeutic procedures.