United Kingdom (UK)
Recombinant monoclonal antibody to CD123. Manufactured using AbAb’s Recombinant Platform with variable regions (i.e. specificity) from the hybridoma 7G3.
UniProt Accession Number of Target Protein: P26951
Alternative Name(s) of Target: IL3RA; IL-3RA; IL-3R-alpha; Interleukin-3 receptor subunit alpha; IL-3 receptor subunit alpha; IL-3R subunit alpha
Immunogen: The original antibody was generated by intraperitoneally immunizing BALB/c mice with 5 X lo6 COS cells transfected with the IL-3R a-chain in combination with adjuvant peptides.
Specificity: This antibody specifically binds to the IL-3R alpha-chain and completely abolishes its function. IL-3R is expressed on myeloid, lymphoid, and vascular endothelial cells, where it transduces IL-3-dependent signals leading to cell activation.
Application Notes: This antagonist antibody binds IL-3Rα and blocks IL-3 binding and IL-3-mediated functions. mAb 7G3 immunoprecipitated and recognized in western blots the IL-3R α chain expressed by transfected cells and bound to primary cells expressing IL-3Rα. The expression of IL-3Rα chain on various cells types was analysed by flow cytometry using this antibody (PMID: 8547680). It is reported that 7G3 inhibits IL-3Rα and βc dimerization (PMID: 8649415). This antibody was used in the study of neutrophils expressing IL-3 receptors which are activated by granulocyte-macrophage colony-stimulating factor or GM-CSF (PMID: 7579364). The original 7G3, mouse IgG2a antibody inhibited IL-3-mediated intracellular signaling of isolated acute myeloid leukemia (AML) CD34+ CD38− cells in vitro and reduced their survival (PMID: 19570512). Humanized version of this antibody CSL362 is available on request. CSL362, retains the ability to neutralise IL-3 and has enhanced affinity for the FcγRIIIa (CD16) on NK cells. In vitro studies have demonstrated that the increased affinity for CD16 correlates with greater antibody-dependent cell-mediated cytotoxicity (ADCC) against CD123 expressing cell lines (Busfield et al., 2012). CSL362 is being accessed for use in the treatment of myeloid leukemia (PMID: 24363400, 2524888, 26130514).
Antibody first published in:
Sun et al. Monoclonal antibody 7G3 recognizes the N-terminal domain of the human interleukin-3 (IL-3) receptor alpha-chain and functions as a specific IL-3 receptor antagonist. Blood. (1996); 87(1):83-92. PMID:8547680
Note on publication:
Describes the generation and characterization of this antibody and its role in loss of funtion of the IL-3R alpha chain.
Immunofluorescence staining of U937 cells with anti-CD123 (Ab02242) 7G3 Immunofluorescence analysis of paraformaldehyde fixed U937 cells on Shi-fix™ coverslips stained with the chimeric rabbit IgG version of 7G3 (Ab02242-23.0) at 10 µg/ml for 1h followed by Alexa Fluor® 488 secondary antibody (2 µg/ml), showing membrane staining. The nuclear stain is DAPI (blue). Panels show from left-right, top-bottom Ab02242-23.0, DAPI, merged channels and an isotype control. The isotype control was an unknown specificity antibody (Ab00178-23.0) followed by staining with Alexa Fluor® 488 secondary antibody.
Flow cytometry using the Anti-CD123 antibody 7G3 (Ab02242). Paraformaldehyde fixed U937 cells permeabilized with 0.5% Triton were stained with anti-unknown specificity antibody (Ab00178-23.0; isotype control, black line) or the rabbit IgG version of 7G3 (Ab02242-23.0, blue line) at a dilution of 1:100 for 1h at RT. After washing, the bound antibody was detected using a goat anti-rabbit IgG AlexaFluor® 488 antibody at a dilution of 1:1000 and cells analyzed using a FACSCanto flow-cytometer.