AffinityImmuno Products

Introduction

IL3RA encodes the alpha chain of the interleukin-3 receptor, commonly known as CD123, a cell-surface protein expressed on hematopoietic progenitors, monocytes, basophils, mast cells, plasmacytoid dendritic cells, and a subset of B cells. On its own this subunit binds IL-3 but cannot transmit a signal; only after pairing with the common beta chain shared with the GM-CSF and IL-5 receptors does the complex become competent to activate JAK2 and downstream STAT5-mediated transcription, guiding the growth and lineage commitment of blood progenitor cells. The IL3RA gene sits within a pseudoautosomal region shared by the X and Y chromosomes, alongside the related CSF2RA gene. Because CD123 is markedly upregulated on the surface of leukemic blasts in acute myeloid leukemia and related hematologic malignancies, it is widely studied as both a diagnostic marker and a candidate target for antibody-based therapies.

CD123 is markedly upregulated on leukemic blasts in acute myeloid leukemia and blastic plasmacytoid dendritic cell neoplasm, and is the validated target of the approved therapy tagraxofusp, making circulating/lysate CD123 measurement relevant to both diagnostic marker research and antibody-based AML therapy development.

Principle of the Assay

This kit uses a sandwich enzyme immunoassay format in which the microtiter plate wells are pre-coated with a capture antibody specific to Human IL-3Rα. During the assay, standards or samples are added to the appropriate wells together with a biotin-conjugated detection antibody also specific to Human IL-3Rα. Avidin conjugated to horseradish peroxidase (HRP) is then added to each well and allowed to incubate. Upon addition of TMB substrate solution, only wells containing Human IL-3Rα, the biotin-conjugated detection antibody, and the avidin-HRP conjugate produce a colorimetric signal. The enzymatic reaction is stopped by the addition of a sulphuric acid stop solution, and the resulting color is measured spectrophotometrically at 450 nm (± 10 nm). Sample concentrations are then determined by comparing each well’s optical density against the generated standard curve.