The mAb I3/2.3 recognizes mouse CD45, which is also known as the leukocyte common antigen (L-CA or LCA), T200, or Lymphocyte antigen 5 (Ly-5). CD45 is a 180-240 kDa single-pass type I transmembrane glycoprotein that is encoded by Ptprc (protein tyrosine phosphatase, receptor type, C) which belongs to the protein tyrosine phosphatase (PTP) family. CD45 is variably expressed on thymocytes and other hematopoietic cells except mature erythrocytes and platelets. Different isoforms of CD45 arise from alternative splicing of variable exons 4, 5, and 6, which encode A, B, and C determinants, respectively, that encode extracellular domains of the transmembrane receptor. The differential expression of these isoforms is related to the cell's lineage as well as its state of activation and maturation. The mAb I3/2.3 reportedly recognizes all CD45 isoforms. CD45 plays key roles as a protein tyrosine-protein phosphatase in leucocyte responses including signal pathways transduced by antigen specific receptors expressed on T cells (TCRs) and B cells (BCRs).
The antibody was conjugated to BD Horizon™ BV711 which is part of the BD Horizon Brilliant™ Violet family of dyes. This dye is a tandem fluorochrome of BD Horizon BV421 with an Ex Max of 405-nm and an acceptor dye with an Em Max at 711-nm. BD Horizon BV711 can be excited by the violet laser and detected in a filter used to detect Cy™5.5 / Alexa Fluor™ 700-like dyes (eg, 712/20-nm filter). Due to the excitation and emission characteristics of the acceptor dye, there may be moderate spillover into the Alexa Fluor™ 700 and PerCP-Cy5.5 detectors. However, the spillover can be corrected through compensation as with any other dye combination.