The 14.8 monoclonal antibody specifically recognizes an exon A-dependent epitope of the CD45 protein, which is found at high density on B cells and at low density on peripheral T cytotoxic/suppressor cells and a very small subset of thymocytes. Nearly all B-lineage cells, including B-cell precursors in fetal liver and adult bone marrow and Ig-secreting cells, but not hematopoietic stem cells or myeloid progenitors, have been reported to be detectable by mAb 14.8. CD45 is a member of the Protein Tyrosine Phosphatase (PTP) family: Its intracellular (COOH-terminal) region contains two PTP catalytic domains, and the extracellular region is highly variable due to alternative splicing of exons 4, 5, and 6 (designated A, B, and C, respectively), plus, differing levels of glycosylation. The CD45 isoforms detected in the mouse are cell type-, maturation-, and activation state-specific. The CD45 isoforms play complex roles in T-cell and B-cell antigen receptor signal transduction. mAb 14.8 has been reported to enhance the proliferative effect of PHA on purified spleen T cells, possibly by replacing a signal normally delivered by accessory cells, to enhance isotype switching during in vitro B-cell responses, and to inhibit antigen-induced p21 [ras] activation.
The antibody was conjugated to BD Horizon BUV615 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome with an Ex Max near 350 nm and an Em Max near 615 nm. BD Horizon Brilliant BUV615 can be excited by the ultraviolet laser (355 nm) and detected with a 610/20 filter and a 595 nm LP. Due to the excitation of the acceptor dye by the blue/yellow-green laser line, there may be significant spillover into channels detecting PE-CF594 like emissions (eg, 610/20-nm filter).