The 8A-1 monoclonal antibody specifically binds to CD148, which is also known as Protein tyrosine phosphatase receptor type J (Ptprj), Receptor-type tyrosine-protein phosphatase eta (R-PTP-eta, PTPη), or Density-enhanced phosphatase-1 (DEP-1). CD148 is a receptor-like tyrosine phosphatase that plays important roles in regulating cell growth, proliferation, differentiation, adhesion, and migration. It is expressed on a wide variety of cell types including epithelial cells, endothelial cells, and fibroblasts. For cells of hemopoietic origin, it is variably expressed on macrophages, neutrophils, dendritic cells, and on developing and mature B cells. CD148 is expressed on platelets and can regulate platelet activation. Although expressed at low levels on thymocytes and mature T cells, its expression is upregulated upon T cell receptor (TCR)-mediated stimulation and may play a role in regulating TCR signaling. CD148, along with CD45, are critical protein tyrosine phosphatases for regulating Src family kinase signaling networks in immune cells.
The antibody was conjugated to BD Horizon™ BUV661 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 with an Ex Max of 348-nm and an acceptor dye with an Em Max at 661-nm. BD Horizon Brilliant BUV661 can be excited by the ultraviolet laser (355 nm) and detected with a 670/25 filter and a 630 nm LP. Due to cross laser excitation of this dye, there may be significant spillover into channels detecting APC-like emissions (eg, 670/25-nm filter).
Due to spectral differences between labeled cells and beads, using BD™ CompBeads can result in incorrect spillover values when used with BD Horizon BUV661 reagents. Therefore, the use of BD CompBeads or BD CompBeads Plus to determine spillover values for these reagents is not recommended. Different BUV661 reagents (eg, CD4 vs. CD45) can have slightly different fluorescence spillover therefore, it may also be necessary to use clone-specific compensation controls when using these reagents.