The A3 monoclonal antibody specifically binds to CD148. CD148 is a receptor-type tyrosine phosphatase that belongs to the receptor class 3 subfamily of the protein-tyrosine phosphatase family. CD148 is also known as Density-enhanced phosphatase 1 (DEP-1), Human protein tyrosine phosphatase- η (HPTP-η/HPTP-eta), or Protein tyrosine phosphatase receptor type J (PTPRJ). CD148 is a highly glycosylated type I transmembrane protein that is widely expressed on different cell types including monocytes, granulocytes, dendritic cells, thymocytes, T cells, B cells, NK cells, fibroblasts, and platelets. As a protein tyrosine phosphatase with receptor function, CD148 plays a role in regulating the signaling activities of various phosphorylated cellular proteins including the PDGF Receptor, catenins and Src family kinases. In the immune system, CD148 plays a role in regulating the activities of different cell types. For example, upon T cell activation, CD148 expression is upregulated by T cells. CD148 can subsequently dephosphorylate LAT and PLC-γ signaling proteins and thereby downregulate T cell signaling responses. Immobilized A3 antibody can reportedly augment the proliferation of anti-CD3 antibody-stimulated peripheral blood T cells in culture.
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.