Description: The monoclonal antibody A3 recognizes human CD148 also known as Dep-1 (density-enhanced protein tyrosine phosphatase) and ByP. CD148 is a highly glycosylated transmembrane protein, up to 250kDa, containing eight Fibronectin Type III domains in the extracellular region and one tyrosine phosphatase domain in the cytoplasmic region. Expression is found broadly including fibroblasts, epithelial cells, lymphocytes (B, T and NK cells), and myeloid cells (monocytes and granulocytes). CD148 expression can be upregulated following T cell activation. The role for CD148 has been shown to involve the dephosphorylation of proteins such as LAT and PLC-γ. One key role is the down regulation of Tcell activation. Recently CD148 has been shown to be excluded from the synapse (junction between T cells and antigen presenting cells APCs). Once the synapse disengages, CD148 can relocate and exert its effects to down-regulate the activated state. Furthermore expression of CD148 has been shown to inhibit the growth of breast cancer cells in vitro.
The monoclonal antibody A3 can neutralize the negative signal from T cell activation thereby causing activation of T cells.