The G28-8 monoclonal antibody specifically recognizes RP105/Bgp95, a 95-105 kDa type I membrane protein consisting of extracellular leucine-rich repeats and a short cytoplasmic domain. It is expressed on mantle zone B cells, but weakly on germinal center B cells. RP105/Bgp95 is also expressed on peripheral blood monocytes, dendritic cells, and a subset of peripheral blood lymphocytes. The extracellular domain associates with a molecule called MD-1 to form a cell surface receptor complex RP105/Bgp95/MD- 1. This receptor belongs to the family of toll-like receptors (TLR). Studies show that RP105/Bgp95/MD-1, working in concert with TLR4, controls B cell recognition and signaling of lipopolysaccharide (LPS). Reports on functional studies show that G28-8 monoclonal antibody can induce a G0 to G1 cell cycle transition and was synergistic with PMA, anti-µ, or anti-CD40 in inducing proliferation of resting B cells.
The antibody was conjugated to BD Horizon™ BB700, which is part of the BD Horizon Brilliant™ Blue family of dyes. It is a polymer-based tandem dye developed exclusively by BD Biosciences. With an excitation max of 485 nm and an emission max of 693 nm, BD Horizon BB700 can be excited by the 488 nm laser and detected in a standard PerCP-Cy™5.5 set (eg, 695/40-nm filter). This dye provides a much brighter alternative to PerCP-Cy5.5 with less cross laser excitation off the 405 nm and 355 nm lasers.