The MRα4-1 antibody reacts with the integrin α4 chain, which is expressed as a heterodimer with either of two β chains, β1 or β7. The α4β1 integrin (VLA-4, CD49d/CD29) is expressed on peripheral T and B lymphocytes, thymocytes, and monocytes; while the α4β7 integrin (LPAM-1) is expressed on peripheral lymphocytes. These integrins mediate a variety of cell-cell and cell-matrix interactions, recognizing the ligands CD106 (VCAM-1), MAdCAM-1, and fibronectin. It has been reported that soluble mAb MRα4-1 partially inhibits in vitro binding of VCAM-1 and mast cells to fibronectin and inhibits the enhanced degranulation of IgE-sensitized RBL-2H3 basophilic leukemia cell line induced on fibronectin-coated plates. Furthermore, plate-bound MRα4-1 antibody enhances the degranulation of IgE-sensitized RBL-2H3 cells; and subcutaneous injection of MRα4-1 mAb, along with anti-CD49e and anti-CD61 antibodies, inhibits experimentally induced passive cutaneous anaphylaxis.
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).