The HMPV monoclonal antibody specifically binds to CD227 which is also known as Mucin-1 (MUC1). A major form of CD227 is expressed as a type I transmembrane glycoprotein. CD227 belongs to the epithelial mucin family whose members are heavily O-glycosylated and characterized by high molecular weight, and an amino acid composition rich in serine, threonine, proline, and glycine. CD227 is variably expressed on the surfaces of normal and malignant glandular and ductal epithelial cells, and some hematopoietic cell lineages including subsets of T cells, B cells, monocytes and dendritic cells. Soluble forms of CD227 may arise by shedding from the cell surface or by secretion of forms derived from alternative RNA splicing. The HMPV antibody binds to the core peptide of the MUC1 protein. The core protein contains a domain of 20 amino-acid tandem repeats which function as multiple epitopes for this monoclonal antibody. Incomplete glycosylation of some tumor-associated mucins may lead to variable unmasking of the multiple peptide epitopes leading to the observed differences in immunostaining intensities between cells from normal and malignant tissues. CD227 plays roles in the provision of protective barrier function, the regulation of cellular adhesion, and the transduction of multiple signal pathways.
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.