CD98 is a disulfide-linked heterodimer composed of a ~80-85 kDa, type II membrane glycoprotein heavy chain, (CD98hc), and ~40-45 kDa light chain. The UM7F8 monoclonal antibody specifically recognizes CD98hc, which is also known as 4F2 heavy chain antigen (4F2hc). CD98 is broadly expressed on hematopoietic cells, including peripheral blood lymphocytes, monocytes and granulocytes (low), as well as non-hematopoietic cells, eg, intestinal epithelial cells. CD98 expression is upregulated on activated and proliferating cells. CD98hc is encoded by the SLC3A2 [solute carrier family 3 (amino acid transporter heavy chain), member 2] gene. CD98 reportedly functions in transmembrane amino acid transport and in the regulation of integrin signaling which are involved in the regulation of cellular activation, proliferation, and survival. The UM7F8 antibody is reportedly a functional antibody that can costimulate T cell proliferative responses.
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.