The G7-26 monoclonal antibody specifically recognizes the constant region of human Immunoglobulin E (IgE). It does not crossreact with other immunoglobulin heavy chain isotypes. IgE exists in a transmembrane form that is expressed by B lymphocytes and serves as an antigen receptor. Soluble IgE is produced and secreted by activated B cells and plasma cells. IgE may bind through its constant region to cell surface receptors, such as the high-affinity (FcεRI) or low-affinity (FcεRII/CD23) receptors for IgE. FcεRI is expressed on mast cells, basophils, and at lower levels, on dendritic cells and monocytes. FcεRII/CD23 is expressed by B cells and by some other cell types including T cells, monocytes, eosinophils, neutrophils, follicular dendritic cells, and Langerhans cells. Crosslinking of Fc receptor-bound IgE antibodies by multivalent antigens or allergens can induce phagocytosis or the cellular release of inflammatory mediators. Although IgE can provide immune protection against pathogenic parasites, it may also play a central role in a variety of allergic disorders.
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.