Phycoerythrin (PE)-conjugated anti-monkey primary antibodies are fluorescent immunoreagents that combine the exceptional brightness of the R-phycoerythrin (R-PE) phycobiliprotein with the target specificity of immunoglobulins directed against non-human primate (NHP) antigens. These reagents are widely employed in flow cytometry, fluorescence-activated cell sorting (FACS), and multicolor immunophenotyping of monkey leukocyte subsets, enabling sensitive detection of cell surface markers and immunoglobulins in preclinical research, vaccine development, and translational medicine. PE-conjugated antibodies exhibit strong and stable fluorescence, high sensitivity, low background fluorescence, resistance to quenching, and are suitable for both flow cytometry and imaging applications with greater photostability than other conjugates.
The PE Fluorophore
R-Phycoerythrin is a large oligomeric phycobiliprotein isolated from red algae, with a molecular weight of approximately 240,000 daltons. The intact PE molecule is composed of three types of subunits: alpha (20,000 Da), beta (20,000 Da), and gamma (30,000 Da). The alpha subunit contains only the phycoerythrobilin (PEB) chromophore, while beta and gamma subunits contain both PEB and phycourobilin (PUB) chromophores. Variability in the absorption spectra of PEs from different species reflects differences in the PEB/PUB ratio of the subunits. The protein is soluble in aqueous environments and exhibits minimal nonspecific binding. PE and closely related B-PE are the most intensely fluorescent phycobiliproteins, with quantum efficiencies probably in excess of 90%, and their orange fluorescence is readily visible by eye in any moderately concentrated solution. The spatial arrangement of the bilin structure within the protein prevents concentration quenching and provides steric protection that enables the fluorescence to be independent of pH. PE is purified from red algae and functions as the only photosynthetic pigment-protein complex, playing a crucial role in light capture and energy conversion.
