pHSense Eu Anti-HA, 2 x 96 wells

pHSense Eu Anti-HA is non cell permeant, and labeled with a pH sensitive europium complex. It is specifically designed to monitor the internalization of receptors and membrane proteins tagged with an HA epitope on their extracellular domain. This mouse monoclonal anti-HA antibody (IgG2b) is labeled with pHSense and raised against the twelve-amino-acid peptide sequence CYPYDVPDYASL. It recognizes the influenza virus hemagglutinin epitope (YPYDVPDYA), which has been used extensively as a general epitope tag in expression vectors. At neutral extracellular pH (≥7), its fluorescence remains minimal. Once internalized, the pHSense Eu Anti-HA encounters increasingly acidic compartments such as early and late endosomes and lysosomes, where the europium signal becomes progressively stronger. This new pH sensitive europium anti-HA is compatible with a time-resolved fluorescence (TRF) detection, effectively eliminating most fluorescence background and significantly enhancing the signal-to-background ratio. Its unique photophysical properties enable simple and robust no-wash detection of receptor-mediated endocytosis in plate-based assays with live cells.