The Protonex™ Green 500-Latex Bead Conjugate is a ready-to-use reagent designed to study phagocytosis and phagosome acidification in live cells. This conjugate combines synthetic latex beads with Protonex™ Green 500, a novel pH-sensitive fluorophore that remains non-fluorescent at neutral pH and becomes highly fluorescent upon entering acidic environments such as maturing phagosomes and phagolysosomes. As a standalone reagent, it enables users to integrate phagocytic detection into their own custom assays. The FITC-like excitation/emission properties of Protonex™ Green 500 make it compatible with a wide range of fluorescence imaging and detection systems. These conjugates can be used in combination with red fluorescent dyes like RFP, Calbryte™ 630 calcium dye, calcein red, or Cy5-labeled antibodies for multiplexed cell functional analysis. It is ideal for immunological research, drug discovery, and mechanistic studies of innate immune function, autophagy, or particle uptake.