Phagocytosis comprises a series of events, starting with the binding and recognition of particles by cell surface receptors, followed by the formation of actin-rich membrane extensions around the particle. Cell Biolabs’ CytoSelect™ 96-well Phagocytosis Assay (E. coli) uses enzyme-labeled, E. coli particles as a phagocytosis pathogen; however, it does not involve subjective manual counting of E. coli particles inside cells. Instead external particles are blocked before the colorimetric detection of engulfed E. coli particles. This format provides a quantitative, high-throughput method to accurately measure phagocytosis. The CytoSelect™ 96-well Phagocytosis Assay (E. coli) provides a robust system for screening TLR ligands, phagocytosis activators or inhibitors. Each kit provides sufficient quantities to perform 96, 48, 24 tests in a 96, 48, or 24-well plate, respectively.