Phagocytosis by phagocytes (such as macrophages, dendritic cells and neutrophils) is essential for a variety of biological events, including tissue remodeling and continuous clearance of dying cells, but also immunity.

Phagocytosis can be measured in vitro by measuring the engulfment of a substrate by phagocytic cells. Various substrates can be used, including red blood cells, E. coli and Zymosan particles (yeast).

Zymosan (Saccharomyces cerevisiae) is prepared from yeast cell wall and consists of proteincarbohydrate complexes. Zymosan is a commonly used pathogen in phagocytosis assays. Typically, engulfed Zymosan particles are manually counted (expressed as a phagocytosis index or engulfed particles per phagocyte). This manual counting method is quite cumbersome, time-consuming, and difficult when testing a large number of samples. 

Our Phagocytosis Assay kits (Zymosan) uses prelabeled Zymosan particles as a phagocytosis pathogen; however, it does not involve subjective manual counting of Zymosan particles inside cells. Instead external Zymosan particles are blocked before the colorimetric detection of engulfed particles.