In Vitro Measurement of Phagocytosis and Killing of Cryptococcus neoformans by Macrophages

Macrophages are pivotal cells in immunity against a wide range of pathogens. Their most important property, as suggested by their name, is to ingest pathogens, leading to their killing, the release of inflammatory mediators and antigen processing. On the other hand, macrophages can also be exploited by microbes as a niche for survival in the host, as exemplified by Cryptococcus neoformans . This encapsulated yeast is an important cause of meningoencephalitis in immunocompromised people, particularly those with AIDS. Using culture and microscopy techniques, we present here methods that can be used to quantify phagocytosis of C. neoformans and its killing by macrophages, as well as the viability of the phagocyte after interaction.