Macrophages in the immune response against Cryptococcus

Abstract

Cryptococcus neoformans is a pathogenic fungus that can cause fatal infections in a range of animals including humans. C. neoformans infection starts in the lungs, initially growing either extracellulary within the alveolar space or within phagocytic macrophages, but can disseminate to the central nervous system in the absence of an adequate immune response. Macrophages, which are the first component of the cell-mediated immune response encountered by C. neoformans, are vitally important for immune defence against Cryptococcus. Uptake and destruction of C. neoformans cells by macrophages is central to the immune system’s response to cryptococcal disease. However, the fungus possesses a number of virulence factors that allow it to escape destruction and exploit the inside of the macrophage as a niche for growth and replication. This chapter will primarily outline the various interactions of C. neoformans with the host macrophage during infection but will also attempt to place these interactions within the wider scope of the evolution of cryptococcal virulence.