Jacquelyn Beaudrie

Cryptococcus neoformans is an opportunistic fungal pathogen that is the causative agent of cryptococcal meningitis in immunocompromised individuals. A primary infection is established in the lungs via the inhalation of desiccated yeast cells or spores. If an individual becomes immunosuppressed, then systemic dissemination will occur, with a predilection to the central nervous system. Some studies on macrophages have suggested that M2 macrophages phagocytose, but do not kill, C. neoformans- allowing systemic dissemination of C. neoformans from the lungs. However, this phenomenon has yet to be fully studied via live cell imaging. Our experiments show that C. neoformans are phagocytosed quickly by M1, round macrophages. Spindle-like M2 macrophages endocytosed more C. neoformans but did not kill, allowing these C. neoformans to grow within the macrophage. In conclusion, M1 macrophages are able to quickly phagocytose C. neoformans while M2 macrophages are not. Therefore we hypothesize that, M1 macrophages phagocytose Cryptococcus neoformans within the first 24 hours of infection while M2 macrophages endocytose C. neoformans and allow continued growth within the macrophage. Future experiments include differentiating M1 from M2 macrophages to analyze the two separate populations in a macrophage killing assay and to determine the difference between the subpopulation responses.