Host defense against the fungal pathogen Cryptococcus neoformans depends on both innate and acquired humoral and cellular immune mechanisms. Cryptococcal infection is acquired by inhalation. Therefore, the lung is the site of the initial encounter between host and microbe and the outcome of infection is decided by the local immune response. In the lung, the major host defense cell type is the alveolar macrophage. Recent studies have established that the alveolar macrophage plays a critical role in the outcome of cryptococcal infection. C. neoformans is a facultative intracellular pathogen that can replicate inside macrophages. Successful containment of cryptococcal infection involves the formation of granulomas where yeast cells can reside for long periods of time. Hence, the interaction between macrophages and C. neoformans is probably the most important determinant of the outcome of C. neoformans infection in that it governs both host defense and C. neoformans virulence and pathogenicity. In the past funding period the Casadevall laboratory made two discoveries related to C. neoformans-macrophage interactions. First, it was observed that phagocytosis triggers macrophage replication, a phenomenon that either benefits or harms the host depending on whether what ensues is one infected cell or two infected cells, respectively. Second, C. neoformans was shown to exit from infected macrophages through a mechanism that involves homotypic phagosome fusion and phagosome extrusion with survival of the host cell. This application proposes to dissect the outcome of C. neoformans phagocytosis with regards to fungal and host cell survival and damage, cell cycle progression and phagosome extrusion.
Three specific aims are proposed: 1) To determine the outcome of C. neoformans phagocytosis by FcR and/or complement receptor;2) To identify the mechanism of action and outcome of C. neoformans-induced cell cycle progression in macrophages;3) To identify the mechanism of action and outcome of macro-phagosome exocytosis in macrophages. Completion of these studies is expected to shed new light on the two fundamental cellular processes of cell replication and phagocytosis and to provide new insights on the mechanisms of C. neoformans intracellular pathogenesis. Relevance. This application seeks funds to explore how the pathogenic fungus C. neoformans interacts with the most important host defense cell in the lungs. This information is important for understanding how the fungus establishes itself in the lungs and causes disease. Furthermore, these studies will provide information that could be used to design vaccines and new therapies based on immunological reagents such as Abs.Project Narrative: This application seeks funds to explore how the pathogenic fungus interacts with the most important host defense cell in the lungs. This information is important for understanding how the fungus establishes itself in the lungs and causes disease. Furthermore, these studies will provide information that could be used to design vaccines and new therapies based on immunological reagents such as antibodies.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL059842-15
Application #
8204550
Study Section
Pathogenic Eukaryotes Study Section (PTHE)
Program Officer
Colombini-Hatch, Sandra
Project Start
1997-09-30
Project End
2013-12-31
Budget Start
2012-01-01
Budget End
2013-12-31
Support Year
15
Fiscal Year
2012
Total Cost
$373,500
Indirect Cost
$148,500
Name
Albert Einstein College of Medicine
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
110521739
City
Bronx
State
NY
Country
United States
Zip Code
10461
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DeLeon-Rodriguez, Carlos M; Casadevall, Arturo (2016) Cryptococcus neoformans: Tripping on Acid in the Phagolysosome. Front Microbiol 7:164
Prados-Rosales, Rafael; Carreño, Leandro J; Weinrick, Brian et al. (2016) The Type of Growth Medium Affects the Presence of a Mycobacterial Capsule and Is Associated With Differences in Protective Efficacy of BCG Vaccination Against Mycobacterium tuberculosis. J Infect Dis 214:426-37
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Casadevall, Arturo; Pirofski, Liise-Anne (2015) The Ebola epidemic crystallizes the potential of passive antibody therapy for infectious diseases. PLoS Pathog 11:e1004717
Robert, Vincent; Cardinali, Gianluigi; Casadevall, Arturo (2015) Distribution and impact of yeast thermal tolerance permissive for mammalian infection. BMC Biol 13:18
Achkar, Jacqueline M; Chan, John; Casadevall, Arturo (2015) B cells and antibodies in the defense against Mycobacterium tuberculosis infection. Immunol Rev 264:167-81
Coelho, Carolina; Souza, Ana Camila Oliveira; Derengowski, Lorena da Silveira et al. (2015) Macrophage mitochondrial and stress response to ingestion of Cryptococcus neoformans. J Immunol 194:2345-57
Achkar, Jacqueline M; Chan, John; Casadevall, Arturo (2015) Role of B cells and antibodies in acquired immunity against Mycobacterium tuberculosis. Cold Spring Harb Perspect Med 5:a018432
Janda, Alena; Eryilmaz, Ertan; Nakouzi, Antonio et al. (2015) Variable Region Identical IgA and IgE to Cryptococcus neoformans Capsular Polysaccharide Manifest Specificity Differences. J Biol Chem 290:12090-100

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