![]() Macrophages alone seem unable to clear infection and an adaptive immune response leading to a self-resolving granuloma is required 7. neoformans is thought to occur through the lungs where, in the immunocompetent, the first immune cells to encounter cryptococci will most likely be alveolar macrophages. However, there are a number of unifying features in susceptibility to cryptococcal disease, notably a failure in a pro-inflammatory immune response to primary infection 4, 5, 6. ![]() Cryptococcal meningitis is also found associated with a large variety of other immune deficient states, including in patients on immunosuppressive therapies 2, 3, those with hematological malignancy and other more oblique disorders 4. Thus, high-content imaging of cryptococcal infection in vivo demonstrates how very early interactions between macrophages and cryptococci are critical in the outcome of cryptococcosis.Ĭryptococcus neoformans is a fungal pathogen of humans that causes life-threatening cryptococcal meningitis in immunocompromised patients, in particular those with advanced AIDS 1. We show that macrophages preferentially phagocytose cryptococci with smaller polysaccharide capsules and that capsule size is greatly increased over twenty-four hours of infection, a change that is sufficient to severely limit further phagocytosis. We find phagocytosis is restrained very early in infection and that increases in cryptococcal number are driven by intracellular proliferation. neoformans, a failure of macrophage response is not the limiting defect in fatal infections. Using this approach we demonstrate that, while macrophages are critical for control of C. Here we describe a high-content imaging method in a zebrafish model of cryptococcosis that permits the detailed analysis of macrophage interactions with C. Two current limitations are: 1) The difficulties in interpreting studies using isolated macrophages in the context of the progression of infection, and 2) The use of high resolution imaging in understanding immune cell behavior during animal infection. Many questions remain regarding the function of macrophages in normal clearance of cryptococcal infection and the defects present in uncontrolled cryptococcosis. K151).Cryptococcus neoformans is a significant fungal pathogen of immunocompromised patients. ![]() Note: Production of capsular material may be increased by cultivation in a 1% peptone solution (Peptone Broth, Cat. Further dilution with water is not recommended. Using reduced examine the smear microscopically (100X) for the presence of encapsulated cells as indicated by clear zones surrounding the cells. The preparation should be brownish, not black. Place a cover slip over the smear and press gently. Mix the specimen with a small drop of India on a clean glass slide. This product is used in conjunction with other biochemical and serological tests to identify cultures of isolated organisms. Specimen Collection: Specimens should be collected in sterile containers or with sterile swabs and transported immediately to the laboratory. Organisms that possess a polysaccharide capsule exhibit a halo around the cell against the black background created by the India. Hardy Diagnostics India Ink is recommended for use in the identification of Cryptococcus neoformans.Ĭryptococcus neoformans, because of its large polysaccharide capsule, can be visualized by the India stain.
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