Galleria mellonella as a model system to study Cryptococcus neoformans pathogenesis.
Evaluation of Cryptococcus neoformans virulence in a number of nonmammalian hosts suggests that C. neoformans is a nonspecific pathogen. We used the killing of Galleria mellonella (the greater wax moth) caterpillar by C. neoformans to develop an invertebrate host model system that can be used to study cryptococcal virulence, host immune responses to infection, and the effects of antifungal compounds. All varieties of C. neoformans killed G. mellonella. After injection into the insect hemocoel, C. neoformans proliferated and, despite successful phagocytosis by host hemocytes, killed caterpillars both at 37 degrees C and 30 degrees C. The rate and extent of killing depended on the cryptococcal strain and the number of fungal cells injected. The sequenced C. neoformans clinical strain H99 was the most virulent of the strains tested and killed caterpillars with inocula as low as 20 CFU/caterpillar. Several C. neoformans genes previously shown to be involved in mammalian virulence (CAP59, GPA1, RAS1, and PKA1) also played a role in G. mellonella killing. Combination antifungal therapy (amphotericin B plus flucytosine) administered before or after inoculation was more effective than monotherapy in prolonging survival and in decreasing the tissue burden of cryptococci in the hemocoel. The G. mellonella-C. neoformans pathogenicity model may be a substitute for mammalian models of infection with C. neoformans and may facilitate the in vivo study of fungal virulence and efficacy of antifungal therapies.
Duke Scholars
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Related Subject Headings
- Virulence
- Moths
- Microbiology
- Hemocytes
- Cryptococcus neoformans
- Antifungal Agents
- Animals
- 3207 Medical microbiology
- 3204 Immunology
- 3107 Microbiology
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Virulence
- Moths
- Microbiology
- Hemocytes
- Cryptococcus neoformans
- Antifungal Agents
- Animals
- 3207 Medical microbiology
- 3204 Immunology
- 3107 Microbiology