The pathobiology of Paracoccidioides brasiliensis.
Paracoccidioides brasiliensis causes one of the most prevalent systemic mycoses in Latin America--paracoccidioidomycosis. It is a dimorphic fungus that undergoes a complex transformation in vivo, with mycelia in the environment producing conidia, which probably act as infectious propagules upon inhalation into the lungs, where they transform to the pathogenic yeast form. This transition is readily induced in vitro by temperature changes, resulting in modulation of the composition of the cell wall. Notably, the polymer linkages change from beta-glucan to alpha-glucan, possibly to avoid beta-glucan triggering the inflammatory response. Mammalian oestrogens inhibit this transition, giving rise to a higher incidence of disease in males. Furthermore, the susceptibility of individuals to paracoccidioidomycosis has a genetic basis, which results in a depressed cellular immune response in susceptible patients; resistance is conferred by cytokine-stimulated granuloma formation and nitric oxide production. The latency period and persistence of the disease and the apparent lack of efficacy of humoral immunity are consistent with P. brasiliensis existing as a facultative intracellular pathogen.
Borges-Walmsley
M Ines
MI
Division of Infection and Immunity, Robertson Building, Institute of Biomedical and Life Sciences, University of Glasgow, G11 6NU., Glasgow, UK.
Chen
Daliang
D
Shu
Xinhua
X
Walmsley
Adrian R
AR
D000595:Amino Acid Sequence; D000818:Animals; D002473:Cell Wall / Q000187:drug effects / Q000201:enzymology; D004195:Disease Models, Animal; D004967:Estrogens / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D010228:Paracoccidioides / Q000472:pathogenicity* / Q000502:physiology; D010229:Paracoccidioidomycosis / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D016415:Sequence Alignment; D015398:Signal Transduction; D013696:Temperature
D004967:Estrogens; D005656:Fungal Proteins