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Pathogenesis of Cryptococcus neoformans is Associated with Quantitative Differences in Multiple Virulence Factors

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Abstract

Two isolates of Cryptococcus neoformans were previously described as being highly divergent in their level of capsule synthesis in vivo and in their virulence for mice. The highly virulent isolate (NU-2) produced more capsule than a weakly virulent isolate (184A) in vitro under tissue culture conditions and in vivo. This investigation was done to determine if there were differences between the two isolates in other factors that might also contribute to virulence. Growth rate was not a factor as NU-2 grew more slowly than 184A. Based on PCR fingerprinting the two isolates were genetically different providing an opportunity to examine differences in multiple virulence traits. Quantitative analysis revealed that NU-2 expressed significantly more melanin and mannitol than did 184A. Although the isolates expressed the same capsular chemotype, NU-2 produced an additional structure reporter group (SRG)under tissue culture conditions that was not present when grown in glucose salts/urea/basal medium (GSU).Capsular polysaccharide SRGs of 184A were unaffected by shifting the growth conditions from GSU to tissue culture conditions. Our results suggest that pathogenesis of a C. neoformans strain is dictated by the quantitative expression of the strain's combined virulence traits. Regulators of the expression of these genes may be playing key roles in virulence.

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Author notes

  1. Kent L. Buchanan

    Present address: Department of Microbiology and Immunology, Tulane University Medical Center, 1430 Tulane Avenue, New Orleans, LA, 70112, USA

Authors and Affiliations

  1. Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, USA

    Rebecca Blackstock, Kent L. Buchanan, Lydgia Jackson & Juneann W. Murphy

  2. Department of Chemistry, Georgia State University, USA

    Robert Cherniak

  3. Department of Microbiology, Duke University Medical Center, USA

    Thomas G. Mitchell

  4. Department of Internal Medicine, Yale University School of Medicine, USA

    Brian Wong & Ann Bartiss

Authors
  1. Rebecca Blackstock
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  2. Kent L. Buchanan
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  5. Brian Wong
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  7. Lydgia Jackson
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  8. Juneann W. Murphy
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Blackstock, R., Buchanan, K.L., Cherniak, R. et al. Pathogenesis of Cryptococcus neoformans is Associated with Quantitative Differences in Multiple Virulence Factors. Mycopathologia 147, 1–11 (1999). https://doi.org/10.1023/A:1007041401743

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