Differences in cell morphometry, cell wall topography and gp70 expression correlate with the virulence of Sporothrix brasiliensis clinical isolates

PLoS One. 2013 Oct 7;8(10):e75656. doi: 10.1371/journal.pone.0075656. eCollection 2013.

Abstract

Sporotrichosis is a chronic infectious disease affecting both humans and animals. For many years, this subcutaneous mycosis had been attributed to a single etiological agent; however, it is now known that this taxon consists of a complex of at least four pathogenic species, including Sporothrix schenckii and Sporothrix brasiliensis. Gp70 was previously shown to be an important antigen and adhesin expressed on the fungal cell surface and may have a key role in immunomodulation and host response. The aim of this work was to study the virulence, morphometry, cell surface topology and gp70 expression of clinical isolates of S. brasiliensis compared with two reference strains of S. schenckii. Several clinical isolates related to severe human cases or associated with the Brazilian zoonotic outbreak of sporotrichosis were genotyped and clustered as S. brasiliensis. Interestingly, in a murine subcutaneous model of sporotrichosis, these isolates showed a higher virulence profile compared with S. schenckii. A single S. brasiliensis isolate from an HIV-positive patient not only showed lower virulence but also presented differences in cell morphometry, cell wall topography and abundant gp70 expression compared with the virulent isolates. In contrast, the highly virulent S. brasiliensis isolates showed reduced levels of cell wall gp70. These observations were confirmed by the topographical location of the gp70 antigen using immunoelectromicroscopy in both species. In addition, the gp70 molecule was sequenced and identified using mass spectrometry, and the sequenced peptides were aligned into predicted proteins using Blastp with the S. schenckii and S. brasiliensis genomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Shape / physiology*
  • Cell Wall / metabolism*
  • Genotype
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Humans
  • Mice
  • Mice, Inbred BALB C
  • Sporothrix / isolation & purification*
  • Sporothrix / metabolism
  • Sporothrix / pathogenicity*
  • Sporotrichosis / genetics
  • Sporotrichosis / metabolism
  • Sporotrichosis / microbiology
  • Virulence

Substances

  • Glycoproteins

Grant support

LMLB is a research fellow of Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). This work was supported by grants from Fundação de Amparo a Pesquisa do Estado do Rio de Janeiro (Faperj), CNPq and PRONEX. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.