THE SECRETED PROTEASES OF PATHOGENIC SPECIES OF ASPERGILLUS AND THEIRPOSSIBLE ROLE IN VIRULENCE

The species of Aspergillus secrete aspartic, serine and metalloproteas es. The role of secreted proteases in virulence were investigated with A. fumigatus which is the species the most frequently found in patien ts with aspergillosis. A mutant of A. fumigatus deficient in proteolyt ic activity at neutral pH in vitro, was constructed acid tested for pa thogenicity in a murine model. No difference in pathogenicity was obse rved between the wild type strain and the mutants, suggesting that the proteases secreted at neutral pH are not essential for the invasion o f the lung tissues by the fungus.