Relationship between Candida albicans epidermolytic proteinase activity and virulence in mice.

Five strains of Candida albicans with previously characterized epidermolytic acid proteinase activity were evaluated for virulence following intravenous (i.v.) injection in mice. Increased proteinase activity was associated with increased virulence in female, NYLAR mice receiving 10(6) cells i.v. Mean mortality times (1.25, 2.0, 2.0, 4.25 and 19.6 days, in groups of 20 mice for each of the five strains) correlated directly with degree of proteinase activity. Three of the strains were selected for additional in vivo study and the association between increased proteinase activity and increased mortality rates was confirmed in dose-response studies in two additional strains of mice. The mean survival times appeared to be independent of fungal growth rate in vitro. These results support the positive correlation between proteinase activity and virulence.