The gal4tye7 strain shows attenuated virulence in both A/J and C57BL/6J mouse models.

(A) A/J (i) and C57BL/6J (ii) mice were injected with either wild type (CAS8), gal4/gal4/tye7/tye7 (CAS9), or gal4/GAL4/tye7/TYE7 (CAS10) strains. A/J mice were monitored until considered moribund while C57BL/6J were monitored over a 21 day period. The revertant strain was omitted from the A/J graph since all six mice were euthanized on day 1 and would be masked by the wild type line. (B) (i) The kidney fungal load was determined 24 hours after injection for the A/J mice. Mice infected with the gal4tye7 strain had approximately ten times less C. albicans cells than the mice challenged with either the wild type or revertant strains. Another fungal load of gal4tye7 infected mice was determined upon moribundity and showed comparable levels to the mice injected with the wild type strain after 24 hours. (ii) The kidney fungal load was determined upon euthanization of C57BL/6J mice when moribundity was determined or mice survived until day 21. (C) Kidney sections of A/J infected mice were taken after euthanization and C. albicans cells were revealed with the Grocott-Gomori methenamine-silver stain. Pictures shown are from tissue infected with the gal4tye7 strain indicating hyphal formation. There was no obvious difference compared to sections taken from kidneys infected with wild type or revertant strains (data not shown).