We aimed to determine whether T cell-specific STAT3 deletion influences the immune response to Aspergillus in the immunosuppressed context in CD4 ^{Stat3 −/−} mice. Immunosuppressed and nonimmunosuppressed CD4 ^{Stat3 −/−} mice and littermate Stat3 ^flox/flox (Stat3 ^fl/fl ) mice were infected with Aspergillus fumigatus in an aerosol chamber, and the weight, activity, appearance, and respiratory rate of the mice were monitored daily for 21 days to evaluate their survival. Aspergillus infection was confirmed by lung fungal culture counts, histology, and a galactomannan test.