Immunoblot analyses of the serologic response to Aspergillus fumigatus antigens in experimental invasive aspergillosis

Abstract

The antibody response to Aspergillus fumigatus proteins was studied by the immunoblot technique in a rabbit model of invasive aspergillosis. Components of an A. fumigatus mycelial homogenate homogenate unbound by concanavalin A-Sepharose 4B chromatography were fractionated using SDS-PAGE and transferred to nitrocellulose papers. The protein fraction was probed with serial sera obtained from immunosuppressed or nonimmunosuppressed rabbits inoculated intravenously with saline or graded inocula of A. fumigatus conidia. Seroconversion against antigens of 41, 54, and 71 kDa was demonstrated in 7 (50%), 3 (21%), and 3 (21%) of 14 infected animals that survived greater than or equal to 10 days. Antibodies against the three antigens were detected in 4 (12.5%), 19 (59%), and 14 (44%) of 32 rabbits before immunosuppression or infection. Two-dimensional immunoblotting revealed that the 41-, 54-, and 71-kDa antigens were derived in denaturing conditions from a single component resolved in nondenaturing polyacrylamide gel electrophoresis.