concanavalin-a and Aspergillosis

Intravenous infection of guinea pigs with the fungus Aspergillus fumigatus resulted in increased levels of chitinase in serum and tissues of the animals. The molecular properties of the enzyme were demonstrated to be different from those of the fungal chitinase, but also from guinea pig lysozyme and beta-N-acetylhexosaminidase. Bio-Gel P-100 gel filtration showed that in liver, spleen, heart and lung tissue of control animals there were two molecular mass forms present with apparent molecular masses of 35 kDa and 15 kDa. In brain and serum, only the 35 kDa form was detectable. Kidney showed only the 15 kDa form. Upon infection the 35 kDa form appeared in kidney and increased in the other tissues. When a less pathogenic form of the fungus was used the 35 kDa form remained absent in kidney. In contrast to human serum chitinase, the enzyme from guinea pig serum and tissues did bind to concanavalin A-Sepharose. This was the case for both molecular mass forms. The mode of cleavage of the substrate 4-methylumbelliferyl-tri-N-acetylchitotrioside (MU-[GlcNAc]3, where GlcNAc is N-acetylglucosamine) by the two forms of the enzyme was the same: both [GlcNAc]2 and [GlcNAc]3 were released. The chitinase activity levels in the control tissues showed a large variation in this order: spleen > lung, kidney > liver > heart > brain. The fact that spleen showed the highest chitinase level is in agreement with its major role as a lymphoid organ in cases of systemic infections. The relative increases upon infection were the highest for the tissues that showed low control values.

Topics: Acetylglucosamine; Animals; Aspergillosis; Aspergillus fumigatus; beta-N-Acetylhexosaminidases; Brain; Chitinases; Chromatography, Gel; Concanavalin A; Guinea Pigs; Hymecromone; Kidney; Liver; Lung; Molecular Weight; Myocardium; Oligosaccharides; Organ Specificity; Spleen; Time Factors; Trisaccharides

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.

Topics: Animals; Antibodies, Fungal; Antigens, Fungal; Aspergillosis; Aspergillus fumigatus; Concanavalin A; Disease Models, Animal; Electrophoresis, Polyacrylamide Gel; Immunoblotting; Immunocompetence; Immunosuppression Therapy; Rabbits

The water-soluble components of Aspergillus fumigatus mycelium were partially separated by fractional precipitation with ammonium sulphate. The total protein and neutral-sugar content were determined for each of the four fractions prepared and their immunological activity was examined by double diffusion. Partial chemical characterisation of these isolates by polyacrylamide-gel electrophoresis was linked to their precipitability by allowing the separated components to diffuse from the gel into an agarose medium containing an appropriate antiserum. The distribution and reactivity of antigens was monitored by two-dimensional immunoelectrophoresis with rabbit sera raised against either mycelial or culture-filtrate antigens and human sera, obtained from patients with aspergilloma and from patients with allergic bronchopulmonary aspergillosis. This technique was also used to establish that considerable variation exists in the precipitation profile seen among patient specimens. Several antigens were found to possess sugar residues that interacted with concanavalin A, when this lectin was used in an intermediate gel in two-dimensional immunoelectrophoresis.

Topics: Animals; Antigens, Fungal; Aspergillosis; Aspergillus fumigatus; Concanavalin A; Humans; Immunodiffusion; Immunoelectrophoresis; Immunoelectrophoresis, Two-Dimensional; Rabbits