Serine proteinases with gelatinolytic activity in an Aspergillus fumigatus allergenic extract.
The presence of proteolytic activity in Aspergillus fumigatus (Af) extract was analyzed in polyacrylamide gelatine containing gels at different pHs. The gelatinolytic pattern showed three major activities (180, 70, and 34 kDa bands) over a broad pH range (pH 4-8). All bands showed maximum activity at pH 8, and the activity declined at lower pH, showing no activity at pH 2. The susceptibility of the proteolytic activity to protease inhibitors confirmed that the fungal extract contained serine proteinases, and one of them, the 34 kDa band, showed a chymotrypsin-like proteinase. The immunochemical fungal extract properties were studied by western blot, and the samples were run in the presence or absence of denaturing and reducing (DTT) conditions. Two protein bands located at approximately 180 and 84 kDa showed immunoreactivity with allergenic patients' anti-Af serum, when the samples were run under denaturing and reducing conditions. In the native form an additional third immunoreactive band of about 70 kDa was found. There were no immunoreactive bands toward IgE about 34 kDa. Periodate treatment caused the decrease or disappearance of the immunoreactivity in the bands, demonstrating that epitopes recognized by serum IgE specific to Af are partially composed by carbohydrates (180 and 70 kDa bands) while others (84 kDa) are carbohydrates. Although further investigations are needed, these preliminary results suggest alkaline serine proteinases from Aspergillus fumigatus as one of the factors responsible for the fungal allergenicity.
Irañeta
Silvia G
SG
Centro de Alergia, Hospital de Clínicas, Instituto de Investigaciones Biotecnológicas, Universidad Nacional de General San Martín, Buenos Aires, Argentina.
Duschak
Vilma G
VG
Rodríguez
Sara M
SM
Alonso
Angel
A
D000946:Antigens, Fungal / Q000276:immunology*; D001229:Aspergillosis, Allergic Bronchopulmonary / Q000188:drug therapy / Q000276:immunology; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000502:physiology; D015153:Blotting, Western; D003546:Cysteine Endopeptidases / Q000276:immunology* / Q000502:physiology; D004591:Electrophoresis, Polyacrylamide Gel; D018093:Gelatinases / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012680:Sensitivity and Specificity; D012697:Serine Endopeptidases / Q000032:analysis / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000627:therapeutic use
D000946:Antigens, Fungal; D015842:Serine Proteinase Inhibitors; D012697:Serine Endopeptidases; D003546:Cysteine Endopeptidases; D018093:Gelatinases