Biochemical, antigenic and allergenic characterization of crude extracts of Drechslera (Helminthosporium) monoceras.

In a previous study with airborne mould extracts we verified that Drechslera (Helminthosporium) monoceras presented stronger reactions than those presented by 42 other moulds isolated in São Paulo city. In the present study, we evaluated the biochemical composition and the antigenicity of crude extracts obtained from vegetative and conidial stage of D. monoceras using Czapeck broth (CB) modified and tris-HCl for extraction. The maximum values of total proteins and lipids were verified in the crude extract obtained in the 28th day of growth, and maximum values of carbohydrates were observed in the extracts of the 16th, 22nd and 26th days. The fractionated proteins by SDS-PAGE presented bands with molecular weights between 14.4 to 67 Kd; the 28th day extract showed a larger number of bands. The carbohydrates and amino acids were characterized by thin-layer chromatography. The antigenicity of the crude extracts was verified by immunodiffusion reaction in agar against rabbit hyperimmune sera. Precipitation lines were observed in all studied extracts and common antigenic molecular populations. Based on the above results, the 28th day extract was selected to verify the induction of IgE antibody responses in immunizations of Balb/c and cAF-1 mice, and titer by passive cutaneous anaphylaxis test using Wistar rats. The maximum titers obtained were 160 in cAF-1 mice and 1.280 in Balb/c mice. The results suggest that the 28th day extract contains allergenic fractions and should be chosen for future studies related to fractionation, characterization and standardization in diagnostic methods and immunotherapy.