Asp t2 is a protein allergen previously identified in Aspergillus where it may comprise 20 to 40% of total fungal protein. Sensitivity to this allergen has been associated with allergic bronchopulmonary aspergillosis patients specifically. The nucleotide sequence identified for Asp f2 is found in a native 37-kDa culture filtrate protein and a 55-kDa mycelial glycoprotein. To determine if a similar nucleotide sequence is present in Altemaria, the following studies were undertaken. Fresh cultures of Altemaria, strains 96345 and 96343 were obtained from ATCC. Additional strains of Altemaria were obtained from other investigators and isolated from the wild. Cultures were grown on minimum salts and glucose in a fermentation container with constant stirring and aeration for 5 days. Rapidly expanding mycelia were removed from the culture and frozen in liquid nitrogen. RNA was isolated and CDNA was produced from 4 strains of Altemaria using commercial kits. PCR primers were designed and synthesized according to the sequence of Asp f2 found in Gene Bank (Accession number U56938). The forward primer is 5’-tga acg agg egg tcg age-3’ and the reverse primer is 5’-gca tgt ata ttc ggc aag caa tee-3’PCR procedures were carried out using CDNA from four strains of Altemaria as template. Total RNA from the strains of Altemaria was electrophoresed and a RNA blot was produced. The blot was probed with radiolabeled DNA constructed using the PCR product as a template. The electrophoretic analysis of the PCR reaction products indicated a DNA band with a molecular size very near the expected 893 nucleotide fragment for each of four strains of Altemaria tested. The probed RNA blot of four strains of Altemaria recognized complementary RNA of about 1800 base pairs. The reported full length for the Asp f2 RNA in Aspergillus is 1572. We conclude that Asp f2 is a potential crossreacting allergen between Aspergillus and Alternaria. The extent to which the protein product coded for by this nucleotide sequence is expressed in Altemaria altemata is yet to be determined.
Full conference title:
2000 American Academy of Allergy, Asthma, and Immunology Annual Meeting
- AAAAI 2000 (56th)