Detection of immunogens from Fraxinus spp. pollen grains

This work is aimed at characterising immunogens from Fraxinus uhdei pollen and to develop ELISA assays for their immunodetection, since it is a relevant aeroallergen. F. uhdei pollen extract contained proteins in a wide range of molecular mass from 22 to 112 kDa by SDS-PAGE; moreover, 187 fractions were detected in the 2D electrophoresis. Pollen extract was used to generate rabbit hyperimmune serum. Western blot revealed six main immunogens in a range from 40 to 21 kDa and several protein spots in 2D immunoblot. Tryptic peptides from six spots were analysed by nano-LC-ESI-MS/MS, indicating that most of proteins show homology with proteins involved in metabolism and with Ole e 11 and Fra e 2. The minimum concentration of Fraxinus spp. proteins detected by ELISA assays was 0.25 μg/mL. The detection of one 21.5 KDa protein by WB in the dust obtained from air sampling suggests the possibility to be a Fraxinus spp. protein suspended in the atmosphere. ELISA assays of the air samples detected the higher concentrations of Fraxinus spp. proteins when its airborne pollen concentrations were higher, according to the Mexican Aerobiology Network.