Measurement of airborne proteins involved in Bakers' asthma

We have developed a competitive inhibition immunoassay to measure airborne flour, using purified polyclonal rabbit IgG antibodies to cereal flour antigens. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed different flours contained proteins of molecular weight similar to those present in air sample eluates. Western blotting demonstrated that the purified rabbit IgG antibodies bound to proteins whose molecular weights are similar to human allergens. Air sample eluates obtained from a large bakery had slopes of inhibition parallel to cereal flour when compared in the immuno-inhibition assay. The assay identified airborne proteins from several flours with a detection limit of 1 microgram ml-1. Using this immunoassay we have shown that a wide range of airborne flour concentrations occur in flour mills and a smaller range bakeries. This assay which allows measurement of the concentration of flour aeroallergen in the workplace will be valuable both in epidemiological studies and in examining the effectiveness of interventions to reduce the concentration of flour in the air.