EXPOSURE OF LABORATORY-ANIMAL WORKERS TO AIRBORNE RAT AND MOUSE URINARY ALLERGENS

Background Laboratory animal workers are at high risk of developing oc cupational allergy. Little is known about the relationship between lev els of exposure and the risk of developing laboratory animal anergy. S ince laboratory animal work comprises a large number of different - of ten short lasting - tasks, it is of interest to assess which activitie s are associated with high, low or intermediate levels of allergen exp osure. Objective To develop and evaluate highly sensitive immunoassays in order to quantify rat and mouse urinary allergens in airborne dust sampled during short-lasting tasks. Methods Personal air dust samples were taken during full-shift periods as well as during specific tasks in seven laboratory animal facilities. Two sandwich enzyme immunoassa ys were developed, using rabbit antisera against rat and mouse urinary proteins. The rabbit antibodies were analysed by sodium dodecyl sulfa te-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting an d compared with IgE antibodies from sensitized laboratory animal worke rs. Results The rabbit antibodies were highly specific for rat and mou se urinary proteins and reacted with all IgE-binding allergens in eith er urinary protein preparation. The assays for rat and mouse urine wer e very sensitive, with detection limits of 0.075 ng/mL. The coefficien t of variation of the analysis was 12.9% for both assays. Animal caret akers appeared to experience the highest exposure to aeroallergens. A large variation in exposure within jobs was found, due to differences between tasks performed during the sampling day and the facility worke d at. The highest exposure levels were found during removal of contami nated bedding from the cages. However, rat and mouse allergen exposure levels during this task varied enormously between facilities, 1.1-158 ng eq/m(3) and 0.63-2000 ng eq/m(3), respectively. Conclusion Both sa ndwich immunoassays are highly specific and sensitive and are able to identify tasks of relatively short duration with high, medium and low exposure to airborne rat and mouse urinary allergens.