Development of a Sandwich ELISA to Measure Exposure to Occupational Cow Hair Allergens

Background: Cow hair and dander are important inducers of
occupational allergies in cattle-exposed farmers. To estimate
allergen exposure in farming environments, a sensitive enzyme
immunoassay was developed to measure cow hair allergens. Methods: A
sandwich ELISA was developed using polyclonal rabbit antibodies
against a mixture of hair extracts from different cattle breeds. To
assess the specificity of the assay, extracts from other mammalian
epithelia, mites, molds and grains were tested. To validate the new
assay, cow hair allergens were measured in passive airborne dust
samples from the stables and homes of farmers. Dust was collected
with electrostatic dust fall collectors (EDCs). Results: The
sandwich ELISA was found to be very sensitive (detection limit: 0.1
ng/ml) and highly reproducible, demonstrating intra-and interassay
coefficients of variation of 4 and 10%, respectively. The assay
showed no reactivity with mites, molds and grains, but some
cross-reactivity with other mammalian epithelia, with the strongest
reaction with goat. Using EDCs for dust sampling, high
concentrations of bovine allergens were measured in cow stables
(4,760-559,400 mu g/m(2)). In addition, bovine allergens were
detected in all areas of cattle farmer dwellings. A large variation
was found between individual samples (0.3-900 mu g/m(2)) and
significantly higher values were discovered in changing rooms.
Conclusion: The ELISA developed for the detection of cow hair
proteins is a useful tool for allergen quantification in
occupational and home environments. Based on its low detection
limit, this test is sensitive enough to detect allergens in passive
airborne dust. Copyright (C) 2011 S. Karger AG, Basel