title: Direct on air sampling filter quantification of cat allergen.
abstract: A direct on sampling filter in solution (DOSIS) method for quantification of airborne cat allergens has been developed. In this method, the allergens firmly adsorbed to a porous polytetrafluoroethylene filter are reacted with specific antibodies conjugated to alkaline phosphatase, generating a matrix-bound allergen-antibody-phosphatase complex. The treated filter is subsequently floated on a commercially available chemiluminescent phosphatase substrate solution. Aliquots of this solution are removed and analyzed luminometrically. The light intensity of the product is linearly related to the amount of allergen over a large mass range, 0-100 SQ units (1 SQ unit is about 146 pg of the allergenic protein Fel d 1). DOSIS demonstrated intra- and interassay precisions of 9% and 8% and 14% and 21% for the levels 4 and 20 SQ units per filter, respectively. The limit of quantification was estimated to 0.4 SQ units (58 pg Fel d 1) of cat allergen per filter. Application of DOSIS to analysis of cat allergen concentrations of indoor air in homes with and without cats revealed, on average, a six times higher concentration in the former (142 SQ units/m(3)) as compared to the latter (24 SQ units/m(3)). The recorded concentrations for airborne cat allergen in homes with cats are in accordance with previously reported figures. Allergen-specifically stained sampling filters revealed the particulate nature of airborne cat allergen which seemed predominantly to be carried by numerous large dust particles.
authors.affiliation: Respiratory Health and Climate Programme, National Institute for Working Life, Ekelundsvägen 16, Solna, S-11279 Stockholm, Sweden. olof.vesterberg@niwl.se
authors.forename: Leif
authors.initials: L
authors.lastname: Holmquist
authors.forename: Olof
authors.initials: O
authors.lastname: Vesterberg
mesh_terms: D000388:Air; D000393:Air Pollutants / Q000276:immunology; D016902:Air Pollution, Indoor / Q000032:analysis; D000485:Allergens / Q000032:analysis / Q000737:chemistry*; D000818:Animals; D002138:Calibration; D002415:Cats / Q000276:immunology*; D004784:Environmental Monitoring / Q000379:methods*; D005374:Filtration; D006023:Glycoproteins / Q000276:immunology; D006197:Hair / Q000378:metabolism; D012680:Sensitivity and Specificity
chemical_list: D000393:Air Pollutants; D000485:Allergens; D006023:Glycoproteins; C059296:Fel d 1 protein, Felis domesticus