The development of methods to measure exposure to a major rabbit allergen (Ory c 1)

Rabbits are used as laboratory animal models and are also popular domestic pets. Allergic responses to rabbit allergens have been documented in both settings, and several rabbit allergens identified. We have purified an 18 kD protein extracted from rabbit fur that was shown by N-terminal sequencing and mass spectrometry (MS) to be a lipocalin, identical to that identified as an odorant binding protein and an allergen with the formal nomenclature of Ory c 1. De novo sequencing of the MS peptide fragments gave additional primary sequence data of this protein. Polyclonal antisera were raised against the purified protein and used to develop two types of immunoassay. Ory c 1 content was measured in used rabbit bedding and household dust samples from homes keeping rabbits as pets. Atmospheric sampling was also undertaken in an animal facility undertaking rabbit experimental work. Ory c 1 levels in house dust where rabbits were kept as pets were between undetectable-41,290 ng·g^-1, and in used bedding between 370-26,740 ng·g^-1. Significantly higher house dust levels were found where rabbits spent large amounts, or all of, their time indoors. Personal air sampler levels within the animal facility were between 65-216 ng·m^-3. Low levels (0.8-2 ng·m^-3) were found in the facility's changing rooms, but undetected in the entrance lobby, office and laundry. We believe that these immunochemical assays may be used to identify activities in the occupational and domestic setting which produce higher levels of exposure to rabbit allergens, and where measures to control exposure may be warranted to reduce potential risk of allergic outcomes.