Mapping of IgE binding regions in the major rat urinary protein, alpha(2u)-globulin, using overlapping peptides

Exposure to laboratory animals poses a hazard for development of occupation al allergy. Identification of antigenic determinants of allergenic proteins may be valuable for immunotherapeutic purposes. Overlapping peptides of th e major allergen in rat urine, Rat n 1.02, corresponding to the protein alp ha(2u)-globulin were synthesised on solid support and screened simultaneous ly to locate IgE binding linear epitopes using a simple modified ELISA proc edure. Thirty-nine peptides were synthesised, each 8 amino acids long with 4 amino acids overlaps. Sera from fifteen rat-sensitized subjects were anal yzed and as controls sera from 7 non-rat-sensitized individuals were used. In general low binding and a great individual variation between sera from r at allergic individuals were seen. Some peptides were more frequently recog nized by IgE antibodies in sera from rat allergies. These peptides were mai nly clustered towards the N-terminal and C-terminal parts of the protein. T aken together our data suggest the existence of linear IgE binding epitopes in the rat urine allergen, Rat n 1.02. However, the role of these sequence s in the allergic reaction needs further investigation.