ANALYSIS OF RAT URINE PROTEINS AND ALLERGENS BY SODIUM DODECYL-SULFATE POLYACRYLAMIDE-GEL ELECTROPHORESIS AND IMMUNOBLOTTING

Background: In rats, urine has been identified as a major source of th e allergens that cause laboratory animal allergy, an important occupat ional health problem. Methods and Results: Urinary proteins and allerg ens of Wistar rats were studied by sodium dodecyl sulfate-polyacrylami de gel electrophoresis and immunoblotting. Proteins excreted by male a nd female rats during puberty were similar and of low molecular weight . In adulthood, moderate increases in diffuse staining of 26 and 21 kd occurred in female urine. In males the 1 7 kd protein increased drama tically and the 23 and 21 kd proteins moderately. The urine excretion of high-molecular-weight proteins (75 to 63 kd) increased with age in males (females not studied). Immunoblot studies with six sera showed a llergens in urine of male and female rats of all ages, three of which were present in all urine (75, 68, and 21 kd). Three allergens (I 7, 1 6, and 15 kd) in female urine may be allergenically similar to the 1 7 kd allergen in adult male urine. Adult male urine allergens were stud ied further with sera from 83 rat-hypersensitive subjects. Major aller gens were identified at 23, 21, and 17 kd, and all sera had IgE to one or more of these proteins. Twenty-seven percent had IgE to 68 and 63 kd allergens. Minor allergens were identified at 75, 51, and 44 kd. Co nclusions: Rat urine is an important source of the major allergens ass ociated with rat hypersensitivity. Age and sex markedly influence the protein and allergenic constituents of rat urine.