title: Isolation and characterization of heat-stable allergens from shrimp (Penaeus indicus).
abstract: Shrimp are among the more common causes of immediate hypersensitivity reactions to food. To characterize better the allergenic substances within shrimp, extracts from heated shrimp were systematically examined with solid-phase radioimmunoassay and sera from patients clinically sensitive to shrimp. Two heat-stable protein allergens, designated as Sa-I and Sa-II, were identified from boiled shrimp (Penaeus indicus) extracts. Sa-I was isolated by ultrafiltration, Sephadex G-25, and diethylaminoethyl-Sephacel chromatography, whereas, Sa-II, the major allergen, was purified by successive chromatography on diethylaminoethyl-Sephacel, Bio-Gel P-200, and Sepharose 4B columns. Sa-I, was homogeneous by polyacrylamide gel electrophoresis (PAGE), elicited a single band on sodium dodecyl sulfate-PAGE corresponding to a molecular weight of 8.2 kd. Sa-II was also found to be homogeneous by PAGE, crossed immunoelectrophoresis, and immunoblotting. On sodium dodecyl sulfate- PAGE, it elicited a single band with a molecular weight of 34 kd. Sa-II was found to contain 301 amino acid residues and was particularly rich in glutamate/glutamate and aspartate/asparagine. Solid-phase radioimmunoassay-inhibition studies revealed that Sa-I and Sa-II share 54% of the allergenic epitopes, suggesting that Sa-I may be a fragment of Sa-II.
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore.
authors.forename: S
authors.initials: S
authors.lastname: Naqpal
authors.forename: L
authors.initials: L
authors.lastname: Rajappa
authors.forename: D D
authors.initials: DD
authors.lastname: Metcalfe
authors.forename: P V
authors.initials: PV
authors.lastname: Rao
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology / Q000302:isolation & purification*; D000818:Animals; D000918:Antibody Specificity; D060829:Arthropod Proteins; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005512:Food Hypersensitivity / Q000209:etiology / Q000276:immunology*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007073:Immunoglobulin E / Q000378:metabolism; D008297:Male; D033561:Penaeidae / Q000276:immunology*; D011506:Proteins; D011817:Rabbits; D011863:Radioimmunoassay; D012882:Skin Tests; D014462:Ultrafiltration
chemical_list: D000485:Allergens; D060829:Arthropod Proteins; D011506:Proteins; C058449:shrimp allergens Sa; D007073:Immunoglobulin E