IDENTIFICATION AND CHARACTERIZATION OF A 30-KD MAJOR ALLERGEN FROM PARAPENAEUS-FISSURUS

The allergenic components of the shrimp (Parapenaeus fissurus) were id entified by immunoblotting, with sera from 10 allergic patients. Six c omponents, ranging in molecular weight from about 86 to 39 kd, showed IgE-binding activity and were identified as allergens of the shrimp. T he component with a molecular weight of about 39 kd showed the highest frequency of IgE binding (70%) and was considered to be one of its ma jor allergens. Two monoclonal antibodies against this 39 kd component were generated, and their antigenic cross-reactivity with five differe nt kinds of seafood, shrimp, crab, cuttlefish, oyster, and pomfret was analyzed. Monoclonal antibody 1-6-10B reacted with the 39 kd componen t from shrimp only but monoclonal antibody 2-7-1E also reacted with th e 39 kd component from crab. By extraction with 0.5% sodium dodecylsul fate and ethanol precipitation, a highly purified shrimp 39 kd compone nt was obtained. In two-dimensional gel electrophoresis six isoforms o f this purified 39 kd component, with isoelectric point values from 5 1 to 5 6, were identified No marked difference was observed when the a mmo acid composition of this purified 39 kd allergen was compared with those of serum albumin from different animals. They all contain a hig h proportion of acidic amino acids. There was also a 62% to 83% sequen ce homology among three different pairs of peptide fragments of purifi ed 39 kd components of shrimp and crab. In conclusion, a 39 kd major a llergen from the shrimp has been identified and characterized in the p resent study. According to the suggestions of the International Union of Immunological Societies, this allergen is designated as Par f L