arachin and Food-Hypersensitivity

Peanut is a rich source of plant protein which is inexpensive and abundant in nature. The peanut proteins however cause hypersensitive immunogenic responses in certain individuals. A minute amount of contamination may cause strong allergic reactions and even death. Many chemical pretreatment procedures have been developed and prescribed earlier for removal of this allergenicity. In the present article we have observed trace level Fe(III) and Cu(II) complexation of the protein fractions of peanut at pH 4.8 using different spectral methods. Consequently we studied the allergic response of Fe(III) complex of the protein fractions using competitive enzyme linked immunosorbent assay (ELISA) technique and found that there were considerable losses in allergenicity of conarachin I and arachin fractions upon complexation. Immunoassay of Cu(II) complex was avoided keeping in view the Cu toxicity in living systems. The results bring up a new strategy towards reduction of allergenicity using an inexpensive and simple methodology.

Topics: Allergens; Arachis; Enzyme-Linked Immunosorbent Assay; Ferrous Compounds; Food Hypersensitivity; Humans; Plant Proteins

Crude peanut protein fractions from raw and roasted peanuts were examined in the RAST with 10 sera from patients showing clinical peanut sensitivity. The radioactive uptake results, which were generally high, did not reveal any distinguishable pattern. Two commercially available peanut proteins, peanut lectin and phospholipase D, gave poor RAST responses. Three purified peanut proteins, alpha-arachin, conarachin I, and concanavalin A-reactive glycoprotein, all gave significant RAST results that were generally lower than those obtained with the crude extracts. The extent of RAST inhibition obtained with these materials was inversely related to their abundance in the total peanut protein. Crossed immunoelectrophoresis with extracts from raw and roasted peanut indicated the presence of 22 and 10 anodically migrating antigens, respectively. Sixteen IgE binding antigens were revealed for raw peanut and seven for roasted peanut after incubation with a mixed serum from the 10 patients in crossed radioimmunoelectrophoresis (CRIE) using 125I-labeled anti-IgE. CRIE plates treated with individual serum samples showed that all the patients had specific IgE for the major antigen peak, which has been tentatively identified as alpha-arachin. This major storage protein of peanut, which is known to be particularly heat resistant; may be of greater clinical significance than its apparently low RAST activity would seem to indicate.

Topics: Adolescent; Adult; Allergens; Antigens, Plant; Arachis; Child; Child, Preschool; Concanavalin A; Counterimmunoelectrophoresis; Electrophoresis, Polyacrylamide Gel; Female; Food Hypersensitivity; Glycoproteins; Humans; Immunoglobulin E; Lectins; Male; Phospholipase D; Plant Lectins; Plant Proteins; Radioallergosorbent Test; Sodium Dodecyl Sulfate