title: Direct skin test in highly sensitized guinea pigs for rapid and sensitive determination of staphylococcal enterotoxin B.
abstract: The direct skin test in highly sensitized guinea pigs was developed as a rapid and extremely sensitive assay for detection of staphylococcal enterotoxin B (SEB) in foods. This report details the experimental conditions required to elicit optimal sensitization of guinea pigs to SEB. An intense and persistent immunoglobulin E (IgE) anti-SEB response was established in strain 13 guinea pigs pretreated with cyclophosphamide followed by four sensitizing doses of 10 micrograms of SEB 1 month apart. The conditions, however, optimal for eliciting IgE responses led to a sustained failure to produce antibody of the IgG1 subclass. With the use of highly sensitized guinea pigs, one can achieve a sensitivity ranging from 0.1 to 1.0 pg of purified SEB by the direct skin test for at least 7 months after the last challenge. For analysis of SEB in food extracts, the entire assay can be accomplished within 20 min with a sensitivity of 10 to 100 pg SEB per ml of prepared food samples, and the recovery of enterotoxin from spiked food products ranged between 75 and 89% of the amount added.
mesh_terms: D001681:Biological Assay; D003520:Cyclophosphamide / Q000494:pharmacology; D004768:Enterotoxins / Q000032:analysis* / Q000276:immunology; D005506:Food Contamination; D007114:Immunization; D007073:Immunoglobulin E / Q000096:biosynthesis; D012882:Skin Tests
chemical_list: D004768:Enterotoxins; D007073:Immunoglobulin E; C031818:enterotoxin B, staphylococcal; D003520:Cyclophosphamide