Trichinella spiralis: immunization of rats with an antigen fraction enriched for allergenicity.

Trichinella spiralis whole muscle larval extract was fractionated by gel filtration and anion-exchange chromatography, and the protein fractions were assayed for allergenicity by a footpad-swelling test in mice; IgE antibody levels in rats immunized with the fractions were determined by passive cutaneous anaphylaxis test in rats. By these methods, an allergenic fraction from T. spiralis was isolated. The fraction, F1-b, was shown to be monodisperse by analysis with SDS-PAGE, IEP, and isoelectric focusing, indicating that it is a single protein moiety with a molecular weight of approximately 45,000 and a pI of approximately 5.1. The Schiff-periodate test showed F1-b to be a glycoprotein. Rats immunized with F1-b had significantly fewer intestinal worms than did nonimmunized controls at 24 hr and 7 days after oral challenge with T. spiralis larvae.