Biological techniques for studying the allergenic components of nematodes. I. detection of allergenic components in Ascaris suum extracts

1. Two allergen fractions A and B have been separated from a whole worm extract of Ascaris suum using Sephadex gel filtration. 2. Both fractions were active in inducing passive cutaneous anaphylaxis (PCA) reactions with rat anti- A. suum reaginic serum raised by immunization of rats with a whole worm extract. Only one fraction was capable of inducing a PCA reaction with rat anti- A. suum reaginic serum raised by infecting rats with A. suum eggs. 3. Studies using sequential antigen challenge techniques in the presence of disodium cromoglycate (DSCG) confirm the heterogeneous reagin response in the animals immunized with whole worm extract. This contrasts with the apparently homogeneous response when the animals were infected by A. suum eggs. 4. Further results indicate however, that one or more allergens with different antigenic determinants to those in allergen fractions A and B, are present in the crude whole worm extracts of A. suum. The additional allergen(s) stimulate a reaginic response in Ascaris-infected rats as well as in rats immunized with whole worm extract.