Heterogeneity of allergens from, and homocytotropic antibody to, a gastro-intestinal nematode of rabbits.

More than one homocytotropic (reagin-like) antibody response in rabbits was demonstrated to a natural parasite, , a nematode which occurs only in the gastro-intestinal tract. The responses were detected by the homologous passive cutaneous anaphylaxis (PCA) reaction, three days after skin sensitization. Isoelectro-focusing of aqueous worm larval extract provided fractions in which more than one allergen was recognized. The separate allergen-homocytotropic antibody reactions were found with whole sera from different animals which had been infected by larvae of different ages, but it was not shown in this work whether this difference caused the separate antibody responses.