An immunochemical investigation of the allergens from Ascaris suum perienteric fluid. Cross-reactivity, molecular weight distribution and correlation with phosphorylcholine-containing components.

An extract of Ascaris suum perienteric fluid was fractionated on Sephadex G-200 and the resulting high molecular weight (approx. 600,000 daltons) and low molecular weight (approx. 16,000 daltons) fractions examined for allergenicity using human sera. Radioallergosorbent (RAST) and RAST-inhibition assays showed that the high molecular weight fraction was 15- to 40-fold more potent than the low molecular weight fraction. Crossed radio-immunoelectrophoretic analysis showed that the high molecular weight fraction contained 10 allergens in contrast to the 6 comprising the low molecular weight fraction. Polyacrylamide gel electrophoretic studies in combination with RAST indicated that two high molecular weight glycoprotein-staining components may be major allergens. A. suum cross-reacted allergenically with Toxocara canis and various life cycle stages of Nippostrongylus brasiliensis but not with Strongyloides ratti or Schistosoma mattheei. The cross-reacting allergens were predominantly of high molecular weight and the molecular weight distribution pattern obtained for A. suum, T. canis and N. brasiliensis paralleled that obtained for the distribution of the carrier of the hapten phosphorylcholine (Pc). However, it was shown that the hapten per se was not allergenic. In contrast, analysis of the allergens from N. brasiliensis using sera from rats infected with the same parasite showed that the homologous allergens were predominantly of low molecular weight (approx. 20,000 daltons) and did not contain Pc.