An Investigation of the Allergens of Ascaris lumbricoides Using a Radioallergosorbent Test (Rast) and Sera of Naturally Infected Humans: Comparison With an Allergen for Mice Identified by a Passive Cutaneous Anaphylaxis Test

Abstract

The identification of those components of A. lumbricoides (var. suum) body fluid (ABF) which are Ig[immunoglobulin]E-inducing antigens (allergens) depends on the type of assay used. The radioallergosorbent test and sera from humans naturally infected with A. lumbricoides revealed that ABF contains a range of allergens with a variety of isoelectric points and MW. Some cross-reactions were demonstrated between the allergens of A. lumbricoides and Toxocara canis. When a passive cutaneous anaphylaxis assay was used with sera from mice sensitized by nasal inhalation of ABF plus Bordetella pertussis vaccine, only 1 relatively pure fraction of ABF was involved. This consisted of some of the largest protein molecules in ABF: it had a MW of approximately 360,000 (subunits 140,000 and 220,000), an isoelectric region of 8.0-8.4, and was clearly very different from the allergens isolated from ABF by other workers. ABF and its fractions need to be freshly prepared and kept in the presence of reducing agents to avoid rapid deterioration and irreproducibility of some results. The relatively pure allergen fraction of ABF, isolated after identification by the passive cutaneous anaphylaxis assay and tested in mice, was T [thymus-derived] cell-stimulating but was non-mitogenic. Access to the circulation after intranasal administration appeared highly restricted.