Trichinella spiralis: partial characterization of antigens isolated by immuno-affinity chromatography from the large-particle fraction of the muscle larvae.

A large-particle fraction, derived from muscle larvae of Trichinella spiralis by a combination of homogenization and differential centrifugation, was treated with 0.1% Triton X-100 and then centrifuged at high speed in order to obtain the soluble portion of this fraction (i.e., S3 fraction). The S3 fraction was then subjected to immuno-affinity chromatography. The antigens were eluted from the column using glycine-HCl buffer (pH 2.5). All 20 antigens were recovered from the S3 fraction in quantities that permitted physical, chemical, and biological determinations to be made on them. Antigens analyzed on SDS-PAGE ranged in molecular weight from 105,000 to 11,000 daltons Their isoelectric points were estimated with slab gel isoelectric focusing and ranged in pI from 4.0 to 9.0. The column-purified antigens were injected into mice together with an equal volume of Freund's complete adjuvant, and 2 wk later all mice were each challenged with 200 muscle larvae given orally. Immunized mice harbored 84% fewer muscle larvae at day 30 postinfection than controls, and were as immune as those mice receiving whole S3 (86% reduction). These results showed that protection-inducing antigens can be separated from the nonprotective portion of the muscle larva by immuno-affinity chromatography without loss of protection-inducing activity.