Cholesterol-Lecithin Slide (TsSF) and Charcoal Card (TsCC) Flocculation Tests Using an Acid Soluble Fraction of Trichinella spiralis Larvae

Abstract

Two simple sensitive flocculation tests were developed employing acid soluble T. spiralis larvae antigen absorbed onto cholesterol-lecithin crystals. Washing of the emulsion greatly increased the sensitivity of the antigen in the slide flocculation test. The addition of charcoal to the antigen emulsion permitted its use in a simple card test using serum or minute amounts of plasma collected from finger puncture. Absorption of reactive sera with a single dose of washed, packed, and essentially dry antigen-cholesterol-lecithin complex resulted in a complete removal of serologically detectable antibody indicating that the tests were based upon a true antigen-antibody system. Sensitivity of both tests was excellent. In the slide flocculation test, 64 sera from 68 patients were reactive, 2 were weakly reactive and 2 were nonreactive. All 21 sera from trichinosis patients were reactive in the charcoal card test. The tests also appear to be relatively specific. Only 3 sera from a total of 96 normal persons and patients with other diseases were reactive in the slide flocculation test; 13 sera showed weak reactions. With the charcoal card test 3 reactions were obtained with sera from a total of 64 normal individuals and patients with other diseases. The tests are especially well suited to small laboratory and field conditions because they are simple to perform and utilize antigenic emulsions which may be kept for prolonged periods without apparent loss of reactivity.