Radioimmunoassay of Pinellia ternata lectin

Radioimmunoassay of Pinellia ternata lectin (PTL) in rabbit serum and in root extract has been tried. The PTL was labelled with 125I using chloramine-T, and the labelled product was purified by gel chromatography. Standard suppression lines were obtained and the parallelism in serum or buffer was demonstrated. The assay time was 48 h with an intra- and inter-assay coefficient of variation of less than 12%. The PTL content in dried Pinellia ternata roots was about 28 +/- 3 mg/g. More than 40% of the i.v. injected PTL to rabbits was retained in serum at 1 h post administration.