DETERMINATION OF RICIN IN ENVIRONMENTAL SAMPLES USING BIOASSAY

A bioassay of ricin toxicity in environmental samples using real-time cell index monitoring is proposed. The halfmaximal inhibitory concentration (IC50) of ricin was estimated at 6,7 ng/ml for human hepatoma HepaRG cells proliferation. The antibodies to A- and B-subunits in HepaRG cell media lead to cytoprotective and antiapoptotic effects against the cytotoxicity of ricin. The antibodies neutralised activation of JNK kinase (phosphorylated at Thr183/Tyr185) and prevented accumulation of the active forms of caspase 8 (hydrolysed to Asp384) and caspase 9 (hydrolysed to Asp315) induced by ricin in HepaRG cells. The tested antibodies also prevented a decrease in the intracellular levels of the active forms of Akt 1 kinase (phosphorylated at Ser473) and transcription factor p53 (phosphorylated at Ser46) caused by ricin. The bioassay with antibodies can be considered as a specific method for identifying the toxin in environmental samples.