Mistletoe lectin quantification by two different enzyme linked immunosorbent assays
In cancer therapy, alternative treatments become more relevant due to the severe side effects of the chemotherapeutics used in the first-line therapy. Viscum album L. (Santalaceae) belongs to the phytotherapeutic drugs applied in alternative cancer treatment . The main ingredients of the aqueous extracts are the mistletoe lectins which belong to the ribosome-inactivating proteins type II . In this work, two different enzyme linked immunosorbent assays (ELISA) for the determination of mistletoe lectins are developed. The methods use specific antibodies against the lectins' a-chain and asialofetuin, a glycoprotein, which binds with high affinity to the b-chain. The first ELISA determines only the a-chain, by capturing and detecting the a-chain alone. The second method quantifies the hololectin by capturing the b-chain and then again detecting the a-chain. The concentration of the hololectin is about 60 per cent of the concentration of the a-chain alone. Only the co-occurence of a- and b-chain, i.e. the hololectin, has the published effect of immune stimulation and induction of apoptosis . To find the correct pharmacokinetic parameters for therapy it is necessary to know the content of hololectin.
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