The biological activities of trichosanthin after coupling to dextran

1. The major biological and pharmacological activities of trichosanthin (TCS) were retained after its covalent coupling to dextran T40. The potency and toxicity was generally reduced. 2. A dose of TCS as low as 0.02 mg/25 g induced 100% mid-term abortion whereas 20 times as much dextran-trichosanthin (DX-TCS) is required to produce the same effect. 3. A third of the mice died at a TCS dose of 0.1 mg/25 g but 4 times as much DX-TCS did not cause any death. 4. DX-TCS suppressed Con A or PHA induced lymphocyte transformation in a dose dependent manner. The potency was decreased as compared to TCS. 5. Both TCS and DX-TCS exhibited a cytostatic effect on cultured tumour cells (PU5 and hepatoma), the former being more potent.