Experiments on monkeys with cholera toxin partially purified and detoxified with formol and glycine.

Cholera toxoid partially purified and detoxified with formol and glycine and inoculated in monkeys proved safe. Histological examination revealed no changes in the skin of the animals treated. Blood samples taken from monkeys immunized with 2 doses of toxoid 12 days after the second inoculation revealed appreciable levels of antitoxin in the animals that had received two 100-mug doses of toxoid. The monkeys vaccinated with toxoid, when inoculated with challenge doses of cholera toxin, had the capacity to neutralize the toxin. Detoxification with formol and glycine may be the first step towards the preparation of a highly purified, innocuous, and antigenic cholera toxoid.