Production and immunogenic efficacy of botulinum tetravalent (A, B, E, F) toxoid

A tetravalent (type A, B, E and F) toxoid was produced and its efficacy and safety were assessed. The toxoid preparation was inoculated from two to five times to 15 healthy adult volunteers participating in botulinum toxin research. The serum samples taken from the toxoid recipients were titrated for the antitoxin potencies by enzyme-linked immunosorbent assay (ELISA) and the neutralization test. The neutralizing and ELISA titers were too low to correlate each other. The mean neutralization titer of four recipients in 9 months after three doses of toxoid was about 0.1 IU/ml for each of the four types, whereas, the one receiving five doses possessed a higher titer. Since the amount of the toxin handled in laboratory work is usually not so large, three or more doses of the present toxoid will bestow sufficient immunity on the workers participating in botulinum research. Nevertheless booster injections might be desirable to those at higher risk, handling the toxin of a high concentration.