Attempts to quantity Clostridium botulinum type A toxin and antitoxin in serum of two cases of infant botulism in Japan

Serum samples taken from two infant botulism cases during hospitalization were titrated for botulinum toxin by both the intraperitoneal (ip) injection method and the score method in mice. By the ip method, in which death is the only parameter, such low levels of toxin as lower than 4 ip LD50/ml may not be titrated even though the surviving mice show abdominal palsy. By the score method based on the degree of abdominal palsy, such low levels of toxin as 1.1 and 0.8 ip LD50/ml were detected in specimens of one of the patient's serum. No antitoxin was demonstrated in either case of infant botulism by applying the score method. It is not known whether spontaneous recovery from infant botulism is due to the antitoxin production.

Titration of botulinum antitoxin of low levels by the score method

Botulinum antitoxin is commonly titrated by injecting a mixture of toxin and antitoxin into mice and by utilizing deaths as a marker to measure the amount of unneutralized toxin. We attempted to titrate antitoxin by converting the severity of symptoms (notably palsy) and time-to-death in days into scores. In neutralization tests with toxin levels at 5.9 LD50 and 23.5 LD50, a linear relationship was obtained for antitoxin dose in a range between 0.03 to 0.003 IU/ml. Statistical analysis showed that homogeneity of variance or slope was not denied for the scores obtained on any day from the first to the fourth days after injection, demonstrating that this method can titrate accurately antitoxin of such a low level as 0.003 IU/ml within 4 days after injection.

Kinetics study of immunological response to Clostridium botulinum toxin

A double-antibody enzyme-linked immunosorbent assay (ELISA) for detection of humoral antibody to type A botulinal toxin was developed. This assay was used to study the kinetics of antibody response of a volunteer to botulinal toxoid. The circulating type A antitoxin was first detected by the ELISA 2 weeks after the first booster injection of the toxoid. The antibody titer stayed level until the second booster at 12 weeks. The titer then continued to rise throughout the remaining study period. The neutralizing antibody to type A toxin was detected by mouse assay 15 weeks after detection of antitoxin by the ELISA.

Antitoxin levels in botulism patients treated with trivalent equine botulism antitoxin to toxin types A, B, and E

Serum levels of equine-botulism antitoxin to toxin types A, B, and E were measured in four type-A botulism patients who had received equine-botulism antitoxin. High circulating levels capable of neutralizing in excess of 1 X 10(8), 9 X 10(7), and 6 X 10(6) 50% mouse lethal doses of toxin of types A, B, and E, respectively, were detected. There was little depletion of type-A antitoxin even though two of the patients had circulating type-A toxin before treatment. The half-life for antitoxin persistence for one patient was calculated as being 6.5, 7.6, and 5.3 days for antitoxin types A, B, and E, respectively. Antitoxin levels were not proportionate to the amount (range, 2-4 vials) injected and did not appear to be affected by whether the route of administration was iv or im. Peak serum levels of antitoxin were 10-1,000 times higher than amounts needed to neutralize the toxin measured in the serum of these and other patients with botulism.

An outbreak of type C botulism in captive monkeys

In an outbreak of type C botulism in a group of captive primates, six squirrel monkeys, six white throated capuchin monkeys and two weeper capuchin monkeys succumbed rapidly and died. Clostridium botulinum type C toxin was detected in the remains of the chopped chicken feed and in nine of 11 blood samples and one of three stomach contents samples from the affected animals.

The antibody response of cattle to Clostridium botulinum types C and D toxoids

The resistance of cattle with varying serum-antitoxin titres was determined by per os challenge. The results proved that a solid immunity can be produced against C. botulinum toxins C1 and D. The immune response of cattle to various quantities of C. botulinum C1 and D toxoids, aluminium-phosphate-adsorbed and in water-in-oil emulsion was investigated. The response to antigen in water-in-oil emulsion was far superior to the other when they were used for primary and secondary stimuli. When cattle had been given a solid basic immunity with 2 injections of antigen in water-in-oil emulsion, essentially the same booster effect was obtained with antigen in water-in-oil emulsion and in aqueous solution. Only some of the animals injected intramuscularly with antigens in water-in-oil emulsion developed local lesions. These lesions were not large and their histological picture indicated a noticeable decline in severity within 20 weeks. A case is thus made out for the use of C. botulinum C1 and D toxoids in water-in-oil emulsion for the primary and secondary stimuli and an aqueous solution of these antigens for any booster stimulus as an improved method of protecting cattle against botulism.