Sulfhydryl-dependent proteases produced by Clostridium botulinum types A, B, and F, Clostridium histolyticum, Clostridium sporogenes and Clostridium perfringens activate preferentially type E over type B progenitor toxin but less efficiently than trypsin. The results explain why activable toxin is demonstrable in culture of a strongly proteolytic type B strain.

View full abstract

Purified C. pert ringens type A enterotoxin fed orally in an amount of 5 mg caused both vomiting and diarrhea in the monkey only when the gastric juice had been neutralized. Exposure of enterotoxin to pH 4.0 or below rapidly destroyed the activity. All three monkeys receiving sodium bicarbonate and 2.4×10¹⁰ viable cells grown in DS medium developed diarrhea, and only one of them vomited once. The diarrhea lasted for 13, 18 and 19 hr. The symptoms were similar to those reported in human cases of C. perfringens food poisoning. These results have verified the general notion that C. perfringens food poisoning should be categorized as a true “intravital intoxication”.
The reversed passive hemagglutination test detected enterotoxin directly in most fecal samples. This method may be applicable for diagnosis of human cases of C. per fringens food poisoning.
Neither enterotoxin nor anti-enterotoxin was detected in serum samples taken from any monkey up to 21 days after the challenge. We are tempted to conclude, therefore, that no significant amount of C. perfringens enterotoxin is absorbed from the intestine.

View full abstract

An outbreak of echovirus type 11 (E-11) infection occurred among newborn babies in a hospital maternity unit in the summer of 1971. The results of studies are as follows:
1) Forty-one of 188 infants developed febrile illness with stomatitis during one and a half months from July to September. E-11 was isolated from stool specimens of 14 infants and two throat swabs. Antibody response to the virus was shown in all the 19 cases examined. Some of their mothers were suffering from subclinical infection.
2) The isolates were identified as a variant of E-11 which is not neutralized with antiserum against prototype E-11. Antiserum against the current virus neutralized both current and prototype viruses.
3) Sucrose gradient centrifugation of sera from infants revealed that the neutralizing antibody activity resided more predominantly in 19S than in 7S fractions. These antibodies reacted more specifically with the current strain than with the prototype Gregory strain.

View full abstract

Tumors induced in Japanese quails by the Schmidt-Ruppin strain of Rous sarcoma virus were examined histopathologically. The following three phases were recognized in the quails whose tumors regressed finally (regressor) . Phase I was between days 4 and 7 of virus inoculation, when growth of tumor cells was seen with predominant infiltration of heterophils. Phase II, from days 10 to 14, was characterized by necrosis of tumor cells and focal accumulation of lymphoid cells which frequently formed follicle-like nodules. In phase III from days 18 to 24, tumor cells and heterophils disappeared, whereas diffuse infiltration of lymphoid cells, plasma cells and histiocytes were demonstrated.
In the quails whose tumors progressed (progressor), growth of tumor cells and infiltration of heterophils at phase I seemed to follow a pattern similar to that of regressors, but subsequent infiltration and focal accumulation of lymphoid cells were rare. These morphological findings suggested an immunological reaction against tumor cells by lymphoid cells.

View full abstract