H. Sugiyama

Staphylococcal enterotoxin. I. Purification

Abstract A procedure for purifying enterotoxin from the Staphylococcus strain S-6 has been outlined. Acid precipitation, adsorption on alumina, precipitation by ethanol, chromatography on IRC-50, and zone electrophoresis on starch were the methods used. The final product shows the presence of only one antigen when tested by the gel-diffusion technique of Oakley and only one peak in the ultracentrifuge. A preparation was obtained that causes emesis in monkeys at approximately 1 μg. nitrogen per dose.

Study of emetic receptor sites for staphylococcal enterotoxin in monkeys.

Summary Bilateral destruction of the area postrema on the floor of the fourth ventricle (chemoreceptor trigger zone) makes rhesus monkeys completely refractory to the emetic action of staphylococcal enterotoxin. The surgically induced resistance is effective against the 2 antigenic types of enterotoxin used. Vagotomy at the level of the diaphragm gave protection in all animals, but in some protection was not complete. The partial protection against enterotoxin-induced emesis in some of the vagotomized monkeys may be due to incompleteness of the vagotomy. If this interpretation of the results is correct, a comomn basis of emesis prevention following staphylococcal enterotoxin feedings may account for the similarity of vomiting response of the area postrema ablated and vagotomized animals. A species difference between cats and rhesus monkeys in the importance of the area postrema region for enterotoxin stimulated vomiting is indicated.

Emetic Action of Bacterial Endotoxin in the Cat.

Summary Intravenously administered bacterial endotoxin (LPS) is an effective emetic for cats. The site of emetic action in this animal was studied by determining the emetic responsiveness to LPS following different denervation procedures. Intrathoracic vagotomy and vagotomy + abdominal sympathectomy had very little influence on subsequent response to LPS. High LPS challenge doses elicited only prodromal signs of vomiting in cats subjected to spinal cord transection at T3-T4. Complete tolerance to emetic action of LPS resulted from abdominal deafferentation produced by vagotomy + spinal cord sectioning. The changes in sensitivity of the cat to the emetic action of intravenously administered staphylococcal enterotoxin were comparable to that for LPS for the different types of denervation.

Sensitivity of thorotrast-treated monkeys to staphylococcal enterotoxin.

Summary Monkeys pretreated with stabilized colloidal thorium dioxide (Thorotrast) are more sensitive to the emetic action of intragastrically administered staphylococcal enterotoxin. The amounts required to elicit vomiting in 50% of the animals tested was reduced to about one-twentieth of that required for untreated monkeys when Thorotrast was given 18 hours before the enterotoxin challenge. The degree of sensitization was the same for both of the 2 different antigenic types of enterotoxin tested. Fresh blood was observed in the vomitus when the interval between Thorotrast and enterotoxin was reduced to 4 hours.

Perphenazine and reserpine as antiemetics for staphylococcal enterotoxin.

Summary Perphenazine and reserpine have significant antiemetic activity against staphylococcal enterotoxin induced emesis in monkeys; chlorpromazine and cyclizine lactate have little or no protective activity. Perphenazine gave the best protection and was effective at 50 μg/kg, intravenously; it inhibited vomiting even when administered 45 min after the enterotoxin had been fed. Pretreatment of monkeys was necessary for protection with reserpine. The effective drug levels did not greatly depress the medullary vomiting center. Perphenazine had some protective effect in dogs being challenged with intravenous injection of enterotoxin.

HYPERFIBRINOGENEMIA AND THROMBOCYTOPENIA AFTER STAPHYLOCOCCAL ENTEROTOXIN.

Summary Parenteral injection of staphylo-coccal enterotoxin increased plasma fibrino-gen levels of rabbits and monkeys. The maximum titer of between 2 to 3 times the pre-challenge concentration was attained in 24 hours after enterotoxin administration. Enterotoxin also depressed the blood serotonin concentration of rabbits. This drop in blood serotonin corresponded to the decrease in number of circulating blood platelets. Both antigenic types of enterotoxin tested induced hyperfibrinogenemia and thrombocytopenia. The dosages required to induce a significant change in these two responses was close to the minimal emetic dose for monkeys by the intravenous route.

Staphylococcal enterotoxin: increased vomiting incidence in monkeys following subemetic doses of dihydroergotamine.

Summary Subcutaneous injection of subemetic dose of dihydroergotamine methane-sulfonate increases the number of Macaca mulatta which vomit following oral administration of staphylococcal enterotoxin. The possibility that increased incidence of vomiting might be due to summation effects of 2 similar pharmacological compounds has been considered, but no adrenolytic effect of enterotoxin corresponding to that of DHE-45 has been found. The other drugs tested have not significantly affected the incidence of emesis in monkeys following feeding of enterotoxin.

Increased Serum Glutamic-Oxalacetic Transaminase of Monkeys following Oral Administration of Staphylococcal Enterotoxin.

Summary Serum glutamic-oxalacetic acid transaminase activity of monkeys after staphylococcal enterotoxin feeding has been studied. There is an elevation to about 2 to 3 times the prefeeding titer within 6-8 hrs after feeding of the toxin. The observations are discussed on the basis that increased serum transaminase activity is due to release of the enzyme into the circulation by damaged cells.

DIARRHEA IN CECECTOMIZED RABBITS INDUCED BY STAPHYLOCOCCAL ENTEROTOXIN.

Summary Cecectomized rabbits (removal of appendix and all of cecum except proximal 3 segments) were challenged intravenously with highly purified staphylococcal entero-toxin. Diarrhea was induced in cecectomized rabbits in doses ineffective for normal rabbits. Average latency was 1¾ hours with recovery from diarrhea within 24 hours. Successive weekly injections of enterotoxin resulted in development of resistance. Pre-treatment of cecectomized rabbits with atro-pine or pyribenzamine gave definite but incomplete protection against enterotoxin-in-duced diarrhea.

Vasoconstrictive action of epinephrine following staphylococcal enterotoxin.

Summary The effects of staphylococcal enterotoxin on the sensitivity of the micro-vasculature of the rabbit meso-appendix to epinephrine was studied. Intravenous injection of even 0.2 μg/kg of the food poisoning toxin induced a significant increase in the vasoconstrictive effect of topically applied epinephrine within 3 hours, Maximum sensitivity occurred about 10 hours after toxin administration and persisted over 18 hours with toxin levels of 1 to 10 μg/kg. A rapidly developing state of hyporeactivity to epinephrine resulted from much larger enterotoxin challenges. Except for the much slower evolution of the state of increased responsiveness to epinephrine, these results are similar to those induced by bacterial endotoxin.