RESUMEN
The need for a reference cholera antitoxin to serve as a standard for the calibration of cholera enterotoxin and toxoid as well as for measurement of the antitoxin response in animals and patients was recognized by the NIH Cholera Advisory Committee, NIAID, DHEW, USA. Two cholera antitoxins have been used for several years as provisional references, but neither was considered to embody all of the properties of an ideal standard. Accordingly, a lot of cholera antitoxin was prepared by immunization of goats with a formalinized, highly purified cholera toxin adsorbed on aluminum phosphate adjuvant. Booster injections were given at 8, 16 and 24 weeks. Plasma samples obtained from the 25 to 27 week bleedings were converted to serum, pooled, and freeze-dried. This serum possessed both high and constant toxin neutralizing activity in rabbit skin, rabbit ileal segment, mice, Y-1 adrenal cells and Chinese hamster ovary cells, and had high avidity by the rabbit skin assay. Hemagglutination tests gave identical values. It was shown to be highly specific by gel diffusion, but flocculation was relatively poor. On the basis of specificity, high avidity and toxin-neutralizing capacity this goat antitoxin (NIH Lot 1) was considered superior to previous provisional standards and is proposed as a satisfactory standard reference reagent.
Asunto(s)
Antitoxinas/normas , Vacunas contra el Cólera/normas , Cólera/inmunología , Anticuerpos Antibacterianos/inmunología , Antitoxinas/inmunología , Células Cultivadas , Vacunas contra el Cólera/inmunología , Sueros Inmunes/inmunología , Cooperación Internacional , Pruebas de Neutralización , Estándares de Referencia , Estados Unidos , United States Dept. of Health and Human ServicesRESUMEN
The papers present the results of a survey of the usage, assay and specification of veterinary clostridial sera and vaccines in 23 countries. Thirteen of the countries use up to 8 different antisera. All the countries use vaccines, which are prepared from 13 species and types of clostridia. Vaccines containing up to 8 such components are commonly employed. Criteria for the design and interpretation of assays are discussed and evidence for efficacy summarized.
Asunto(s)
Antitoxinas/normas , Vacunas Bacterianas/normas , Clostridium/inmunología , Animales , Toxinas Bacterianas/normas , Antitoxina Botulínica/normas , Clostridium botulinum/inmunología , Clostridium perfringens/inmunología , Clostridium tetani/inmunología , Cobayas , Ratones , Antitoxina Tetánica/normasRESUMEN
The preparation of laboratory standard antitoxins against Cl. perfringens beta and epsilon toxins is described. These antitoxins are suitable for the quantitative determination of the corresponding antigens by means of the flocculation test. The flocculation test was, however, shown to be more suitable for determining the antigenic value of fresh toxoid rather than toxoid stored without neutralization of excess formalin. A maximal immunity response to alum-precipitated epsilon toxoid was obtained in sheep with two injections containing 90 Lf per dose. The interval between these injections may vary from 2 to 6 weeks. The serum-antibody titres after the primary and secondary injections or after a booster dose given before 12 months after the primary injection did not remain above the protective level in most of the sheep injected for longer than about 5 months. When a sound basic immunity is established the degree of protection following on a booster dose given 12 months later is complete for at least 12 months. An alum-precipitated vaccine containing 25 Lf epsilon toxoid per dose is adequate. The decline in the serum-antibody titre during the first year of vaccination could be eliminated by the use of the antigen in water-in-oil emulsion. Lambs from immune dams were protected for at least up to 13 weeks of age. A satisfactory level of circulating antitoxin against Cl. perfringens beta toxin could be produced in ewes by vaccinating them with APT containing 6.25 Lf beta toxoid per dose. The primary and secondary injections could be separated by 2, 3, 4 or 5 weeks without changing the end result. A booster dose given 2 months before parturition was satisfactory.