Search

Seven brands of veterinary rabies vaccines are commercially available in Sri Lanka, but there is no established procedure to test the potency of the vaccines at the local level, especially prior to their release. The aim of this study was to test the potency of these vaccines using a mouse challenge test in collaboration with the EU/WOAH/WHO Reference Laboratory for Rabies, ANSES-Nancy, France. Based on the European Pharmacopoeia, the inactivated rabies vaccines complied with the mouse potency test if the estimated potency is ≥1.0 IU in the smallest prescribed dose. Among the eight tested vaccines, four single-dose preparations (Rabisin™, Raksharab™, Nobivac™ RL, and Nobivac™ Rabies) were compliant, with potencies of 12 IU/dose, 7.2 IU/dose, 4.4 IU/dose, and 3.4 IU/dose, respectively. Three of the single-dose preparations (Canvac™ R, Defensor™ 3, and Rabies killed vaccine) were not compliant, with potency values

One of the methods used for controlling cattle rabies in Brazil consists of vaccination. Sometimes, however, rabies occurs in cattle supposedly protected. Since rabies vaccine batches are officially controlled by tests performed on laboratory animals, it is questionable whether the minimal mandatory requirements really correspond to immunogenicity in the target species. We have analyzed the association among potencies of rabies vaccines tested by the NIH test, the contents and form (free-soluble or virus-attached) of rabies glycoprotein (G) in the vaccine batches, and the virus-neutralizing antibodies (VNA) titers elicited in cattle. No correlation was found between G contents in the vaccine batches and the NIH values, whatever the presentation of G. There was no correlation either between NIH values and VNA titers elicited in cattle. There was, however, a positive correlation (r = 0.8681; p = 0.0001) between the amounts of virion-attached G present in the vaccine batches and VNA elicited in cattle. This was not observed when the same analysis was performed with total-glycoprotein or free-soluble glycoprotein. The study demonstrated that NIH values can not predict the effect of the immunogen in cattle. On the other hand, the quantification of virus-attached rabies glycoprotein has a strong correlation with VNA elicited in cattle.

Se desarrolló, estandarizó y evaluó un método indirecto de enzimoinmunoensayo (ELISA), reproducible y rápido, para determinar la concentración de antígenos de vacunas antirrábicas producidas en cultivos celulares (BHK). Se consideró la sensibilidad y la reproducibilidad de los resultados del ELISA in vitro propuesto, en relación con la prueba estándar de potencia NIH in vivo. De los 20 lotes de vacunas estudiados, 14 cumplieron con el Requisito Mínimo de Potencia recomendado por la Organización Mundial de la Salud (OMS), para la prueba NIH in vivo, muestras de los mismos lotes cumplieron con los parámetros del Análisis de Varianza (ANOVA) de la prueba in vitro. La técnica de ELISA propuesta se considera útil como método alternativo rápido para el control de proceso de producción de vacunas antirrábicas de uso veterinario., An indirect enzyme linked immunoassay (ELISA) was developed and evaluated as a rapid and reproducible test to determine the concentration of antigens of rabies vaccine produce in BHK cells. The sensitivity and reproducibility of the results of proposed in vitro ELISA method were compare to the standard in vivo NIH potency test. Of the 20 studied lots of vaccines, 14 fulfilled the Minimum Requirement of Potency recommended by the World Health Organization (WHO), for the NIH test. Samples of the same lots also met the parameters of the ANOVA analysis. The proposed ELISA test showed to be a useful alternative rapid method to apply during "in process" controls of veterinary rabies vaccine., Facultad de Ciencias Veterinarias