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Ames, IA, United States

Ingebritson A.L.,Center for Veterinary Biologics | Roth J.A.,Iowa State University | Hauer P.J.,National Veterinary Services Laboratories
Vaccine | Year: 2010

A collection of swine, fish, and cetacean Erysipelothrix rhusiopathiae strains representing 16 serotypes was analyzed for possession of the three currently recognized surface protective antigen (spa)-types: spaA, spaB, and spaC. Polymerase chain reaction (PCR) assays and Western blotting with a SpaA-specific monoclonal antibody demonstrated that spa-type is not confined to specific serotype groups. In particular, the spa-type of strains of aquatic origin was more variable than those of terrestrial origin, and possessed the distinct ability to express more than one spa. In a cross-protection study, mice immunized with an E. rhusiopathiae serotype 2 SpaA-type strain and challenged with various E. rhusiopathiae isolates were completely protected against strains exhibiting a single homologous spa, but variably protected against strains possessing a heterologous spa or those harboring more than one spa-type. Source


Vaccination of domestic animals against rabies creates a critical barrier between wildlife reservoirs and the human population. Ensuring these vaccines are potent and effective is paramount in preventing human exposure to this deadly and costly disease. The National Institutes of Health (NIH) test is, at present, the most widely used and internationally recommended potency assay for batch testing inactivated rabies vaccines. This test has numerous inherent limitations and disadvantages, including a lack of precision. The NIH test requires a large number of animals and involves unrelieved pain and suffering. A relevant in vitro assay should provide a more accurate, reproducible, rapid, safe, and humane rabies vaccine potency test. Source


The Virus-Serum-Toxin Act of 1913 provides the legal basis for the regulation of veterinary biological products in the United States, and the USDA's Center for Veterinary Biologics (CVB) has the authority to issue licenses and permits for such products. The law was intended to establish standards and control the importation of products into the United States as well as the domestic distribution of products, assuring the purity, safety, potency, and efficacy of veterinary biological products. Prelicensing data evaluation procedures are designed to assess the quality of each product and support product label claims. Under the standard licensing process, this spectrum of evaluation includes complete characterization of seed material and ingredients, and laboratory- and host-animal safety and efficacy studies. Post-license testing includes batch tests for purity, safety, and potency. As part of the production and testing of regulated products, procedures involving animals are used to validate product requirements for safety, potency, and efficacy. Incorporating alternative methods to reduce, refine, and replace the use of animals in the development and testing of veterinary biological products has been a strategic goal for the CVB for several decades, and current licensing processes and policies are designed to support and encourage the shift from animal-based methods to alternative practices while ensuring that regulated products continue to be safe and effective. © 2011. Source


Kulpa-Eddy J.,Animal and Plant Health Inspection Service | Dusek D.,Center for Veterinary Biologics
Procedia in Vaccinology | Year: 2011

Biologics are usually produced from live organisms, and the manufacturing process often involves a degree of natural variability. Characterization of biologics such as vaccines is inherently difficult due to the complex molecular structure of the antigens they contain and the presence of excipients such as preservatives and adjuvants that can interfere with testing. Therefore, each batch, lot, or serial produced must be tested before market release to ensure that the product complies with regulatory standards. This batch release testing emphasizes quality control of the final product and may be characterized by an extensive use of laboratory animals. The consistency approach is based upon the principle that the quality of a biologic is the result of the strict application of a quality system and consistent production. Subsequent batches are determined to be similar to clinically evaluated batches and therefore acceptable for release through the in-process testing that comprises this quality system. The European Centre for Validation of Alternative Methods (ECVAM) organized international workshops in 2006 and 2010 to discuss the consistency approach and its potential to reduce the number of animals used in testing of biological products. This paper provides an overview of these workshops. © 2011. Source


Thiele T.L.,Center for Veterinary Biologics | Stuber T.P.,National Veterinary Services Laboratories | Hauer P.J.,National Veterinary Services Laboratories
Vaccine | Year: 2013

Clostridium sordellii is a Gram positive anaerobic bacterium that causes multiple disease syndromes in both humans and animals. As with many clostridial pathogens, toxins contribute to the virulence of C. sordellii. Two large toxins have been identified: a lethal toxin (TcsL) and a hemorrhagic toxin (TcsH) which are similar in structure and function to Clostridium difficile toxin B (TcdB) and toxin A (TcdA), respectively. While TcdA, TcdB, and TcsL have been extensively studied, relatively little is known about TcsH. This study elucidated the TcsH gene sequence using whole genome sequencing, compared the genotype with toxin expression of 52 C. sordellii strains, and examined the role of TcsH in batch release potency tests required for veterinary vaccines licensed in the United States and other testing utilizing WHO standard antitoxin. Data from this study will assist in future research to clarify the TcsH contribution to the pathogenesis of C. sordellii infections and may aid in the development of improved vaccines. © 2013. Source

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