Developments in Biologicals

The development of countermeasures to support an effective response to Transboundary Animal Diseases (TAD) poses a challenge on a global scale and necessitates the coordinated involvement of scientists from government, industry and academia, as well as regulatory entities. The Agricultural Defense Branch under the Chemical and Biological Defense Division (CBD) of the Department of Homeland Security (DHS), Science and Technology Directorate (S&T) supports this important mission within the United States. This article provides an overview of the Agricultural Defense Branch's vaccine and diagnostic TAD project...

No abstract text is available yet for this article.

A proposed definition of a stability indicating assay is "a validated quantitative analytical procedure that can detect changes over time in the pertinent properties of the product" (Federal Register/Vol. 75 No. 180/Friday, September 17, 2010/Proposed Rules). In vaccines intended for veterinary usage, the potency assay has traditionally been used as a measure of stability. Some potency assays may be acceptable as stability indicating assays, whereas other potency assay will not meet the criteria for stability indicating assays...

The Consistency Approach offers the possibility of reducing the number of animals used for a potency test. However, it is critical to assess the effect that such reduction may have on assay performance. Consistency of production, sometimes referred to as consistency of manufacture or manufacturing, is an old concept implicit in regulation, which aims to ensure the uninterrupted release of safe and effective products. Consistency of manufacture can be described in terms of process capability, or the ability of a process to produce output within specification limits...

Next generation, foot-and-mouth disease (FMD) molecular vaccines based on replication deficient human adenovirus serotype 5 viral vectored delivery of FMD capsid genes (AdFMD) are being developed by the United States Dept. of Homeland Security and industry partners. The strategic goal of this program is to develop AdFMD licensed vaccines for the USA National Veterinary Stockpile for use, if needed, as emergency response tools during an FMD outbreak. This vaccine platform provides a unique opportunity to develop a set of in vitro analytical parameters to generate an AdFMD vaccine product profile to replace the current lot release test for traditional, inactivated FMD vaccines that requires FMDV challenge in livestock...

No abstract text is available yet for this article.

There is great interest in the veterinary vaccine field to move away from in vivo release tests for vaccines to reduce cost and testing time, improve consistency and of course the 3Rs (reduce, refine, replace). A brief overview of Good Manufacturing Practice (GMP) and the consistency approach is discussed below and an overview of how manufacturers can use the consistency approach and GMP controls along with statistical analysis of processes at each stage of the production process (starting materials, antigen and finished product) to build in quality and reduce the need for in vivo finished product tests...

Testing vaccines involves expensive animal models and extensive in vitro characterization. Techniques such as ELISA and ELISPOT are traditionally used to measure immunogenicity, assess the potency of recombinant vaccines and detect the presence of biological contaminants. However, these time-proven techniques suffer from technical limitations affecting the overall vaccine development process. Limitations include: consumption of large volumes of biological sample (eg. plasma), high variability, and limited dynamic range...

The standard requirement for serial release potency testing of Leptospira bacterins in the United States is the hamster vaccination challenge test. It is a test that uses a large number of animals experiencing pain or distress, takes weeks to conduct, can be expensive and requires that laboratory personnel handle a viable zoonotic pathogen. In an effort to address these concerns, the United States Department of Agriculture (USDA) developed an in vitro method for potency testing of four Leptospira serovars. This enzyme-linked immunosorbent assay (ELISA) was subsequently validated in the target species...

Vaccines play a key role in the control of viral diseases both in humans and in animals. In order to ensure the quality and consistency of vaccines they are extensively tested, including potency control of individual batches. In the case of vaccines against rabies the most widely used test for batch potency control is the National Institutes of Health (NIH) test. The NIH test is performed in mice leading to the consumption of thousands of animals every year. Protection against rabies after vaccination is associated with neutralizing antibodies directed against the viral glycoprotein (G)...

Despite significant investment and technical efforts, veterinary vaccine manufacturers continue to experience challenges with the transition from historic animal-based potency methods to in vitro potency assays. These challenges have a number of contributing factors, including an inadequate understanding of protective antigens and epitopes, a lack of ruggedness and discriminating capabilities in evolving immunologically-based methods, inconsistencies between methods used for in-process antigen measurement and finished product potency, and a lack of clear methods to characterize the finished formulation (including complex adjuvants)...

This paper proposes a program under which the use of animals for requalification of in vitro potency tests could be eliminated. Standard References (USDA/CVB nomenclature) would be developed, characterized, stored and monitored by selected reference laboratories worldwide. These laboratories would employ scientists skilled in protein and glycoprotein chemistry and equipped with state-of-the-art instruments for required analyses. After Standard References are established, the reference laboratories would provide them to the animal health industry as "gold standards"...

The biological nature of IVMPs leads to some unavoidable batch to batch variation in production. The potency test is part of the quality control of the finished product intended to confirm consistency of production and that each batch is formulated equivalent to batches that have been demonstrated to be efficacious. Adequate validation of potency tests is essential to ensure that the results of the assays accurately reflect the amount, titre, or potency of the active substance measured and to indicate the limitations on the accuracy of the measurements to be expected from the test used...

The relative haemagglutinin-neuraminidase (HN) antigen content of inactivated Newcastle disease virus (NDV) vaccines from different manufacturers was determined by means of an Enzyme-Linked Immunosorbent Assay (ELISA) according to Monograph 870 of the European Pharmacopoeia (Ph. Eur.). Wide ranges of reactivity of the different products were observed. When comparing the antibody responses from chickens vaccinated with vaccines showing either high or low reactivity in the antigen ELISA it was found that approximately the same titres of antibodies were induced in the chickens...

The development of an alternative in vitro potency test required experimental studies, which were performed in-house and in collaboration with other laboratories (Official Medicines Control Laboratories, Manufacturers), coordinated by EDQM (European Directorate for the Quality of Medicines & HealthCare). This paper provides background information concerning the development of the quantitative ELISA for inactivated Newcastle disease virus (NDV) antigen, which was added in the European Pharmacopoeia monograph as an in vitro batch potency test...

Vaccines to protect against clostridial diseases are among the most common veterinary biologicals. Each batch of these materials is subjected to a variety of toxicity and antigenicity tests. The potency of the final vaccine is then assessed by Toxin Neutralisation Test (TNT). All of these tests use mice and have lethal endpoints. Development of alternatives for potency testing was based on ELISAs able to measure antibody levels to the specific toxins relative to a standard serum with a defined unitage. These alternative assays were shown to correlate with the relevant TNTs and have been accepted by European Regulatory Authorities as batch release potency tests...

Ph. Eur. Monograph 0064 "Swine erysipelas vaccine (inactivated)" currently advises mouse serology for batch potency testing. However, technological advances in vaccine production, improved quality control systems and comprehensive post marketing surveillance increasingly promote the acceptance of non-animal approaches for batch release testing. Protein and immune profiles of inactivated swine erysipelas vaccines obtained by SDS-PAGE and Western Blot might offer a convenient global and functional in vitro alternative...

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...

Batch potency testing of rabies vaccines could be done by challenge, measurement of serum response or antigen quantification. Here, we show the development of a serological test that was successfully validated for use in batch release. The serological test is based on serum neutralization (SNT). The correlation to the NIH challenge was demonstrated by batches passing respectively failing equivalently in the NIH and SNT. The SNT provides information on immunogenicity and exhibits several advantages to the NIH: 1) SNT uses many fewer animals for batch release...

Veterinary vaccines contribute to improved animal and human health and welfare by preventing infectious diseases. However, testing necessary to ensure vaccine effectiveness and safety can involve large numbers of animals and significant pain and distress. NICEATM and ICCVAM recently convened an international workshop to review the state of the science of human and veterinary vaccine potency and safety testing, and to identify priority activities to advance new and improved methods that can further reduce, refine and replace animal use...