Publications by authors named "Paul Stickings"

Chlamydia trachomatis (Ct) serology is an important tool for monitoring infection and disease burden but there are currently no formal reference reagents to harmonize results reporting. Our objective was to develop a panel of candidate reference reagents with reactivity against the major outer membrane protein (MOMP) and virulence factor (pgp3) antigens. Plasma packs from females (20-40 years old) were screened against MOMP and pgp3 antigens and selected positive and negative samples pooled to create a panel of candidate antibody reference reagents that were tested in two laboratories.

View Article and Find Full Text PDF

Antigen identity, quantity and integrity are key factors to be evaluated as part of consistency testing of tetanus vaccines. Here we have developed a monoclonal antibody sandwich ELISA to measure the relative amount and quality of tetanus toxoid (TTxd) in human and animal tetanus vaccines. The ELISA is highly specific, has good dilutional linearity, and is suitable for detecting TTxd in a range of different products.

View Article and Find Full Text PDF

An international hybrid meeting held 21-22 June 2023 in Ottawa, Canada brought together regulators, scientists, and industry experts to discuss a set of principles and best practices in the development and implementation of standards. Although the use of international standards (ISs) and international units (IUs) has been an essential part of ensuring human and animal vaccine quality in the past decades, the types and uses of standards have expanded with technological advances in manufacture and testing of vaccines. The needs of stakeholders are evolving in response to the ever-increasing complexity, diversity, and number of vaccine products as well as increasing efforts to replace animal-based potency tests with in vitro assays that measure relevant quality attributes.

View Article and Find Full Text PDF

Here we report the results of a study to establish a replacement WHO International Standard (IS) for tetanus toxoid for use in flocculation test. The standard was calibrated in flocculation units (Lf) against the 2nd IS using the Ramon flocculation method. At its 70th meeting in October 2019, WHO ECBS established the material (coded 16/302) as the 3rd WHO IS, with an assigned value of 970 Lf/ampoule from the results of seventeen laboratories across ten different countries.

View Article and Find Full Text PDF

At present, quality control of diphtheria vaccines by both manufacturers and national control laboratories relies heavily on in vivo assays to confirm potency. As part of the VAC2VAC project we have developed a monoclonal antibody (mAb) enzyme-linked immunosorbent assay (ELISA) to measure the relative amount and quality of diphtheria toxoid (DTxd) in diphtheria-tetanus based vaccines and believe this test has the potential to play a key role in a control strategy no longer including an in vivo potency test. The mAb ELISA is highly specific, has good dilutional linearity, and is suitable for detecting DTxd in a range of different human vaccine products.

View Article and Find Full Text PDF

For the batch release of vaccines, potency release assays are required. Non-animal in vitro tests have numerous advantages and are preferred; however, several vaccines are still released using in vivo assays. Their major drawback is the inherent variability with its practical implications.

View Article and Find Full Text PDF

Regulatory authorities require veterinary batch-release testing to confirm vaccine potency and safety, but these tests have traditionally relied on large numbers of laboratory animals. Advances in vaccine research and development offer increasing opportunities to replace in vivo testing, and some stakeholders have made significant progress in incorporating 3Rs elements in quality control strategies. A three-part event series entitled "3Rs Implementation in Veterinary Vaccine Batch-Release Testing: Current state-of-the-art and future opportunities" was jointly organized by the Animal-Free Safety Assessment Collaboration, HealthforAnimals, and the International Alliance of Biological Standardization.

View Article and Find Full Text PDF

The International Standard for Diphtheria Antitoxin Equine is essential for the standardisation of assays used to determine the potency of therapeutic diphtheria antitoxin products produced from equine serum. This paper describes the production and characterization of the 2nd International Standard for Diphtheria Antitoxin Equine and its calibration in International Units. Calibration was performed by toxin neutralization test in vivo and in vitro (Vero cell assay), and potency was expressed relative to the 1st International Standard to ensure continuity of the International Unit.

View Article and Find Full Text PDF

Routine batch quality testing before vaccine release, notably for potency evaluation, still relies on animal use for several animal and human vaccines. In this context, the VAC2VAC project is a public-private consortium of 22 partners funded by EU whose the main objective is to reduce the number of animal used for batch testing by developing immunoassays that could be implemented for routine potency assessment of vaccines. This paper focused on the development of a Luminex-based multiplex assay to monitor the consistency of antigen quantity and quality throughout the production process of DTaP vaccines from two human vaccine manufacturers.

View Article and Find Full Text PDF

Introduction: There are rational arguments to replace existing potency and safety assays for batch release testing of vaccines with more advanced non-animal techniques to measure critical quality attributes. However, the introduction of alternatives to replace release assays of authorized vaccines is challenging.

Areas Covered: This report describes the hurdles encountered in substituting assays and ways to overcome these and provides arguments why more advanced alternatives are superior, not only as a tool to monitor the quality of vaccines but also from a practical, economical, and ethical point of view.

View Article and Find Full Text PDF

The UK National Centre for the Replacement, Refinement, and Reduction of Animals in Research (NC3Rs) has been tasked by the World Health Organization (WHO) to review the extent to which animal-based testing methods are described in their manuals, guidelines and recommendations for vaccines and biotherapeutics. The aim is to identify and recommend where updates to these documents can lead to an increased and more harmonised adoption of 3Rs principles (i.e.

View Article and Find Full Text PDF

When preparing biological reference materials, the stability of the lyophilized product is critical for long-term storage, particularly in order to meet WHO International Standards, which are not assigned expiry dates but are expected to be in use for several decades. Glass ampoules are typically used by the National Institute for Biological Standards and Control (NIBSC) for the lyophilization of biological materials. More recently, a clear need has arisen for the filling of smaller volumes, for which ampoules may not be optimal.

View Article and Find Full Text PDF

The past 18 months have seen an unprecedented approach to vaccine development in the global effort against the COVID-19 pandemic. The process from discovery research, through clinical trials and regulatory approval often takes more than 10 years. However, the critical need to expedite vaccine availability in the pandemic has meant that new approaches to development, manufacturing, and regulation have been required: this has necessitated many stages of product development, clinical trials, and manufacturing to be undertaken in parallel at a global level.

View Article and Find Full Text PDF

Tetanus antitoxin, produced in animals, has been used for the prevention and treatment of tetanus for more than 100 years. The availability of antitoxins, ethical issues around production, and risks involved in the use of animal derived serum products are a concern. We therefore developed a llama derived single-domain antibody (VHH) multimer to potentially replace the conventional veterinary product.

View Article and Find Full Text PDF

Batch release testing for human and veterinary tetanus vaccines still relies heavily on methods that involve animals, particularly for potency testing. The quantity and quality of tetanus antigen present in these products is of utmost importance for product safety and clinical effect. Immunochemical methods that measure consistency of antigen content and quality, potentially as an indicator of potency, could be a better choice and negate the need for an in vivo potency test.

View Article and Find Full Text PDF

Immunoassays are used for routine potency assessment of several vaccines, in some cases having been specifically developed as alternatives to in vivo potency tests. These methods require at least one well characterised monoclonal antibody (mAb) that is specific for the target antigen. In this paper we report the results of the comprehensive characterisation of a panel of mAbs against diphtheria with a view to select antibodies that can be used for development of an in vitro potency immunoassay for diphtheria vaccines.

View Article and Find Full Text PDF

Transition to in vitro alternative methods from in vivo in vaccine release testing and characterization, the implementation of the consistency approach, and a drive towards international harmonization of regulatory requirements are most pressing needs in the field of vaccines. It is critical for global vaccine community to work together to secure effective progress towards animal welfare and to ensure that vaccines of ever higher quality can reach the populations in need in the shortest possible timeframe. Advancements in the field, case studies, and experiences from Low and Middle Income Countries (LMIC) were the topics discussed by an international gathering of experts during a recent conference titled "Animal Testing for Vaccines - Implementing Replacement, Reduction and Refinement: Challenges and Priorities".

View Article and Find Full Text PDF

High protein concentration products for targeted therapeutic use are often freeze-dried to enhance stability. The long-term storage stability of freeze-dried (FD) plasma-derived Immunoglobulin G (IgG) from moderate to high concentrations (10-200 mg/mL) was assessed. Monomer content, binding activity and reconstitution times were evaluated over a 12-month period under accelerated and real-term storage conditions.

View Article and Find Full Text PDF

Diphtheria is an infectious disease caused by Corynebacterium diphtheriae. The bacterium primarily infects the throat and upper airways and the produced diphtheria toxin (DT), which binds to the elongation factor 2 and blocks protein synthesis, can spread through the bloodstream and affect organs, such as the heart and kidneys. For more than 125 years, the therapy against diphtheria has been based on polyclonal horse sera directed against DT (diphtheria antitoxin; DAT).

View Article and Find Full Text PDF

We previously developed an ELISA assay for detection of tetanus toxoid antigen in tetanus vaccines for human use. Tetanus vaccines for veterinary use are qualitatively different to those used in humans, often containing a larger number and variety of non-tetanus antigens in the multi-valent products, and adjuvants that are not found in human vaccines. We assessed performance of the capture ELISA with a range of veterinary tetanus vaccines as a first step towards development of an immunoassay as a potential in vivo potency substitute.

View Article and Find Full Text PDF

Botulinum neurotoxins (BoNTs) type A and type B are commonly used as biopharmaceutics for neurological diseases, uniquely allowing months-long paralysis of target muscles. Their exquisite neuronal specificity is conferred by a multistep process of binding, internalization, cytosolic escape and cleavage of the neuron-specific proteins, SNAP-25 and vesicle-associated membrane proteins (VAMPs), ultimately to inhibit secretion of neurotransmitters. Currently the mouse lethality bioassay is the only available method for quality control testing of VAMP-cleaving botulinum products.

View Article and Find Full Text PDF

Botulinum toxins (BoNTs), of which there are seven serotypes, are among the most potent neurotoxins, with serotypes A, B and E causing human botulism. Antitoxins form the first line of treatment for botulism, and functional, highly sensitive in vitro methods for toxin neutralization are needed to replace the current in vivo methods used for determination of antitoxin potency. In this preliminary proof of concept study, we report the development of a neutralization test using the neuroblastoma SiMa cell line.

View Article and Find Full Text PDF
Article Synopsis
  • - The European Partnership for Alternative Approaches to Animal Testing (EPAA) held a workshop to discuss improving the safety testing of biological medicines by promoting the reduction of animal testing requirements.
  • - Participants aimed to replace traditional animal tests with validated in vitro methods for assessing the potency of vaccines, highlighting the need for global agreement on scientific principles.
  • - The workshop called for early involvement of key regulators and manufacturers in discussions to establish new testing requirements and foster international collaboration on alternative testing methods.
View Article and Find Full Text PDF

A 2-yr-old male gyrfalcon ( Falco rusticolus ) was presented for severe and generalized muscle spasticity and pododermatitis. The falcon had been treated for pododermatitis over the previous 4 mo. Muscle rigidity and spasms involved the entire bird but were more severe on the right leg.

View Article and Find Full Text PDF

We present the results of a collaborative study for the establishment of a replacement International Standard (IS) for diphtheria toxoid for use in flocculation test and its calibration in Lf units. Calibration was performed using Ramon flocculation method, standardized using the 2nd IS. The candidate standard was assigned a unitage of 1870 Lf/ampoule based on results from 25 laboratories in 15 different countries and was established as the 3rd IS for diphtheria toxoid for use in flocculation test by the WHO Expert Committee on Biological Standardization (ECBS) in October 2015.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessionm2k6icat46uf68hek24gqr98jq6s0q10): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once