Development of an in Vitro Potency Assay for Anti-anthrax Lethal Toxin Neutralizing Antibodies

Lethal toxin (LT) of Bacillus anthracis reduces the production of a number of inflammatory mediators, including transcription factors, chemokines and cytokines in various human cell lines, leading to down-regulation of the host inflammatory response. Previously we showed that the reduction of interleukin-8 (IL-8) is a sensitive marker of LT-mediated intoxication in human neutrophil-like NB-4 cells and that IL-8 levels are restored to normality when therapeutic monoclonal antibodies (mAb) with toxin-neutralising (TN) activity are added. We used this information to develop cell-based assays that examine the effects of TN therapeutic mAbs designed to treat LT intoxication and here we extend these findings. We present an in vitro assay based on human endothelial cell line HUVEC jr2, which measures the TN activity of therapeutic anti-LT mAbs using IL-8 as a marker for intoxication. HUVEC jr2 cells have the advantage over NB-4 cells that they are adherent, do not require a differentiation step and can be used in a microtitre plate format and therefore can facilitate high throughput analysis. This human cell-based assay provides a valid alternative to the mouse macrophage assay as it is a more biologically relevant model of the effects of toxin-neutralising antibodies in human infection

Vaccine

Influenza vaccines are the most effective intervention to prevent the substantial public health burden of seasonal and pandemic influenza. Hemagglutinin (HA), as the main antigen in inactivated influenza vaccines (IIVs), elicits functional neutralizing antibodies and largely determines IIV effectiveness. HA potency has been evaluated by single-radial immunodiffusion (SRID), the standard in vitro potency assay for IIVs, to predict vaccine immunogenicity with a correlation to protective efficacy. We previously reported that limited trypsin digestion (LTD) selectively degraded stressed HA, so that an otherwise conformationally insensitive biophysical quantification technique could specifically quantify trypsin-resistant, immunologically active HA. Here, we demonstrate that isotope dilution mass spectrometry (IDMS), a method capable of quantifying the absolute HA concentration without reference antigen use, can be further expanded by adding LTD followed with precipitation to selectively quantify the active HA. We test the LTD-IDMS assay on H7N9 vaccines stressed by low pH, raised temperature, or freeze/thaw cycles. This method, unlike SRID, has no requirement for strain-specific reference antigens or antibodies and can generate potency values that correlate with SRID. Thus, LTD-IDMS is a promising alternative in vitro potency assay for influenza vaccines to complement and potentially replace SRID in a pandemic when strain specific reagents may not be readily available.CC999999/Intramural CDC HHS/United States2019-10-01T00:00:00Z30194004PMC64136946705vault:3172

Non-animal replacement methods for veterinary vaccine potency testing: state of the science and future directions

NICEATM and ICCVAM convened an international workshop to review the state of the science of human and veterinary vaccine potency and safety testing methods and to identify opportunities to advance new and improved methods that can further reduce, refine, and replace animal use. Six topics were addressed in detail by speakers and workshop participants and are reported in a series of six reports. This workshop report, the second in the series, provides recommendations for current and future use of nonanimal methods and strategies for veterinary vaccine potency testing. Workshop participants recommended that future efforts to replace animal use give priority to vaccines (1) that use large numbers of animals per test and for which many serials are produced annually, (2) that involve significant animal pain and distress during procedures, (3) for which the functional protective antigen has been identified, (4) that involve foreign animal/zoonotic organisms that are dangerous to humans, and (5) that involve pathogens that can be easily spread to wildlife populations. Vaccines identified as the highest priorities were those for rabies, Leptospira spp., Clostridium spp., Erysipelas, foreign animal diseases (FAD), poultry diseases, and fish diseases. Further research on the identification, purification, and characterization of vaccine protective antigens in veterinary vaccines was also identified as a priority. Workshop participants recommended priority research, development, and validation activities to address critical knowledge and data gaps, including opportunities to apply new science and technology. Recommendations included (1) investigations into the relative impact of various adjuvants on antigen quantification assays, (2) investigations into extraction methods that could be used for vaccines containing adjuvants that can interfere with antigen assays, and (3) review of the current status of rabies and tetanus human vaccine in vitro potency methods for their potential application to the corresponding veterinary vaccines. Workshop participants recommended enhanced international harmonization and cooperation and closer collaborations between human and veterinary researchers to expedite progress. Implementation of the workshop recommendations is expected to advance alternative in vitro methods for veterinary vaccine potency testing that will benefit animal welfare and replace animal use while ensuring continued protection of human and animal health

Safety and potency testing of veterinary vaccines

Prior to licensing of veterinary vaccines, it is essential to demonstrate that the use of the product is safe (e.g., use of the product will not have unexpected or undesirable effects on animals exposed to the agent or on the environment) and potent (e.g., produces the desired result). The projects described in this dissertation demonstrate research directed toward the development and improvement of safety and potency testing of veterinary vaccines from a regulatory perspective;In the first study, recombination between vaccine strains of pseudorabies virus (PRV) resulting in the creation of strains with undesirable virulence and antigenic combinations was demonstrated. Awareness of the potential for creating virulent strains with the antigenic profile of vaccine strains has resulted in more careful use of vaccines and may have decreased disruption of eradication programs due to misleading serologic data. In addition, regulatory policy now requires the assessment of recombination potential (and the consequences thereof) prior to licensing of modified-live vaccines using new strains of an agent;The second study involved safety assessment of live Salmonella sp. as vaccine vectors. This study demonstrated that the expression of inserted genes is dependent on the genetic background, resulting in the need to conduct safety testing of genetically engineered strains on the final construct;Using licensed erysipelas bacterins, the third study demonstrated that a strong immune response two weeks after vaccination did not necessarily predict sufficient immunity development to protect vaccinates from clinical signs of disease until market weight. Prior to these studies, a vaccinate was expected to develop a secondary response to exposure to the virulent agent that would protect the animal from disease. The results of this study demonstrate a need to prove durable immunity to market weight following label recommendations for all vaccines;The last two studies demonstrate the development of a monoclonal antibody to a protective immunogen of Erysipelothrix rhusiopathiae and an in vitro potency assay based on the monoclonal antibody. This assay is expected to replace animal potency testing of erysipelas bacterins, thus reducing costs, animal welfare concerns, and human exposure to the pathogen

Skeletal Muscle–Derived Cell Implantation for the Treatment of Fecal Incontinence: A Randomized, Placebo-Controlled Study

Background and Aims: Fecal incontinence (FI) improvement following injection of autologous skeletal muscle–derived cells has been previously suggested. This study aimed to test the efficacy and safety of said cells through a multicenter, placebo-controlled study, to determine an appropriate cell dose, and to delineate the target patient population that can most benefit from cell therapy. Methods: Patients experiencing FI for at least 6 months were randomized to receive a cell-free medium or low or high dose of cells. All patients received pelvic floor electrical stimulation before and after treatment. Incontinence episode frequency (IEF), FI quality of life, FI burden assessed on a visual analog scale, Wexner score, and parameters reflecting anorectal physiological function were all assessed for up to 12 months. Results: Cell therapy improved IEF, FI quality of life, and FI burden, reaching a preset level of statistical significance in IEF change compared with the control treatment. Post hoc exploratory analyses indicated that patients with limited FI duration and high IEF at baseline are most responsive to cells. Effects prevailed or increased in the high cell count group from 6 to 12 months but plateaued or diminished in the low cell count and control groups. Most physiological parameters remained unaltered. No unexpected adverse events were observed. Conclusions: Injection of a high dose of autologous skeletal muscle–derived cells followed by electrical stimulation significantly improved FI, particularly in patients with limited FI duration and high IEF at baseline, and could become a valuable tool for treatment of FI, subject to confirmatory phase 3 trial(s). (ClinicalTrialRegister.eu; EudraCT Number: 2010-021463-32)

Enriched protein screening of human bone marrow mesenchymal stromal cell secretions reveals MFAP5 and PENK as novel IL-10 modulators

The secreted proteins from a cell constitute a natural biologic library that can offer significant insight into human health and disease. Discovering new secreted proteins from cells is bounded by the limitations of traditional separation and detection tools to physically fractionate and analyze samples. Here, we present a new method to systematically identify bioactive cell-secreted proteins that circumvent traditional proteomic methods by first enriching for protein candidates by differential gene expression profiling. The bone marrow stromal cell secretome was analyzed using enriched gene expression datasets in combination with potency assay testing. Four proteins expressed by stromal cells with previously unknown anti-inflammatory properties were identified, two of which provided a significant survival benefit to mice challenged with lethal endotoxic shock. Greater than 85% of secreted factors were recaptured that were otherwise undetected by proteomic methods, and remarkable hit rates of 18% in vitro and 9% in vivo were achieved

Avaliação de reativos padrões para provas de Imunodifusão Radial. Controle in vitro de vacinas antirrábicas

The RID assay is one of the in vitro methods used for in-process control in the production of rabies vaccines for veterinary use. It has been shown to be very useful for determining antigen concentration in the final bulk product. The work presented in this paper, including the production and standardization of candidate standard reagents for use in the Radial Immunodiffusion Assay (RID) was carried out at the Pan American Institute for Food Protection and Zoonoses (INPPAZ/PAHO/WHO). The study was completed with the cooperation of the Faculty of Veterinary Sciences, National University of La Plata (NULP), Argentina, where the validation of the proposed standards and the quality control of samples from 28 different batches of rabies vaccines produced with Pasteur strain rabies virus (PV) in BHK cells were performed. The activity of the vaccines was determined by in vivo (NIH) and in vitro (RID)assays. The results of the candidate reagents for the reagent standardization tests showed stability, sensitivity and reproducibility. The Relative Potency the 1.2 between the problem vaccines and the reference vaccine was estimated by variance and regression analysis. The results of our validation study show that the INPPAZ (PAHO/WHO) is capable of producing and distributing the above-mentioned standard reagents, as well as of providing support for the incorporation of the RID technique (sensitive, rapid and inexpensive) to the laboratories that manufacture rabies vaccines in Latin America and the Caribbean.A prova de Imunodifusão Radial (IDR) é um método in vitro conveniente para determinar a concentração de antígenos no produto final como um todo, de vacinas anti-rábicas para uso veterinário. Os reativos padrões candidatos para uso na prova IDR, proposta para o controle de processo de vacinas de cultivo celular, elaboradas na América Latina e Caribe, foram produzidos e padronizados no Instituto Panamericano de Proteção de Alimentos e Zoonoses (INPPAZ). A validação dos padrões e o controle de qualidade de 28 lotes de vacinas anti-rábicas, de diferentes procedências, foram realizados na Faculdade de Ciências Veterinárias da Universidade de La Plata, Argentina (UNLP). Todas as vacinas foram elaboradas com virus rábico cepa Pasteur (PV) em células BHK e sua atividade foi determinada através de provas in vivo (NIH) e in vitro (IDR). Os resultados dos reativos, candidatos para as provas de padronização, demonstraram estabilidade, sensibilidade e reprodutibilidade. Por análise de variância e de regressão foi estimada a potência relativa de 1.2 entre as vacinas problemas e a vacina de referência. Os resultados deste estudo de validação indicam que o INPPAZ, está em condições de elaborar e distribuir os reativos padrões acima mencionados e apoiar a adoção da técnica de IDR (sensível, rápida, econômica) pelos laboratórios de produção de vacinas anti-rábicas da América Latina e Caribe

Evaluation of standard reagents for radial-immunodiffusion assays : In vitro control of rabies vaccines

The RID assay is one of the in vitro methods used for in-process control in the production of rabies vaccines for veterinary use. It has been shown to be very useful for determining antigen concentration in the final bulk product. The work presented in this paper, including the production and standardization of candidate standard reagents for use in the Radial Immunodiffusion Assay (RID) was carried out at the Pan American Institute for Food Protection and Zoonoses (INPPAZ/PAHO/WHO). The study was completed with the cooperation of the Faculty of Veterinary Sciences, National University of La Plata (NULP), Argentina, where the validation of the proposed standards and the quality control of samples from 28 different batches of rabies vaccines produced with Pasteur strain rabies virus (PV) in BHK cells were performed. The activity of the vaccines was determined by in vivo (NIH) and in vitro (RID)assays. The results of the candidate reagents for the reagent standardization tests showed stability, sensitivity and reproducibility. The Relative Potency the 1.2 between the problem vaccines and the reference vaccine was estimated by variance and regression analysis. The results of our validation study show that the INPPAZ (PAHO/WHO) is capable of producing and distributing the above-mentioned standard reagents, as well as of providing support for the incorporation of the RID technique (sensitive, rapid and inexpensive) to the laboratories that manufacture rabies vaccines in Latin America and the Caribbean.Facultad de Ciencias Veterinaria

Provjera kakvoće cjepiva za sezonsku gripu

The purpose of seasonal influenza vaccination is to prevent its spread. The vaccines contain strains of the influenza virus recommended and approved for a particular season. Just like any other medicinal product, all vaccines require marketing approval. Batches of approved vaccines are extensively tested by the manufacturers and additionally controlled by the approving authorities, which issue the quality control certificates. This article not only to describes the legal background of quality control, but also how control test results obtained by a Croatian official control laboratory are compared to manufacturer’s results. We have found that testing results can slightly differ depending on methods/analytical procedures used in different laboratories. This investigation has also shown how important it is to test finished medicinal products, independently of testing at intermediate stages, and how retesting by control authorities ensures that marketed vaccines meet quality standards.Za prevenciju i suzbijanje širenja gripe kao zarazne bolesti svake se godine provodi sezonsko cijepljenje cjepivima koja u svom sastavu sadržavju sojeve virusa influence preporučene i odobrene za tu sezonu. Da bi se mogla staviti u promet, sva cjepiva moraju od nadležnog tijela dobiti dozvolu za stavljanje u promet kao i drugi lijekovi. Puštanje u promet proizvedenih serija odobrenog cjepiva zahtijeva osim opsežnih ispitivanja od strane proizvođača i dodatnu kontrolu od strane nadležnog tijela koje izdaje Certifi kat o provedenoj provjeri kakvoće temeljem kojeg se cjepivo kao imunološki lijek može staviti u promet. Cilj ovog rada je prikazati ne samo pravnu osnovu provjere kakvoće već i kako su uspoređeni rezultati dobiveni ispitivanjem u hrvatskome kontrolnom laboratoriju u odnosu na rezultate ispitivanja proizvođača. Rezultati pokazuju da postoje manja neslaganja rezultata ispitivanja različitih laboratorija koja su u ovisnosti s korištenim metodama/analitičkim postupcima (sličan ili identičan analitički postupak). Rezultati također pokazuju važnost ispitivanja koja se provode na gotovom proizvodu, neovisno o ispitivanjima provedenim na međuproizvodima, kao i važnost retestiranja koje provodi nadležno tijelo u svrhu osiguranja da se na tržištu nalaze samo imunološki lijekovi koji udovoljavaju zahtjevima kakvoće