Establishment of a national network of validated and qualified laboratories for neutralizing anti-vaccinia antibodies titration

Poirier, Bertrand; Leparc-Goffart, Isabelle; Crance, Jean‐Marc; Fleury, Hervé; Garín, Daniel; Gut, Jean‐Pierre; Tissier, Marie-Hélène; Fuchs, Florence

doi:10.1016/j.biologicals.2005.06.006

Cited by 2 publications

(3 citation statements)

References 4 publications

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“…Where death occurred, the number of animals that succumbed is indicated as a ratio of the six animals in the group. within the range of the titers found in human subjects vaccinated against smallpox (39,58). The Nab titers with all of the deletion mutants were similar to those with the parental Lister strain and the clonal VACV-107 isolate (P Ͼ 0.05).…”

Section: Resultssupporting

confidence: 61%

“…Vaccinated mice were anesthetized with pentobarbital and bled by intracardiac puncture, and VACV-neutralizing antibodies in serum samples were titrated according to a previously described method (39) validated in four laboratories (58). Briefly, serum samples were first incubated at 56°C for 30 min to inactivate complement and then subjected to serial 2-fold dilutions in phosphate-buffered saline (PBS).…”

Section: Methodsmentioning

confidence: 99%

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Deletion of Major Nonessential Genomic Regions in the Vaccinia Virus Lister Strain Enhances Attenuation without Altering Vaccine Efficacy in Mice

Dimier

Ferrier-Rembert

Pradeau‐Aubreton

et al. 2011

J Virol

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The vaccinia virus (VACV) Lister strain was one of the vaccine strains that enabled smallpox eradication. Although the strain is most often harmless, there have been numerous incidents of mild to life-threatening accidents with this strain and others. In an attempt to further attenuate the Lister strain, we investigated the role of 5 genomic regions known to be deleted in the modified VACV Ankara (MVA) genome in virulence in immunodeficient mice, immunogenicity in immunocompetent mice, and vaccine efficacy in a cowpox virus challenge model. Lister mutants were constructed so as to delete each of the 5 regions or various combinations of these regions. All of the mutants replicated efficiently in tissue culture except region I mutants, which multiplied more poorly in human cells than the parental strain. Mutants with single deletions were not attenuated or only moderately so in athymic nude mice. Mutants with multiple deletions were more highly attenuated than those with single deletions. Deleting regions II, III, and V together resulted in total attenuation for nude mice and partial attenuation for SCID mice. In immunocompetent mice, the Lister deletion mutants induced VACV specific humoral responses equivalent to those of the parental strain but in some cases lower cell-mediated immune responses. All of the highly attenuated mutants protected mice from a severe cowpox virus challenge at low vaccine doses. The data suggest that several of the Lister mutants combining multiple deletions could be used in smallpox vaccination or as live virus vectors at doses equivalent to those used for the traditional vaccine while displaying increased safety.Vaccinia virus (VACV) has displayed extraordinary efficacy as a live attenuated vaccine since it has enabled the eradication of smallpox, one of the most deadly infectious diseases for mankind. Although smallpox vaccination is no longer routinely employed, some countries continue to vaccinate selected populations because of the fear of biological warfare or bioterrorism. During the course of their use, the smallpox vaccines were responsible for numerous vaccine-associated accidents like eczema vaccinatum and progressive vaccinia in individuals with immune deficiencies or skin disorders. Encephalitis was also long recognized as a very serious vaccine-related risk with an unknown predisposition (35), and vaccine-induced myopericarditis has been documented as an adverse event (27, 32). It is therefore not surprising that a good deal of research has been devoted to designing strategies that reduce the risks associated with smallpox vaccination (52). Further attenuation of the smallpox vaccine has also been sought because VACV is an attractive live virus vector for vaccination against infectious diseases and displays promising activity as a vector for prophylaxis and therapy of cancer (25).Modified vaccinia virus Ankara (MVA) was one of the first VACV strains shown to be highly attenuated in small-animal models and safe in human trials (42,66). MVA was isolated during the 1960s fr...

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Section: Resultssupporting

confidence: 61%

Section: Methodsmentioning

confidence: 99%

Deletion of Major Nonessential Genomic Regions in the Vaccinia Virus Lister Strain Enhances Attenuation without Altering Vaccine Efficacy in Mice

Dimier

Ferrier-Rembert

Pradeau‐Aubreton

et al. 2011

J Virol

Self Cite

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“…Although proficiency testing programs for neutralizing antibody assays against other pathogens exist, this is the first program available for the evaluation and documentation of assay equivalency for laboratories measuring neutralizing antibody responses against HIV-1 (Poirier et al, 2005). This is an important program for those laboratories that operate in a GCLP environment.…”

Section: Discussionmentioning

confidence: 99%

Development and implementation of an international proficiency testing program for a neutralizing antibody assay for HIV-1 in TZM-bl cells

Todd

Greene

et al. 2012

Journal of Immunological Methods

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Recent advances in assay technology have led to major improvements in how HIV-1 neutralizing antibodies are measured. A luciferase reporter gene assay performed in TZM-bl (JC53bl-13) cells has been optimized and validated. Because this assay has been adopted by multiple laboratories worldwide, an external proficiency testing program was developed to ensure data equivalency across laboratories performing this neutralizing antibody assay for HIV/AIDS vaccine clinical trials. The program was optimized by conducting three independent rounds of testing, with an increased level of stringency from the first to third round. Results from the participating domestic and international laboratories improved each round as factors that contributed to inter-assay variability were identified and minimized. Key contributors to increased agreement were experience among laboratories and standardization of reagents. A statistical qualification rule was developed using a simulation procedure based on the three optimization rounds of testing, where a laboratory qualifies if at least 25 of the 30 ID50 values lie within the acceptance ranges. This ensures no more than a 20% risk that a participating laboratory fails to qualify when it should, as defined by the simulation procedure. Five experienced reference laboratories were identified and tested a series of standardized reagents to derive the acceptance ranges for pass–fail criteria. This Standardized Proficiency Testing Program is the first available for the evaluation and documentation of assay equivalency for laboratories performing HIV-1 neutralizing antibody assays and may provide guidance for the development of future proficiency testing programs for other assay platforms.

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Establishment of a national network of validated and qualified laboratories for neutralizing anti-vaccinia antibodies titration

Cited by 2 publications

References 4 publications

Deletion of Major Nonessential Genomic Regions in the Vaccinia Virus Lister Strain Enhances Attenuation without Altering Vaccine Efficacy in Mice

Deletion of Major Nonessential Genomic Regions in the Vaccinia Virus Lister Strain Enhances Attenuation without Altering Vaccine Efficacy in Mice

Development and implementation of an international proficiency testing program for a neutralizing antibody assay for HIV-1 in TZM-bl cells

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