Plaque reduction neutralization test for measles antibodies: Description of a standardised laboratory method for use in immunogenicity studies of aerosol vaccination
Centre for Infections, Health Protection Agency, London NW9 5EQ, UK. Vaccine
(Impact Factor: 3.62).
01/2008; 26(1):59-66. DOI: 10.1016/j.vaccine.2007.10.046
Clinical trials of measles vaccination administered as aerosol are planned with the aim of obtaining licensure. Measles antibody levels will be measured using the plaque reduction neutralization test (PRNT) to assess antibody responses as a surrogate marker of efficacy.
A working group examined laboratory protocols for measles PRNT in use at three reference centres and agreed to a standardised procedure, which was subsequently validated.
Assay validation showed quantitative results varied approximately threefold both within and between assays. The lower limit of detection was approximately 20milliInternational Units/mL.
A standardised laboratory protocol for measles PRNT was established and validated for use in clinical trials of aerosolized measles vaccines.
Available from: Jennifer Chan
- "Plaque reduction assay modified from (19) was used to analyze SFV neutralization. Twenty-four well tissue culture plates were seeded with 1.5 × 105 Vero cells/well and incubated overnight at 37°C in a humidified atmosphere with 5% CO2. "
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ABSTRACT: Many currently available inactivated vaccines require "adjuvants" to maximize the protective immune responses generated against the antigens of interest. Recent studies in mice with gamma-irradiated influenza A virus (γ-FLU) have shown its superior efficacy compared to other forms of inactivated FLU vaccines and its ability to induce both potent interferon type-I (IFN-I) responses and the IFN-I-associated partial lymphocyte activation. Commonly, IFN-I responses induced by adjuvants, combined in vaccine preparations, have been shown to effectively enhance the immunogenicity of the antigens of interest. Therefore, we investigated the potential adjuvant activity of γ-FLU and the possible effect on antibody responses against co-administrated antigens, using gamma-irradiated Semliki Forest virus (γ-SFV) as the experimental vaccine in mice. Our data show that co-vaccination with γ-FLU and γ-SFV resulted in enhanced SFV-specific antibody responses in terms of increased titers by sixfold and greater neutralization efficacy, when compared to vaccination with γ-SFV alone. This study provides promising evidence related to the possible use of γ-FLU as an adjuvant to poorly immunogenic vaccines without compromising the vaccine efficacy of γ-FLU.
Frontiers in Immunology 06/2014; 5:267. DOI:10.3389/fimmu.2014.00267
Available from: Jose-Luis Diaz-Ortega
- "The serum was transferred to cryotubes and stored at −20 • C until testing for antibodies at the Laboratory of Viral Vaccines of the INSP. Measles antibodies were evaluated by the plaque reduction neutralization test (PRN) in Vero cells . Antibodies against rubella and mumps were evaluated by immune-enzymatic assays with commercial kits  . "
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ABSTRACT: Importance: Aerosol immunization may be a useful tool to reach and sustain the elimination of measles, rubella, and congenital rubella syndrome. We compared booster seroresponses to aerosolized or injected MMR vaccines containing different strains of measles (Attenuvax or Edmonston-Zagreb) and mumps (Jeryl-Lynn or Leningrad-Zagreb). Objective: To assess the safety and immunogenicity of two MMR: Vaccines administered by aerosol. Methods: A randomized and controlled clinical trial was conducted to evaluate the safety and booster responses to the MMR SII (Serum Institute of India) and MMR II (Merck Sharp & Dhome) vaccines, both of which were administered by aerosol (ae) or injection (inj) to Mexican children aged 6-7 years in elementary schools. The seroresponses were evaluated by PRN (measles) and ELISA (rubella and mumps). Adverse events were followed-up for 28 days after the immunization. Results: Two hundred and fifty-three of 260 children completed the one-month follow-up. All participants reached protective seropositivity for measles and rubella after immunization, and 98.3 to 100% reached protective seropositivity for mumps (p= 0.552). The proportions of the seroresponses (a 2-fold rise from the baseline antibody titers) to measles were 38.3% for MMR SII (ae), 31.3% for MMR II (ae), 37.5% for MMR SII (inj), and 44.6% for MMR II (inj) (p= 0.483). The seroresponses for rubella were 26.7% for MMR SII (ae), 31.3% for MMR II (ae), 46.9% for MMR SII (inj), and 40.0% for MMR II (inj) (p= 0.086). The seroresponse to mumps were 31.7% for MMR SII (ae), 25.0% for MMR II (ae), 48.4% for MMR SII (inj), and 53.9% for MMR II (inj) (p= 0.002). The difference in the seroresponse of a 4-fold rise from the baseline antibody titers was not statistically significant. Only mild adverse events were noted. Conclusion: Aerosolized vaccines were as safe and as immunogenic as injected vaccines. Protocol registration: CMN 2010-005 (National Regulatory Authority).
Vaccine 05/2014; 32(29). DOI:10.1016/j.vaccine.2014.04.031 · 3.62 Impact Factor
Available from: Wenbo Xu
- "The titers of isolated virus were measured using CPE microtitration assays and were expressed as the 50% tissue culture infective dose (TCID50) per mL according to the Kärber formula . "
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ABSTRACT: Enterovirus 96 (EV-C96) is a newly described serotype within the enterovirus C (EV-C) species, and its biological and pathological characters are largely unknown. In this study, we sequenced the whole genome of a novel EV-C96 strain that was isolated in 2011 from a patient with acute flaccid paralysis (AFP) in Guangdong province, China and characterized the properties of its infection. Sequence analysis revealed the close relationship between the EV-C96 strains isolated from the Guangdong and Shandong provinces of China, and suggested that recombination events occurred both between these EV-C96 strains and with other EV-C viruses. Moreover, the virus replication kinetics showed EV-C96 Guangdong strain replicated at a high rate in RD cells and presented a different cell tropism to other strains isolated from Shandong recently. These findings gave further insight into the evolutionary processes and extensive biodiversity of EV-C96.
PLoS ONE 01/2014; 9(1):e86877. DOI:10.1371/journal.pone.0086877 · 3.23 Impact Factor
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