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1.
Jpn J Infect Dis ; 77(2): 105-111, 2024 Mar 21.
Article in English | MEDLINE | ID: mdl-38030271

ABSTRACT

Potency tests for influenza vaccines are currently performed using a single-radial immunodiffusion (SRID) assay, which requires a reference antigen and anti-hemagglutinin (HA) serum as reference reagents. Reagents must be newly prepared each time a strain used for vaccine production is modified. Therefore, establishing reference reagents of consistent quality is crucial for conducting vaccine potency tests accurately and precisely. Here, we established reference reagents for the SRID assay to conduct lot release tests of quadrivalent influenza vaccines in Japan during the 2022/23 influenza season. The potency of reference antigens during storage was confirmed. Furthermore, we evaluated the cross-reactivity of each antiserum raised against the HA protein of the 2 lineages of influenza B virus toward different lineages of influenza B virus antigens to select a suitable procedure for the SRID assay for accurate measurement. Finally, the intralaboratory reproducibility of the SRID assay using the established reference reagents was validated, and the SRID reagents had sufficient consistent quality, comparable to that of the reagents used for testing vaccines during previous influenza seasons. Our study contributes to the quality control of influenza vaccines.


Subject(s)
Influenza Vaccines , Influenza, Human , Humans , Influenza, Human/prevention & control , Seasons , Japan , Reproducibility of Results , Hemagglutinin Glycoproteins, Influenza Virus , Immunodiffusion/methods
2.
Influenza Other Respir Viruses ; 17(2): e13093, 2023 02.
Article in English | MEDLINE | ID: mdl-36824396

ABSTRACT

Background: The antigenicity of SARS-CoV-2 is a critical issue for the effectiveness of the vaccine, and thus, it should be phenotypically evaluated by serological assays as new field isolates emerge. The hemagglutination/hemagglutination inhibition (HA/HI) tests are well known as a representative method for antigenic analysis of influenza viruses, but SARS-CoV-2 does not agglutinate human or guinea pig red blood cells. Therefore, the antigenic analysis requires complicated cell-based assays using special equipment such as plate reader or ELISPOT analyzer. Methods: Based on the HA/HI tests for influenza viruses, we developed the particle agglutination/particle agglutination inhibition (PA/PAI) test to easily and rapidly quantify the virus and antibody using human angiotensin-converting enzyme 2 (hACE2)-bound latex beads. The virus titers were determined by mixing the beads and the virus from culture supernatant, settling it overnight, and then observing the sedimentation/agglutination pattern (PA test). The neutralization antibody titers were determined by mixing virus-infected hamster antisera in addition to the beads and virus (PAI test). Results: The PA titer was positively correlated with the plaque-forming units. The PAI titer using the hamster antisera clearly revealed the antigenic difference between the omicron and previous variants. The antigenic differences were supported by the results shown in other methods. Conclusions: The PAI test is an easy and rapid method to analyze the antigenicity of SARS-CoV-2.


Subject(s)
COVID-19 , Orthomyxoviridae , Animals , Humans , Guinea Pigs , SARS-CoV-2 , Hemagglutination Inhibition Tests , Agglutination , Immune Sera , Hemagglutinin Glycoproteins, Influenza Virus
3.
PLoS One ; 18(1): e0280811, 2023.
Article in English | MEDLINE | ID: mdl-36662890

ABSTRACT

Manufactured influenza vaccines have to contain a defined amount of hemagglutinin (HA) antigen. Therefore, vaccine viruses with a high HA antigen yield (HAY) are preferable for manufacturing vaccines, particularly vaccines in response to a pandemic, when vaccines need to be rapidly produced. However, the viral properties associated with a high HAY have not yet been fully clarified. To identify the HAY-associated traits, we first propagated 26 H5 candidate vaccine viruses (CVVs) in eggs, which were previously developed based on genetic reassortment methods using master viruses, to determine their total protein yield (TPY), ratio of HA to total viral protein (%-HA content) and HAY. The results revealed that the HAY was correlated with the TPY but not with the %-HA content. We further found that altering the sequences of the 3' noncoding region of HA vRNA or replacing the master virus improved the HAYs and TPYs of the low-HAY CVVs to approximately double the values of the original CVVs but did not change the %-HA content, which a previous study suggested was associated with the HAY. Analyses based on real-time PCR assays and scanning electron microscopy revealed that the virus samples with an improved HAY contained more copies of the virus genome and viral particles than the original samples. The results suggest that an improvement in virus growth (i.e., an increase in the amount of viral particles) leads to an increase in the TPY and thus in the HAY, regardless of the %-HA content. The approximately twofold increase in the HAY shown in this study may not appear to represent a large improvement, but the impact will be significant given the millions of chicken eggs used to produce vaccines. These findings will be informative for developing high-HAY vaccine viruses.


Subject(s)
Influenza Vaccines , Orthomyxoviridae , Animals , Hemagglutinins/genetics , Hemagglutinin Glycoproteins, Influenza Virus , Chickens , Antibodies, Viral
4.
Vaccine ; 40(31): 4231-4241, 2022 07 29.
Article in English | MEDLINE | ID: mdl-35691872

ABSTRACT

The vaccine S-268019-b is a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S)-protein vaccine consisting of full-length recombinant SARS-CoV-2 S-protein (S-910823) as antigen, mixed with the squalene-based adjuvant A-910823. The current study evaluated the immunogenicity of S-268019-b using various doses of S-910823 and its vaccine efficacy against SARS-CoV-2 challenge in cynomolgus monkeys. The different doses of S-910823 combined with A-910823 were intramuscularly administered twice at a 3-week interval. Two weeks after the second dosing, dose-dependent humoral immune responses were observed with neutralizing antibody titers being comparable to that of human convalescent plasma. Pseudoviruses harboring S proteins from Beta and Gamma SARS-CoV-2 variants displayed approximately 3- to 4-fold reduced sensitivity to neutralizing antibodies induced after two vaccine doses compared with that against ancestral viruses, whereas neutralizing antibody titers were reduced >14-fold against the Omicron variant. Cellular immunity was also induced with a relative Th1 polarized response. No adverse clinical signs or weight loss associated with the vaccine were observed, suggesting safety of the vaccine in cynomolgus monkeys. Immunization with 10 µg of S-910823 with A-910823 demonstrated protective efficacy against SARS-CoV-2 challenge according to genomic and subgenomic viral RNA transcript levels in nasopharyngeal, throat, and rectal swab specimens. Pathological analysis revealed no detectable vaccine-dependent enhancement of disease in the lungs of challenged vaccinated monkeys. The current findings provide fundamental information regarding vaccine doses for human trials and support the development of S-268019-b as a safe and effective vaccine for controlling the current pandemic, as well as general protection against SARS-CoV-2 moving forward.


Subject(s)
COVID-19 , Viral Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19/therapy , Immunization, Passive , Immunogenicity, Vaccine , Macaca fascicularis , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , COVID-19 Serotherapy
5.
Jpn J Infect Dis ; 75(4): 398-402, 2022 Jul 22.
Article in English | MEDLINE | ID: mdl-34980710

ABSTRACT

The circulation of avian influenza A viruses in poultry is a public health concern due to the potential transmissibility and severity of these viral infections. Monitoring the susceptibility of these viruses to antivirals is important for developing measures to strengthen the level of preparedness against influenza pandemics. However, drug susceptibility information on these viruses is limited. Here, we determined the susceptibilities of avian influenza A(H5N1), A(H5N2), A(H5N8), A(H7N7), A(H7N9), A(H9N1), and A(H9N2) viruses isolated in Japan to the antivirals approved for use there: an M2 inhibitor (amantadine), neuraminidase inhibitors (oseltamivir, peramivir, zanamivir, and laninamivir) and RNA polymerase inhibitors (baloxavir and favipiravir). Genotypic methods that detect amino acid substitutions associated with antiviral resistance and phenotypic methods that assess phenotypic viral susceptibility to drugs have revealed that these avian influenza A viruses are susceptible to neuraminidase and RNA polymerase inhibitors. These results suggest that neuraminidase and RNA polymerase inhibitors currently approved in Japan could be a treatment option against influenza A virus infections in humans.


Subject(s)
Drug Resistance, Viral , Influenza in Birds , Influenza, Human , Animals , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , DNA-Directed RNA Polymerases , Drug Resistance, Viral/genetics , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Humans , Influenza A Virus, H5N1 Subtype/drug effects , Influenza A Virus, H5N2 Subtype/drug effects , Influenza A Virus, H7N7 Subtype/drug effects , Influenza A Virus, H7N9 Subtype/drug effects , Influenza A Virus, H9N2 Subtype/drug effects , Influenza in Birds/epidemiology , Influenza in Birds/virology , Influenza, Human/epidemiology , Influenza, Human/virology , Japan/epidemiology , Neuraminidase/genetics , Neuraminidase/metabolism , Oseltamivir/pharmacology , Oseltamivir/therapeutic use , Poultry
6.
J Vet Med Sci ; 81(3): 444-448, 2019 Mar 20.
Article in English | MEDLINE | ID: mdl-30674734

ABSTRACT

A new reassortant H7N3 avian influenza virus (AIV) was isolated from a duck meat product that was illegally taken on board a passenger flight from China to Japan in March 2018. Sequencing analysis revealed that the H7N3 isolate, A/duck/Japan/AQ-HE30-1/2018 (Dk/HE30-1) (H7N3), was a reassortant highly pathogenic avian influenza virus (HPAIV) that contained the haemagglutinin (HA) gene of Chinese H7N9 HPAIV. Dk/HE30-1 (H7N3) possessed a novel polybasic sequence motif PEVPKRRRTAR/GLF at the HA cleavage site that has never previously been reported in H7 HPAIVs. The HA antigenicity of Dk/HE30-1 (H7N3) slightly differed from that of H7N9 HPAIVs previously reported. These findings will help further our knowledge of the circulation and genetic evolution of emerging AIVs in endemic areas.


Subject(s)
Influenza A Virus, H7N3 Subtype/isolation & purification , Meat Products/virology , Travel , Aircraft , Animals , Ducks , Food Contamination , Influenza A Virus, H7N3 Subtype/genetics , Influenza A Virus, H7N3 Subtype/pathogenicity , Japan , Phylogeny , Reassortant Viruses , Virulence
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