Pre-exposure with influenza A virus A/WSN/1933(H1N1) resulted in viral shedding reduction from pigs challenged with either swine H1N1 or H3N2 virus

The efficacy for direct immunofluorescence of a commercial conjugate for influenza A virus prepared against whole A/Udorn (H3NS) virus was studied. The conjugate was specific for influenza A virus, but its sensitivity varied depending upon the strain of influenza A tested. Nasopharyngeal aspirates collected from 25 patients during an outbreak of influenza were examined for viral antigen with the conjugates and inoculated onto monkey kidney (MK) cells for virus isolation. Fifteen patients had isolates for influenza A/USSR/90/77 (H1N1); nasopharyngeal secretions were fluorescent antibody positive in 12. Fluorescent antibody was copositive with culture in 11/15 patients (73.3%) and conegative in 9/10 (90%). The one fluorescent antibody-positive, culture-negative patient had negative serology for influenza A and the fluorescent antibody result was considered to be a false positive. At a 1:10 dilution, the conjugate stained nasopharyngeal and MK cells infected with A/USSR (H1N1) 2 to 3+, whereas cells infected with H3N2 virus stained 4+. A conjugate made specifically against the ribonucleoprotein antigen, which is universal to all influenza A strains, may improve the sensitivity of the direct immunofluorescent test.

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An in vitro network of intermolecular interactions between viral RNA segments of an avian H5N2 influenza A virus: comparison with a human H3N2 virus

Nucleic Acids Research ◽

10.1093/nar/gks1181 ◽

2012 ◽

Vol 41 (2) ◽

pp. 1241-1254 ◽

Cited By ~ 65

Author(s):

Cyrille Gavazzi ◽

Catherine Isel ◽

Emilie Fournier ◽

Vincent Moules ◽

Annie Cavalier ◽

...

Keyword(s):

Influenza A Virus ◽

Intermolecular Interactions ◽

Influenza A ◽

Viral Rna ◽

H3n2 Virus

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Influenza A virus PB1-F2 protein prolongs viral shedding in chickens lengthening the transmission window

Journal of General Virology ◽

10.1099/jgv.0.000584 ◽

2016 ◽

Vol 97 (10) ◽

pp. 2516-2527 ◽

Cited By ~ 22

Author(s):

Joe James ◽

Wendy Howard ◽

Munir Iqbal ◽

Venugopal K. Nair ◽

Wendy S. Barclay ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Viral Shedding ◽

Transmission Window

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Safety and Efficacy of Intravenous Zanamivir in Preventing Experimental Human Influenza A Virus Infection

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.7.1616 ◽

1999 ◽

Vol 43 (7) ◽

pp. 1616-1620 ◽

Cited By ~ 90

Author(s):

David P. Calfee ◽

Amy W. Peng ◽

Lindsey M. Cass ◽

Monica Lobo ◽

Frederick G. Hayden

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Controlled Study ◽

Nasal Discharge ◽

Upper Respiratory Tract ◽

Human Influenza ◽

Safety And Efficacy ◽

Viral Shedding ◽

Respiratory Tract Illness ◽

Double Blinded

ABSTRACT Zanamivir is a potent inhibitor of influenza A and B virus neuraminidases and is active topically in experimental and natural human influenza. We conducted this double-blinded, placebo-controlled study to evaluate the safety and efficacy of intravenously administered zanamivir. Susceptible volunteers were randomized to receive either saline or zanamivir (600 mg) intravenously twice daily for 5 days beginning 4 h prior to intranasal inoculation with ∼105 50% tissue culture infectious doses (TCID50) of influenza A/Texas/36/91 (H1N1) virus. Reductions in the frequency of viral shedding (0% versus 100% in placebo, P < 0.005) and seroconversion (14% versus 100% in placebo, P < 0.005) and decreases in viral titer areas under the curve (0 versus 11.6 [median] log10 TCID50 · day/ml in placebo,P < 0.005) were observed in the zanamivir group, as were reductions in fever (14% versus 88% in placebo,P < 0.05), upper respiratory tract illness (0% versus 100% in placebo, P < 0.005), total symptom scores (1 versus 44 [median] in placebo, P < 0.005), and nasal-discharge weight (3.9 g versus 17.5 g [median] in placebo, P < 0.005). Zanamivir was detectable in nasal lavage samples collected on days 2 and 4 (unadjusted median concentrations, 10.5 and 12.0 ng/ml of nasal wash, respectively). This study demonstrates that intravenously administered zanamivir is distributed to the respiratory mucosa and is protective against infection and illness following experimental human influenza A virus inoculation.

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Vaccines That Reduce Viral Shedding Do Not Prevent Transmission of H1N1 Pandemic 2009 Swine Influenza a Virus Infection to Unvaccinated Pigs

Journal of Virology ◽

10.1128/jvi.01787-20 ◽

2020 ◽

Author(s):

Helen E. Everett ◽

Pauline M. van Diemen ◽

Mario Aramouni ◽

Andrew Ramsay ◽

Vivien J. Coward ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Vaccine Coverage ◽

Swine Influenza Virus ◽

Swine Influenza ◽

Inhibitory Antibody ◽

Virus Shedding ◽

Virus Challenge ◽

Viral Shedding ◽

Swine Influenza A Virus

Swine influenza A virus (swIAV) infection causes substantial economic loss and disease burden in humans and animals. The 2009 pandemic H1N1 (pH1N1) influenza A virus is now endemic in both populations. In this study we evaluated the efficacy of different vaccines in reducing nasal shedding in pigs following pH1N1 virus challenge. We also assessed transmission from immunized and challenged to naive, directly in-contact pigs. Pigs were immunised with either adjuvanted, whole inactivated virus (WIV) vaccines or viral vectored (ChAdOx1 and MVA) vaccines expressing either the homologous or heterologous influenza A virus hemagglutinin (HA) glycoprotein as well as an influenza viral pseudotype (S-FLU) vaccine expressing heterologous HA. Only two vaccines containing homologous HA, which also induced high hemagglutination inhibitory antibody titers, significantly reduced virus shedding in challenged animals. Nevertheless, virus transmission from challenged to naive, in-contact animals occurred in all groups, although was delayed in groups of vaccinated animals with reduced virus shedding. IMPORTANCE This study was designed to determine whether vaccination of pigs with conventional, WIV or viral-vectored vaccines reduces pH1N1 swine influenza virus shedding following challenge and can prevent transmission to naive in-contact animals. Even when viral shedding was significantly reduced following challenge, infection was transmissible to susceptible co-housed recipients. This knowledge is important to inform disease surveillance and control strategies, and to determine the vaccine coverage required in a population, thereby defining disease moderation or herd protection. WIV or viral-vectored vaccines homologous to the challenge strain significantly reduced virus shedding from directly infected pigs, but vaccination did not completely prevent transmission to co-housed naive pigs.

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Recycling of H1N1 influenza A virus in man — a haemagglutinin antibody study

Journal of Hygiene ◽

10.1017/s0022172400029028 ◽

1993 ◽

Vol 90 (3) ◽

pp. 397-402 ◽

Cited By ~ 15

Author(s):

N. Masurel ◽

R. A. Heijtin

Keyword(s):

Hong Kong ◽

Influenza A Virus ◽

Human Population ◽

Influenza A ◽

H1n1 Virus ◽

H1n1 Influenza ◽

H3n2 Virus ◽

Influenza A H1n1 ◽

Antibody Titres

SUMMARYSera from people born between 1883 and 1930 and collected in 1977 were tested for the presence of HI antibodies to A/FM/1/47 (H1N1) virus and three recently (1977 and 1978) isolated influenza A-H1N1 viruses. The highest frequency of high-titred antibody to the four H1N1 viruses was detected in sera from people born in 1903–4, i.e. 42,54,38, and 22% had antibody against A/FM/1/47, A/Hong Kong/117/77, A/Brazil/11/78, and A/Fukushima/103/78 respectively. The birthdate groups 1896–1907 showed a higher percentage of HI antibody titres ≥18, ≥50, ≥100 or ≥1600 against the four H1N1 viruses than the birthdate groups 1907–30. This indicates the existence of an era, 1908–18, in which, apart from the H3N2 virus (1900–18), the H1N1 virus was epidemic among the human population.

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Assessment of the extent of variation in influenza A virus cytotoxic T-lymphocyte epitopes by using virus-specific CD8+ T-cell clones

Journal of General Virology ◽

10.1099/vir.0.82120-0 ◽

2007 ◽

Vol 88 (2) ◽

pp. 530-535 ◽

Cited By ~ 38

Author(s):

E. G. M. Berkhoff ◽

M. M. Geelhoed-Mieras ◽

R. A. M. Fouchier ◽

A. D. M. E. Osterhaus ◽

G. F. Rimmelzwaan

Keyword(s):

T Cell ◽

Influenza A Virus ◽

T Lymphocyte ◽

Influenza A ◽

Matrix Protein ◽

Cytotoxic T Lymphocyte ◽

H3n2 Virus ◽

Human Virus ◽

Ctl Epitopes ◽

Cell Clones

The influenza A virus nucleoprotein (NP) and matrix protein are major targets for human virus-specific cytotoxic T-lymphocyte (CTL) responses. Most of the CTL epitopes that have been identified so far are conserved. However, sequence variation in CTL epitopes of the NP has recently been demonstrated to be associated with escape from virus-specific CTLs. To assess the extent of variation in CTL epitopes during influenza A virus evolution, 304 CTL clones derived from six study subjects were obtained with specificity for an influenza A/H3N2 virus isolated in 1981. Subsequently, the frequency of the CTL clones that failed to recognize a more recent influenza virus strain isolated in 2003 was determined. In four of six study subjects, CTLs were found to be specific for variable epitopes, accounting for 2.6 % of all CTL clones. For some of these CTL clones, the minimal epitope and the residues responsible for abrogation of T-cell recognition were identified.

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High antiviral effect of TiO2·PL–DNA nanocomposites targeted to conservative regions of (−)RNA and (+)RNA of influenza A virus in cell culture

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.7.108 ◽

2016 ◽

Vol 7 ◽

pp. 1166-1173 ◽

Cited By ~ 11

Author(s):

Asya S Levina ◽

Marina N Repkova ◽

Elena V Bessudnova ◽

Ekaterina I Filippova ◽

Natalia A Mazurkova ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Mdck Cells ◽

Titanium Dioxide Nanoparticles ◽

Antiviral Effect ◽

H3n2 Virus ◽

Dna Fragments ◽

Efficient System ◽

Dna Fragment ◽

Viral Subtypes

Background: The development of new antiviral drugs based on nucleic acids is under scrutiny. An important problem in this aspect is to find the most vulnerable conservative regions in the viral genome as targets for the action of these agents. Another challenge is the development of an efficient system for their delivery into cells. To solve this problem, we proposed a TiO2·PL–DNA nanocomposite consisting of titanium dioxide nanoparticles and polylysine (PL)-containing oligonucleotides. Results: The TiO2·PL–DNA nanocomposites bearing the DNA fragments targeted to different conservative regions of (−)RNA and (+)RNA of segment 5 of influenza A virus (IAV) were studied for their antiviral activity in MDCK cells infected with the H1N1, H5N1, and H3N2 virus subtypes. Within the negative strand of each of the studied strains, the efficiency of DNA fragments increased in the direction of its 3’-end. Thus, the DNA fragment aimed at the 3’-noncoding region of (−)RNA was the most efficient and inhibited the reproduction of different IAV subtypes by 3–4 orders of magnitude. Although to a lesser extent, the DNA fragments targeted at the AUG region of (+)RNA and the corresponding region of (−)RNA were also active. For all studied viral subtypes, the nanocomposites bearing the DNA fragments targeted to (−)RNA appeared to be more efficient than those containing fragments aimed at the corresponding (+)RNA regions. Conclusion: The proposed TiO2·PL–DNA nanocomposites can be successfully used for highly efficient and site-specific inhibition of influenza A virus of different subtypes. Some patterns of localization of the most vulnerable regions in IAV segment 5 for the action of DNA-based drugs were found. The (−)RNA strand of IAV segment 5 appeared to be more sensitive as compared to (+)RNA.

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Protection against a Lethal Avian Influenza A Virus in a Mammalian System

Journal of Virology ◽

10.1128/jvi.73.2.1453-1459.1999 ◽

1999 ◽

Vol 73 (2) ◽

pp. 1453-1459 ◽

Cited By ~ 40

Author(s):

Janice M. Riberdy ◽

Kirsten J. Flynn ◽

Juergen Stech ◽

Robert G. Webster ◽

John D. Altman ◽

...

Keyword(s):

T Cell ◽

Avian Influenza ◽

Influenza A Virus ◽

Influenza A ◽

Influenza Pandemic ◽

Immune Memory ◽

H3n2 Virus ◽

Influenza A Viruses ◽

Cell Responses ◽

Avian Influenza A Virus

ABSTRACT The question of how best to protect the human population against a potential influenza pandemic has been raised by the recent outbreak caused by an avian H5N1 virus in Hong Kong. The likely strategy would be to vaccinate with a less virulent, laboratory-adapted H5N1 strain isolated previously from birds. Little attention has been given, however, to dissecting the consequences of sequential exposure to serologically related influenza A viruses using contemporary immunology techniques. Such experiments with the H5N1 viruses are limited by the potential risk to humans. An extremely virulent H3N8 avian influenza A virus has been used to infect both immunoglobulin-expressing (Ig+/+) and Ig−/− mice primed previously with a laboratory-adapted H3N2 virus. The cross-reactive antibody response was very protective, while the recall of CD8+ T-cell memory in the Ig−/− mice provided some small measure of resistance to a low-dose H3N8 challenge. The H3N8 virus also replicated in the respiratory tracts of the H3N2-primed Ig+/+ mice, generating secondary CD8+ and CD4+ T-cell responses that may contribute to recovery. The results indicate that the various components of immune memory operate together to provide optimal protection, and they support the idea that related viruses of nonhuman origin can be used as vaccines.

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Analysis of influenza A virus reinfection in children in Japan during 1983–91

Epidemiology and Infection ◽

10.1017/s0950268800058751 ◽

1995 ◽

Vol 115 (3) ◽

pp. 591-601 ◽

Cited By ~ 5

Author(s):

S. Nakajima ◽

F. Nishikawa ◽

K. Nakamura ◽

K. Nakajima

Keyword(s):

Amino Acid ◽

Influenza A Virus ◽

Influenza A ◽

Haemagglutination Inhibition ◽

Influenza Viruses ◽

Antigenic Drift ◽

H3n2 Virus ◽

Influenza B ◽

Influenza A H1n1 ◽

Influenza H3n2

SummaryThe epidemiology of influenza A in Japan was studied during 1979–91 and viruses isolated from reinfections during 1983–91 were analysed, Of 2963 influenza viruses isolated during this period, 922 and 1006 were influenza A(H1N1) and A(H3N2) viruses respectively; the others were influenza B viruses. Influenza A(H1N1) and A(H3N2) caused 5 and 6 epidemics respectively, most accompanied by antigenic drift. Seventeen reinfections with H1N1 and 17 with H3N2 were detected during our study. The primary and reinfection strains isolated from 7 H1N1 and 10 H3N2 cases were studied by haemagglutination-inhibition, and amino acid and nucleotide sequences of the HA1 region of the haemagglutinin. Most of the primary and reinfection strains were antigenically and genetically similar to the epidemic viruses circulating at that time. However, in 4 out of 10 cases of reinfection with influenza H3N2 virus, reinfection strains were genetically different from the epidemic viruses.

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