Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-29 (of 29 Records) |
Query Trace: Pearce MB[original query] |
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Pathogenesis and transmission of genetically diverse swine-origin H3N2v influenza A viruses from multiple lineages isolated in the United States, 2011-2016.
Sun X , Pulit-Penaloza JA , Belser JA , Pappas C , Pearce MB , Brock N , Zeng H , Creager HM , Zanders N , Jang Y , Tumpey TM , Davis T , Maines TR . J Virol 2018 92 (16) While several swine-origin influenza A H3N2 variant (H3N2v) viruses isolated from humans prior to 2011 have been previously characterized for their virulence and transmissibility in ferrets, recent genetic and antigenic divergence of H3N2v viruses warrants an updated assessment of their pandemic potential. Here, four contemporary H3N2v viruses isolated during 2011-2016 were evaluated for their replicative ability in both in vitro and in vivo mammalian models, as well as their transmissibility among ferrets. We found that all four H3N2v viruses possessed similar or enhanced replication capacity in a human bronchial epithelium cell line (Calu-3) compared to a human seasonal influenza virus, suggestive of strong fitness in human respiratory tract cells. The majority of H3N2v viruses examined in our study were mildly virulent in mice and capable of replicating in mouse lungs with different degrees of efficiency. In ferrets, all four H3N2v viruses caused moderate morbidity and exhibited comparable titers in the upper respiratory tract, but only 2 of the 4 viruses replicated in the lower respiratory tract in this model. Furthermore, despite efficient transmission among cohoused ferrets, recently isolated H3N2v viruses displayed considerable variance in their ability to transmit by respiratory droplets. The lack of a full understanding of the molecular correlates of virulence and transmission underscores the need for close genotypic and phenotypic monitoring of H3N2v viruses and the importance of continued surveillance to improve pandemic preparedness.Importance: Swine-origin influenza viruses of the H3N2 subtype, with the HA and NA derived from historic human seasonal influenza viruses, continue to cross species barriers and cause human infections, posing an indelible threat to public health. To help us better understand the potential risk associated with swine-origin H3N2v viruses that emerged in the U.S between 2011-2016 influenza seasons, we use both in vitro and in vivo models to characterize the ability of these viruses to replicate, caused disease, and transmit in mammalian hosts. The efficient respiratory droplet transmission exhibited by some of the H3N2v viruses in the ferret model combined with the existing evidence of low immunity against such viruses in young children and older adults highlights their pandemic potential. Extensive surveillance and risk assessment of H3N2v viruses should continue to be an essential component of our pandemic preparedness strategy. |
Pathogenicity testing of influenza candidate vaccine viruses in the ferret model
Belser JA , Johnson A , Pulit-Penaloza JA , Pappas C , Pearce MB , Tzeng WP , Hossain MJ , Ridenour C , Wang L , Chen LM , Wentworth DE , Katz JM , Maines TR , Tumpey TM . Virology 2017 511 135-141 The development of influenza candidate vaccine viruses (CVVs) for pre-pandemic vaccine production represents a critical step in pandemic preparedness. The multiple subtypes and clades of avian or swine origin influenza viruses circulating world-wide at any one time necessitates the continuous generation of CVVs to provide an advanced starting point should a novel zoonotic virus cross the species barrier and cause a pandemic. Furthermore, the evolution and diversity of novel influenza viruses that cause zoonotic infections requires ongoing monitoring and surveillance, and, when a lack of antigenic match between circulating viruses and available CVVs is identified, the production of new CVVs. Pandemic guidelines developed by the WHO Global Influenza Program govern the design and preparation of reverse genetics-derived CVVs, which must undergo numerous safety and quality tests prior to human use. Confirmation of reassortant CVV attenuation of virulence in ferrets relative to wild-type virus represents one of these critical steps, yet there is a paucity of information available regarding the relative degree of attenuation achieved by WHO-recommended CVVs developed against novel viruses with pandemic potential. To better understand the degree of CVV attenuation in the ferret model, we examined the relative virulence of six A/Puerto Rico/8/1934-based CVVs encompassing five different influenza A subtypes (H2N3, H5N1, H5N2, H5N8, and H7N9) compared with the respective wild-type virus in ferrets. Despite varied virulence of wild-type viruses in the ferret, all CVVs examined showed reductions in morbidity and viral shedding in upper respiratory tract tissues. Furthermore, unlike the wild-type counterparts, none of the CVVs spread to extrapulmonary tissues during the acute phase of infection. While the magnitude of virus attenuation varied between virus subtypes, collectively we show the reliable and reproducible attenuation of CVVs that have the A/Puerto Rico/9/1934 backbone in a mammalian model. |
Neuraminidase-based recombinant virus-like particles protect against lethal avian influenza A(H5N1) virus infection in ferrets.
Smith GE , Sun X , Bai Y , Liu YV , Massare MJ , Pearce MB , Belser JA , Maines TR , Creager HM , Glenn GM , Flyer D , Pushko P , Levine MZ , Tumpey TM . Virology 2017 509 90-97 Avian influenza A (H5N1) viruses represent a growing threat for an influenza pandemic. The presence of widespread avian influenza virus infections further emphasizes the need for vaccine strategies for control of pre-pandemic H5N1 and other avian influenza subtypes. Influenza neuraminidase (NA) vaccines represent a potential strategy for improving vaccines against avian influenza H5N1 viruses. To evaluate a strategy for NA vaccination, we generated a recombinant influenza virus-like particle (VLP) vaccine comprised of the NA protein of A/Indonesia/05/2005 (H5N1) virus. Ferrets vaccinated with influenza N1 NA VLPs elicited high-titer serum NA-inhibition (NI) antibody titers and were protected from lethal challenge with A/Indonesia/05/2005 virus. Moreover, N1-immune ferrets shed less infectious virus than similarly challenged control animals. In contrast, ferrets administered control N2 NA VLPs were not protected against H5N1 virus challenge. These results provide support for continued development of NA-based vaccines against influenza H5N1 viruses. |
Preexisting immunity not frailty phenotype predicts influenza post vaccination titers among older veterans
Van Epps P , Tumpey T , Pearce MB , Golding H , Higgins P , Hornick T , Burant C , Wilson BM , Banks R , Gravenstein S , Canaday DH . Clin Vaccine Immunol 2017 24 (3) Both preexisting immunity to influenza and age have been shown to be a correlate of influenza vaccine response. Frailty, an indicator of functional impairment in older adults, has also been shown in one study to predict lower influenza vaccine responses among non-veterans. In the current study we aimed to determine the association between frailty, preexisting immunity and immune response to influenza vaccine in older veterans. We analyzed 117 subjects (age range 62-95 years; median 81) divided into 3 cohorts based on the Fried frailty test: non-frail (NF: N=23; median age 68), pre-frail (PF: N=50; median age 80) and frail (F:N=44; median age 82) during the 2010-2011 and 11-12 influenza seasons. Subjects received the seasonal trivalent inactivated influenza vaccine and baseline and post-vaccination samples were obtained. Anti-influenza humoral immunity as measured by hemagglutinin inhibition (HI) and microneutralization (MN) assays were measured for influenza B, A(H1N1)pdm09 and A(H3N2) viruses. Post vaccination-titers to Influenza vaccine were not different between frail and NF subjects overall in this older subset of veterans. However, preexisting HI titers strongly correlated with post-vaccination titers among all functional status groups. When microneutralization titers are compared, the association between preexisting immunity and vaccine response varies by frailty status with the highest correlation observed in the NF subjects. In conclusion, preexisting immunity rather than frailty appear to predict post-influenza vaccine titer in this older veteran cohort. |
Enhanced virulence of clade 2.3.2.1 highly pathogenic avian influenza A H5N1 viruses in ferrets
Pearce MB , Pappas C , Gustin KM , Davis CT , Pantin-Jackwood MJ , Swayne DE , Maines TR , Belser JA , Tumpey TM . Virology 2016 502 114-122 Sporadic avian to human transmission of highly pathogenic avian influenza (HPAI) A(H5N1) viruses necessitates the analysis of currently circulating and evolving clades to assess their potential risk. Following the spread and sustained circulation of clade 2 viruses across multiple continents, numerous subclades and genotypes have been described. To better understand the pathogenesis associated with the continued diversification of clade 2A(H5N1) influenza viruses, we investigated the relative virulence of eleven human and poultry isolates collected from 2006 to 2013 by determining their ability to cause disease in the ferret model. Numerous clade 2 viruses, including a clade 2.2 avian isolate, a 2.2.2.1 human isolate, and two 2.2.1 human isolates, were found to be of low virulence in the ferret model, though lethality was detected following infection with one 2.2.1 human isolate. In contrast, three of six clade 2.3.2.1 avian isolates tested led to severe disease and death among infected ferrets. Clade 2.3.2.1b and 2.3.2.1c isolates, but not 2.3.2.1a isolates, were associated with ferret lethality. All A(H5N1) viruses replicated efficiently in the respiratory tract of ferrets regardless of their virulence and lethality. However, lethal isolates were characterized by systemic viral dissemination, including detection in the brain and enhanced histopathology in lung tissues. The finding of disparate virulence phenotypes between clade 2A(H5N1) viruses, notably differences between subclades of 2.3.2.1 viruses, suggests there are distinct molecular determinants present within the established subclades, the identification of which will assist in molecular-based surveillance and public health efforts against A(H5N1) viruses. |
Phase 1 study of pandemic h1 DNA vaccine in healthy adults
Crank MC , Gordon IJ , Yamshchikov GV , Sitar S , Hu Z , Enama ME , Holman LA , Bailer RT , Pearce MB , Koup RA , Mascola JR , Nabel GJ , Tumpey TM , Schwartz RM , Graham BS , Ledgerwood JE . PLoS One 2015 10 (4) e0123969 BACKGROUND: A novel, swine-origin influenza A (H1N1) virus was detected worldwide in April 2009, and the World Health Organization (WHO) declared a global pandemic that June. DNA vaccine priming improves responses to inactivated influenza vaccines. We describe the rapid production and clinical evaluation of a DNA vaccine encoding the hemagglutinin protein of the 2009 pandemic A/California/04/2009(H1N1) influenza virus, accomplished nearly two months faster than production of A/California/07/2009(H1N1) licensed monovalent inactivated vaccine (MIV). METHODS: 20 subjects received three H1 DNA vaccinations (4 mg intramuscularly with Biojector) at 4-week intervals. Eighteen subjects received an optional boost when the licensed H1N1 MIV became available. The interval between the third H1 DNA injection and MIV boost was 3-17 weeks. Vaccine safety was assessed by clinical observation, laboratory parameters, and 7-day solicited reactogenicity. Antibody responses were assessed by ELISA, HAI and neutralization assays, and T cell responses by ELISpot and flow cytometry. RESULTS: Vaccinations were safe and well-tolerated. As evaluated by HAI, 6/20 developed positive responses at 4 weeks after third DNA injection and 13/18 at 4 weeks after MIV boost. Similar results were detected in neutralization assays. T cell responses were detected after DNA and MIV. The antibody responses were significantly amplified by the MIV boost, however, the boost did not increased T cell responses induced by DNA vaccine. CONCLUSIONS: H1 DNA vaccine was produced quickly, was well-tolerated, and had modest immunogenicity as a single agent. Other HA DNA prime-MIV boost regimens utilizing one DNA prime vaccination and longer boost intervals have shown significant immunogenicity. Rapid and large-scale production of HA DNA vaccines has the potential to contribute to an efficient response against future influenza pandemics. TRIAL REGISTRATION: Clinicaltrials.gov NCT00973895. |
Recombinant virus-like particles elicit protective immunity against avian influenza A(H7N9) virus infection in ferrets
Liu YV , Massare MJ , Pearce MB , Sun X , Belser JA , Maines TR , Creager HM , Glenn GM , Pushko P , Smith GE , Tumpey TM . Vaccine 2015 33 (18) 2152-8 In March 2013, diagnosis of the first reported case of human infection with a novel avian-origin influenza A(H7N9) virus occurred in eastern China. Most human cases have resulted in severe respiratory illness and, in some instances, death. Currently there are no licensed vaccines against H7N9 virus, which continues to cause sporadic human infections. Recombinant virus-like particles (VLPs) have been previously shown to be safe and effective vaccines for influenza. In this study, we evaluated the immunogenicity and protective efficacy of a H7N9 VLP vaccine in the ferret challenge model. Purified recombinant H7N9 VLPs morphologically resembled influenza virions and elicited high-titer serum hemagglutination inhibition (HI) and neutralizing antibodies specific for A/Anhui/1/2013 (H7N9) virus. H7N9 VLP-immunized ferrets subsequently challenged with homologous virus displayed reductions in fever, weight loss, and virus shedding compared to these parameters in unimmunized control ferrets. H7N9 VLP was also effective in protecting against lung and tracheal infection. The addition of either ISCOMATRIX or Matrix-M1 adjuvant improved immunogenicity and protection of the VLP vaccine against H7N9 virus. These results provide support for the development of a safe and effective human VLP vaccine with potent adjuvants against avian influenza H7N9 virus with pandemic potential. |
Assessment of transmission, pathogenesis and adaptation of H2 subtype influenza viruses in ferrets
Pappas C , Yang H , Carney PJ , Pearce MB , Katz JM , Stevens J , Tumpey TM . Virology 2015 477c 61-71 After their disappearance from the human population in 1968, influenza H2 viruses have continued to circulate in the natural avian reservoir. The isolation of this virus subtype from multiple bird species as well as swine highlights the need to better understand the potential of these viruses to spread and cause disease in humans. Here we analyzed the virulence, transmissibility and receptor-binding preference of two avian influenza H2 viruses (H2N2 and H2N3) and compared them to a swine H2N3 (A/swine/Missouri/2124514/2006 [swMO]), and a human H2N2 (A/England/10/1967 [Eng/67]) virus using the ferret model as a mammalian host. Both avian H2 viruses possessed the capacity to spread efficiently between cohoused ferrets, and the swine (swMO) and human (Eng/67) viruses transmitted to naive ferrets by respiratory droplets. Further characterization of the swMO hemagglutinin (HA) by x-ray crystallography and glycan microarray array identified receptor-specific adaptive mutations. As influenza virus quasispecies dynamics during transmission have not been well characterized, we sequenced nasal washes collected during transmission studies to better understand experimental adaptation of H2 HA. The avian H2 viruses isolated from ferret nasal washes contained mutations in the HA1, including a Gln226Leu substitution, which is a mutation associated with alpha2,6 sialic acid (human-like) binding preference. These results suggest that the molecular structure of HA in viruses of the H2 subtype continue to have the potential to adapt to a mammalian host and become transmissible, after acquiring additional genetic markers. |
Impact of prior seasonal H3N2 influenza vaccination or infection on protection and transmission of emerging variants of influenza A(H3N2)v virus in ferrets
Houser KV , Pearce MB , Katz JM , Tumpey TM . J Virol 2013 87 (24) 13480-9 Influenza H3N2 A viruses continue to circulate in swine and occasionally infect humans, resulting in outbreaks of variant influenza H3N2 [A(H3N2)v] virus. It has been previously demonstrated in ferrets that A(H3N2)v viruses transmit as efficiently as seasonal influenza viruses, raising concern over the pandemic potential of these viruses. However, A(H3N2)v viruses have not acquired the ability to transmit efficiently among humans, which may be due in part to existing cross-reactive immunity to A(H3N2)v viruses. Although current seasonal H3N2 and A(H3N2)v viruses are antigenically distinct from one another, historical H3N2 viruses have some antigenic similarity to A(H3N2)v viruses and previous exposure to these viruses may provide a measure of immune protection sufficient to dampen A(H3N2)v virus transmission. Here, we evaluated whether prior seasonal H3N2 influenza virus vaccination or infection affects virus replication and transmission of A(H3N2)v virus in the ferret animal model. We found that the seasonal trivalent inactivated influenza virus vaccine (TIV) or a monovalent vaccine prepared from an antigenically related 1992 seasonal influenza H3N2 (A/Beijing/32/1992) virus failed to substantially reduce A(H3N2)v (A/Indiana/08/2011) virus shedding and subsequent transmission to naive hosts. Conversely, ferrets primed by seasonal H3N2 virus infection displayed reduced A(H3N2)v virus shedding following challenge, which blunted transmission to naive ferrets. A higher level of specific IgG and IgA antibody titers detected among infected versus vaccinated ferrets was associated with the degree of protection offered by seasonal H3N2 virus infection. The data demonstrate in ferrets that the efficiency of A(H3N2)v transmission is disrupted by preexisting immunity induced by seasonal H3N2 virus infection. |
Pathogenesis and transmission of avian influenza A (H7N9) virus in ferrets and mice
Belser JA , Gustin KM , Pearce MB , Maines TR , Zeng H , Pappas C , Sun X , Carney PJ , Villanueva JM , Stevens J , Katz JM , Tumpey TM . Nature 2013 501 (7468) 556-9 On 29 March 2013, the Chinese Center for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A(H7N9) virus. The recent human infections with H7N9 virus, totalling over 130 cases with 39 fatalities to date, have been characterized by severe pulmonary disease and acute respiratory distress syndrome (ARDS). This is concerning because H7 viruses have typically been associated with ocular disease in humans, rather than severe respiratory disease. This recent outbreak underscores the need to better understand the pathogenesis and transmission of these viruses in mammals. Here we assess the ability of A/Anhui/1/2013 and A/Shanghai/1/2013 (H7N9) viruses, isolated from fatal human cases, to cause disease in mice and ferrets and to transmit to naive animals. Both H7N9 viruses replicated to higher titre in human airway epithelial cells and in the respiratory tract of ferrets compared to a seasonal H3N2 virus. Moreover, the H7N9 viruses showed greater infectivity and lethality in mice compared to genetically related H7N9 and H9N2 viruses. The H7N9 viruses were readily transmitted to naive ferrets through direct contact but, unlike the seasonal H3N2 virus, did not transmit readily by respiratory droplets. The lack of efficient respiratory droplet transmission was corroborated by low receptor-binding specificity for human-like alpha2,6-linked sialosides. Our results indicate that H7N9 viruses have the capacity for efficient replication in mammals and human airway cells and highlight the need for continued public health surveillance of this emerging virus. |
Influenza virus h5 DNA vaccination is immunogenic by intramuscular and intradermal routes in humans.
Ledgerwood JE , Hu Z , Gordon IJ , Yamshchikov G , Enama ME , Plummer S , Bailer R , Pearce MB , Tumpey TM , Koup RA , Mascola JR , Nabel GJ , Graham BS . Clin Vaccine Immunol 2012 19 (11) 1792-7 Avian influenza virus causes outbreaks in domestic and wild birds around the world, and sporadic human infections have been reported. A DNA vaccine encoding hemagglutinin (HA) protein from the A/Indonesia/5/05 (H5N1) strain was initially tested in two randomized phase I clinical studies. Vaccine Research Center study 304 (VRC 304) was a double-blinded study with 45 subjects randomized to placebo, 1 mg of vaccine, or 4 mg of vaccine treatment groups (n = 15/group) by intramuscular (i.m.) Biojector injection. VRC 305 was an open-label study to evaluate route, with 44 subjects randomized to intradermal (i.d.) injections of 0.5 mg by needle/syringe or by Biojector or 1 mg delivered as two 0.5-mg Biojector injections in the same deltoid or as 0.5 mg in each deltoid (n = 11/group). Injections were administered at weeks 0, 4, and 8 in both studies. Antibody responses to H5 were assessed by hemagglutination inhibition (HAI) assay, enzyme-linked immunosorbent assay (ELISA), and neutralization assay, and the H5 T cell responses were assessed by enzyme-linked immunospot and intracellular cytokine staining assays. There were no vaccine-related serious adverse events, and the vaccine was well tolerated in all groups. At 1 mg, i.d. vaccination compared to i.m. vaccination induced a greater frequency and magnitude of response by ELISA, but there were no significant differences in the frequency or magnitude of response between the i.d. and i.m. routes in the HAI or neutralization assays. T cell responses were more common in subjects who received the 1- or 4-mg dose i.m. These studies demonstrated that the DNA vaccine encoding H5 is safe and immunogenic and served to define the proper dose and route for further studies. The i.d. injection route did not offer a significant advantage over the i.m. route, and no difference was detected by delivery to one site versus splitting the dose between two sites for i.d. vaccine administration. The 4-mg dose (i.m) was further investigated in prime-boost regimens. |
Seasonal trivalent inactivated influenza vaccine protects against 1918 Spanish influenza virus in ferrets
Pearce MB , Belser JA , Gustin KM , Pappas C , Houser KV , Sun X , Maines TR , Pantin-Jackwood MJ , Katz JM , Tumpey TM . J Virol 2012 86 (13) 7118-25 The influenza H1N1 pandemic of 1918 was one of the worst medical catastrophes in human history. Recent studies have demonstrated that the hemagglutinin (HA) protein of the 1918 virus and 2009 H1N1 pandemic virus [A(H1N1)pdm09], the latter now a component of the seasonal trivalent inactivated influenza vaccine (TIV), share cross-reactive antigenic determinants. In this study, we demonstrate that immunization with the 2010-11 seasonal TIV induces neutralizing antibodies that cross-react with the reconstructed 1918 pandemic virus in ferrets. TIV-immunized ferrets subsequently challenged with the 1918 virus displayed a significant reduction in fever, weight loss and virus shedding compared to non-immune control ferrets. Seasonal TIV was also effective in protecting against lung infection and severe lung pathology associated with 1918 virus infection. Our data demonstrate that prior immunization with contemporary TIV provides cross-protection against the 1918 virus in ferrets. These findings suggest that exposure to A(H1N1)pdm09 through immunization, may provide protection against the reconstructed 1918 virus which as a select agent is considered to pose both biosafety and biosecurity threats. |
Pathogenesis and transmission of swine origin A(H3N2)v influenza viruses in ferrets
Pearce MB , Jayaraman A , Pappas C , Belser JA , Zeng H , Gustin KM , Maines TR , Sun X , Raman R , Cox NJ , Sasisekharan R , Katz JM , Tumpey TM . Proc Natl Acad Sci U S A 2012 109 (10) 3944-9 Recent isolation of a novel swine-origin influenza A H3N2 variant virus [A(H3N2)v] from humans in the United States has raised concern over the pandemic potential of these viruses. Here, we analyzed the virulence, transmissibility, and receptor-binding preference of four A(H3N2)v influenza viruses isolated from humans in 2009, 2010, and 2011. High titers of infectious virus were detected in nasal turbinates and nasal wash samples of A(H3N2)v-inoculated ferrets. All four A(H3N2)v viruses possessed the capacity to spread efficiently between cohoused ferrets, and the 2010 and 2011 A(H3N2)v isolates transmitted efficiently to naive ferrets by respiratory droplets. A dose-dependent glycan array analysis of A(H3N2)v showed a predominant binding to alpha2-6-sialylated glycans, similar to human-adapted influenza A viruses. We further tested the viral replication efficiency of A(H3N2)v viruses in a relevant cell line, Calu-3, derived from human bronchial epithelium. The A(H3N2)v viruses replicated in Calu-3 cells to significantly higher titers compared with five common seasonal H3N2 influenza viruses. These findings suggest that A(H3N2)v viruses have the capacity for efficient replication and transmission in mammals and underscore the need for continued public health surveillance. |
Oseltamivir inhibits H7 influenza virus replication in mice inoculated by the ocular route
Belser JA , Sleeman K , Pearce MB , Katz JM , Gubareva LV , Tumpey TM . Antimicrob Agents Chemother 2011 56 (3) 1616-8 The majority of human infections associated with H7 influenza viruses have resulted in ocular and not respiratory disease. While oseltamivir has been prescribed to individuals presenting with conjunctivitis following H7 virus exposure, it is unknown if oseltamivir inhibits virus replication in ocular tissue. We demonstrate that H7 viruses possess sensitivity to neuraminidase inhibitors, and that administration of oseltamivir before ocular virus challenge in mice inhibits H7N7 and H7N3 virus replication in ocular and respiratory tissues. |
DNA priming and influenza vaccine immunogenicity: two phase 1 open label randomised clinical trials.
Ledgerwood JE , Wei CJ , Hu Z , Gordon IJ , Enama ME , Hendel CS , McTamney PM , Pearce MB , Yassine HM , Boyington JC , Bailer R , Tumpey TM , Koup RA , Mascola JR , Nabel GJ , Graham BS . Lancet Infect Dis 2011 11 (12) 916-924 BACKGROUND: Because the general population is largely naive to H5N1 influenza, antibodies generated to H5 allow analysis of novel influenza vaccines independent of background immunity from previous infection. We assessed the safety and immunogenicity of DNA encoding H5 as a priming vaccine to improve antibody responses to inactivated influenza vaccination. METHODS: In VRC 306 and VRC 310, two sequentially enrolled phase 1, open-label, randomised clinical trials, healthy adults (age 18-60 years) were randomly assigned to receive intramuscular H5 DNA (4 mg) at day 0 or twice, at day 0 and week 4, followed by H5N1 monovalent inactivated vaccine (MIV; 90 mcg) at 4 or 24 weeks, and compared with a two-dose regimen of H5N1 MIV with either a 4 or 24 week interval. Antibody responses were assessed by haemagglutination inhibition (HAI), ELISA, neutralisation (ID(80)), and immunoassays for stem-directed antibodies. T cell responses were assessed by intracellular cytokine staining. After enrolment, investigators and individuals were not masked to group assignment. VRC 306 and VRC 310 are registered with ClinicalTrials.gov, numbers NCT00776711 and NCT01086657, respectively. FINDINGS: In VRC 306, 60 individuals were randomly assigned to the four groups (15 in each) and 59 received the vaccinations. In VRC 310, of the 21 individuals enrolled, 20 received the vaccinations (nine received a two-dose regimen of H5N1 MIV and 11 received H5 DNA at day 0 followed by H5N1 MIV at week 24). H5 DNA priming was safe and enhanced H5-specific antibody titres following an H5N1 MIV boost, especially when the interval between DNA prime and MIV boost was extended to 24 weeks. In the two studies, DNA priming with a 24-week MIV boost interval induced protective HAI titres in 21 (81%) of 26 of individuals, with an increase in geometric mean titre (GMT) of more than four times that of individuals given the MIV-MIV regimen at 4 or 24 weeks (GMT 103-206 vs GMT 27-33). Additionally, neutralising antibodies directed to the conserved stem region of H5 were induced by this prime-boost regimen in several individuals. No vaccine-related serious adverse events were recorded. INTERPRETATION: DNA priming 24 weeks in advance of influenza vaccine boosting increased the magnitude of protective antibody responses (HAI) and in some cases induced haemagglutinin-stem-specific neutralising antibodies. A DNA-MIV vaccine regimen could enhance the efficacy of H5 or other influenza vaccines and shows that anti-stem antibodies can be elicited by vaccination in man. FUNDING: National Institutes of Health. |
Influenza virus-like particle can accommodate multiple subtypes of hemagglutinin and protect from multiple influenza types and subtypes
Pushko P , Pearce MB , Ahmad A , Tretyakova I , Smith G , Belser JA , Tumpey TM . Vaccine 2011 29 (35) 5911-8 Despite existing vaccines and specific therapies, epidemics of seasonal influenza annually claim 200,000-500,000 lives worldwide. Pandemic influenza represents an even greater threat, with numerous potentially pandemic viruses circulating in nature. Development of multi-specific vaccines against multiple pandemic or seasonal strains is important for human health and the global economy. Here we report a novel virus-like particle (VLP) platform that contains three hemagglutinin (HA) subtypes. This recombinant vaccine design resulted in the expression of three HA subtypes co-localized within a VLP. Experimental triple-HA VLPs containing HA proteins derived from H5N1, H7N2, and H2N3 viruses were immunogenic and protected ferrets from challenge from all three potentially pandemic viruses. Similarly, VLPs containing HA subtypes derived from seasonal H1N1, H3N2, and type B influenza viruses protected ferrets from three seasonal influenza viruses. We conclude that this technology may represent a novel strategy for rapid development of trivalent seasonal and pandemic vaccines. |
Influenza virus aerosol exposure and analytical system for ferrets
Gustin KM , Belser JA , Wadford DA , Pearce MB , Katz JM , Tumpey TM , Maines TR . Proc Natl Acad Sci U S A 2011 108 (20) 8432-7 Understanding the transmission ability of newly emerging influenza viruses is central to the development of public health preparedness and prevention strategies. Animals are used to model influenza virus infection and transmission, but the routinely used intranasal inoculation of a liquid virus suspension does not reflect natural infection. We report the development of an inoculation method that delivers an influenza virus aerosol inoculum to ferrets and the characterization of size distribution and viable virus present in aerosols shed from infected ferrets during normal breathing and sneezing. By comparing virus deposition, infectivity, virulence, and transmissibility among animals inoculated intranasally or by aerosols with a human (H3N2) or avian (H5N1) influenza virus, we demonstrate that aerosol inoculations more closely resemble a natural, airborne influenza virus infection and that viable virus is measurable in droplets and droplet nuclei exhaled by infected ferrets. These methods will provide improved risk assessment of emerging influenza viruses that pose a threat to public health. |
Effect of receptor binding domain mutations on receptor binding and transmissibility of avian influenza H5N1 viruses
Maines TR , Chen LM , Van Hoeven N , Tumpey TM , Blixt O , Belser JA , Gustin KM , Pearce MB , Pappas C , Stevens J , Cox NJ , Paulson JC , Raman R , Sasisekharan R , Katz JM , Donis RO . Virology 2011 413 (1) 139-47 Although H5N1 influenza viruses have been responsible for hundreds of human infections, these avian influenza viruses have not fully adapted to the human host. The lack of sustained transmission in humans may be due, in part, to their avian-like receptor preference. Here, we have introduced receptor binding domain mutations within the hemagglutinin (HA) gene of two H5N1 viruses and evaluated changes in receptor binding specificity by glycan microarray analysis. The impact of these mutations on replication efficiency was assessed in vitro and in vivo. Although certain mutations switched the receptor binding preference of the H5 HA, the rescued mutant viruses displayed reduced replication in vitro and delayed peak virus shedding in ferrets. An improvement in transmission efficiency was not observed with any of the mutants compared to the parental viruses, indicating that alternative molecular changes are required for H5N1 viruses to fully adapt to humans and to acquire pandemic capability. |
Efficacy of seasonal live attenuated influenza vaccine against virus replication and transmission of a pandemic 2009 H1N1 virus in ferrets
Pearce MB , Belser JA , Houser KV , Katz JM , Tumpey TM . Vaccine 2011 29 (16) 2887-94 In March 2009, a swine origin influenza A (2009 H1N1) virus was introduced into the human population and quickly spread from North America to multiple continents. Human serologic studies suggest that seasonal influenza virus vaccination or infection would provide little cross-reactive serologic immunity to the pandemic 2009 H1N1 virus. However, the efficacy of seasonal influenza infection or vaccination against 2009 H1N1 virus replication and transmission has not been adequately evaluated in vivo. Here, ferrets received one or two doses of the US licensed 2008-2009 live attenuated influenza vaccine (LAIV) intranasally. An additional group of ferrets were inoculated with the A/Brisbane/59/07 (H1N1) virus to model immunity induced by seasonal influenza virus infection. All vaccinated and infected animals possessed high titer homologous hemagglutination-inhibition (HI) and neutralizing antibodies, with no demonstrable cross-reactive antibodies against 2009 H1N1 virus. However, in comparison to non-immune controls, immunized ferrets challenged with pandemic A/Mexico/4482/09 virus displayed a significant reduction in body temperature and virus shedding. The impact of single-dose LAIV inoculation on 2009 H1N1 disease and virus transmission was also measured in vaccinated ferrets that were challenged with pandemic A/Netherlands/1132/09 virus. Although a single dose of LAIV reduced virus shedding and the frequency of transmission following homologous seasonal virus challenge, it failed to reduce respiratory droplet transmission of 2009 H1N1 virus. The results demonstrate that prior immunization with seasonal LAIV or H1N1 virus infection provides some cross-protection against the 2009 H1N1 virus, but had no significant effect on the transmission efficiency of the 2009 H1N1 virus. |
NS-based live attenuated H1N1 pandemic vaccines protect mice and ferrets
Zhou B , Li Y , Belser JA , Pearce MB , Schmolke M , Subba AX , Shi Z , Zaki SR , Blau DM , Garcia-Sastre A , Tumpey TM , Wentworth DE . Vaccine 2010 28 (50) 8015-25 Although vaccines against influenza A virus are the most effective method to combat infection, it is clear that their production needs to be accelerated and their efficacy improved. We generated live attenuated human influenza A vaccines (LAIVs) by rationally engineering mutations directly into the genome of a pandemic-H1N1 virus. Two LAIVs (NS1-73 and NS1-126) were based on the success of LAIVs for animal influenza A viruses. A third candidate (NSDelta5) is a unique NS-mutant that has never been used as a LAIV. The vaccine potential of each LAIV was determined through analysis of attenuation, interferon production, immunogenicity, and their ability to protect mice and ferrets. This study demonstrates that NSDelta5 is an ideal LAIV candidate, provides important information on the effects that different NS mutations have on the pandemic-H1N1 virus and shows that LAIVs can be engineered directly from the genomes of emerging/circulating influenza A viruses. |
Single-dose mucosal immunization with a candidate universal influenza vaccine provides rapid protection from virulent H5N1, H3N2 and H1N1 viruses
Price GE , Soboleski MR , Lo CY , Misplon JA , Quirion MR , Houser KV , Pearce MB , Pappas C , Tumpey TM , Epstein SL . PLoS One 2010 5 (10) e13162 BACKGROUND: The sudden emergence of novel influenza viruses is a global public health concern. Conventional influenza vaccines targeting the highly variable surface glycoproteins hemagglutinin and neuraminidase must antigenically match the emerging strain to be effective. In contrast, "universal" vaccines targeting conserved viral components could be used regardless of viral strain or subtype. Previous approaches to universal vaccination have required protracted multi-dose immunizations. Here we evaluate a single dose universal vaccine strategy using recombinant adenoviruses (rAd) expressing the conserved influenza virus antigens matrix 2 and nucleoprotein. METHODOLOGY/PRINCIPAL FINDINGS: In BALB/c mice, administration of rAd via the intranasal route was superior to intramuscular immunization for induction of mucosal responses and for protection against highly virulent H1N1, H3N2, or H5N1 influenza virus challenge. Mucosally vaccinated mice not only survived, but had little morbidity and reduced lung virus titers. Protection was observed as early as 2 weeks post-immunization, and lasted at least 10 months, as did antibodies and lung T cells with activated phenotypes. Virus-specific IgA correlated with but was not essential for protection, as demonstrated in studies with IgA-deficient animals. CONCLUSION/SIGNIFICANCE: Mucosal administration of NP and M2-expressing rAd vectors provided rapid and lasting protection from influenza viruses in a subtype-independent manner. Such vaccines could be used in the interval between emergence of a new virus strain and availability of strain-matched vaccines against it. This strikingly effective single-dose vaccination thus represents a candidate off-the-shelf vaccine for emergency use during an influenza pandemic. |
Induction of broadly neutralizing H1N1 influenza antibodies by vaccination
Wei CJ , Boyington JC , McTamney PM , Kong WP , Pearce MB , Xu L , Andersen H , Rao S , Tumpey TM , Yang ZY , Nabel GJ . Science 2010 329 (5995) 1060-4 The rapid dissemination of the 2009 pandemic influenza virus underscores the need for universal influenza vaccines that elicit protective immunity to diverse viral strains. Here, we show that vaccination with plasmid DNA encoding H1N1 influenza hemagglutinin (HA) and boosting with seasonal vaccine or replication-defective adenovirus 5 vector encoding HA stimulated the production of broadly neutralizing influenza antibodies. This prime/boost combination increased the neutralization of diverse H1N1 strains dating from 1934 to 2007 as compared to either component alone and conferred protection against divergent H1N1 viruses in mice and ferrets. These antibodies were directed to the conserved stem region of HA and were also elicited in nonhuman primates. Cross-neutralization of H1N1 subtypes elicited by this approach provides a basis for the development of a universal influenza vaccine for humans. |
Recombinant H1N1 virus-like particle vaccine elicits protective immunity in ferrets against the 2009 pandemic H1N1 influenza virus
Pushko P , Kort T , Nathan M , Pearce MB , Smith G , Tumpey TM . Vaccine 2010 28 (30) 4771-6 The pandemic virus of 2009 (2009 H1N1) continues to cause illness worldwide, especially in younger age groups. The widespread H1N1 virus infection further emphasizes the need for vaccine strategies that are effective against emerging pandemic viruses and are not dependent on the limitations of traditional egg-based technology. This report describes a recombinant influenza virus-like particle (VLP) vaccine consisting of hemagglutinin (HA), neuraminidase (NA), and matrix (M1) proteins of influenza A/California/04/2009 (H1N1) virus. Influenza H1N1 VLPs with a diameter of approximately 120nm were released into the culture medium from Sf9 insect cells infected with recombinant baculovirus coexpressing HA, NA, and M1 proteins. Purified recombinant H1N1 VLPs morphologically resembled influenza virions and exhibited biological characteristics of influenza virus, including HA and NA activities. In the ferret challenge model, 2009 influenza H1N1 VLPs elicited high-titer serum hemagglutination inhibition (HI) antibodies specific for the 2009 H1N1 virus and inhibited replication of the influenza virus in the upper and lower respiratory tract tissues following A/Mexico/4482/09 (H1N1) virus challenge. Moreover, a single 15mug dose of H1N1 VLPs resulted in complete virus clearance in the ferret lung. These results provide support for the use of recombinant influenza VLP vaccine as an effective strategy against pandemic H1N1 virus. |
5'PPP-RNA induced RIG-I activation inhibits drug-resistant avian H5N1 as well as 1918 and 2009 pandemic influenza virus replication
Ranjan P , Jayashankar L , Deyde V , Zeng H , Davis WG , Pearce MB , Bowzard JB , Hoelscher MA , Jeisy-Scott V , Wiens ME , Gangappa S , Gubareva L , Garcia-Sastre A , Katz JM , Tumpey TM , Fujita T , Sambhara S . Virol J 2010 7 (1) 102 BACKGROUND: Emergence of drug-resistant strains of influenza viruses, including avian H5N1 with pandemic potential, 1918 and 2009 A/H1N1 pandemic viruses to currently used antiviral agents, neuraminidase inhibitors and M2 Ion channel blockers, underscores the importance of developing novel antiviral strategies. Activation of innate immune pathogen sensor Retinoic Acid Inducible Gene-I (RIG-I) has recently been shown to induce antiviral state. RESULTS: In the present investigation, using real time RT-PCR, immunofluorescence, immunoblot, and plaque assay we show that 5'PPP-containing single stranded RNA (5PPP-RNA), a ligand for the intracytoplasmic RNA sensor, RIG-I can be used as a prophylactic agent against known drug-resistant avian H5N1 and pandemic influenza viruses. 5'PPP-RNA treatment of human lung epithelial cells inhibited replication of drug-resistant avian H5N1 as well as 1918 and 2009 pandemic influenza viruses in a RIG-I and type 1 interferon dependant manner. Additionally, 5'PPP-RNA treatment also inhibited 2009 H1N1 viral replication in vivo in mice. CONCLUSIONS: Our findings suggest that 5PPP-RNA mediated activation of RIG-I can suppress replication of influenza viruses irrespective of their genetic make-up, pathogenicity, and drug-sensitivity status. |
Pathogenesis of pandemic influenza A (H1N1) and triple-reassortant swine influenza A (H1) viruses in mice
Belser JA , Wadford DA , Pappas C , Gustin KM , Maines TR , Pearce MB , Zeng H , Swayne DE , Pantin-Jackwood M , Katz JM , Tumpey TM . J Virol 2010 84 (9) 4194-203 The pandemic H1N1 virus of 2009 (2009 H1N1) continues to cause illness worldwide, primarily in younger age groups. To better understand the pathogenesis of these viruses in mammals, we used a mouse model to evaluate the relative virulence of selected 2009 H1N1 viruses and compared them to a representative human triple-reassortant swine influenza virus that has circulated in pigs in the United States for over a decade preceding the current pandemic. Additional comparisons were made with the reconstructed 1918 virus, a 1976 H1N1 swine influenza virus, and a highly pathogenic H5N1 virus. Mice were inoculated intranasally with each virus and monitored for morbidity, mortality, viral replication, hemostatic parameters, cytokine production and lung histology. All 2009 H1N1 viruses replicated efficiently in the lungs of mice and possessed a high degree of infectivity, but did not cause lethal disease or exhibit extrapulmonary virus spread. Transient weight loss, lymphopenia, and proinflammatory cytokine and chemokine production were present following 2009 H1N1 virus infection, but these levels were generally muted compared with a triple-reassortant swine virus and the 1918 virus. 2009 H1N1 viruses isolated from fatal cases did not demonstrate enhanced virulence in this model compared with isolates from mild human cases. Histologically, infection with the 2009 viruses resulted in lesions in the lung varying from mild to moderate bronchiolitis with occasional necrosis of bronchiolar epithelium, and mild to moderate peribronchiolar alveolitis. Taken together, these studies demonstrate that the 2009 H1N1 viruses exhibited mild to moderate virulence in mice compared with highly pathogenic viruses. |
PB1-F2 expression by the 2009 pandemic H1N1 influenza virus has minimal impact on virulence in animal models
Hai R , Schmolke M , Varga ZT , Manicassamy B , Wang TT , Belser JA , Pearce MB , Garcia-Sastre A , Tumpey TM , Palese P . J Virol 2010 84 (9) 4442-50 Unlike previous pandemic viruses, the 2009 H1N1 pandemic influenza virus does not code for the virulence factor PB1-F2. The genome of the 2009 H1N1 virus contains three stop codons preventing PB1-F2 expression; however, PB1-F2 production could occur following genetic mutation or reassortment. Thus, it is of great interest to understand the impact that expression of the PB1-F2 protein might have in the context of the 2009 pandemic influenza virus, A/California/04/2009 (Cal/09). We have addressed this question by generating two Cal/09 viruses with productive PB1-F2 open reading frames containing either an asparagine at position 66 of PB1-F2 (66N) or a serine at position 66 (66S): this N66S change has previously been shown to be associated with increased virulence in mice. We used these viruses to investigate the effect on virulence conferred by expression of the 66N or 66S PB1-F2 proteins in both in vitro and in vivo systems. Our results show enhanced replication of the 66S virus in A549 cells, while studies in BALB/c and DBA/2 mice and in ferrets revealed no significant differences in symptoms of infection with the wild-type Cal/09, the 66N or the 66S virus variants. Also co-infection of mice with Streptococcus pneumoniae and the different viruses (rWT Cal/09, 66N and 66S) did not result in significant differences in mortality. Mice infected with either PB1-F2-expressing virus did demonstrate altered protein levels of pro-inflammatory cytokines; differences were observed to be greater in infection caused by the 66S virus. In summary, our study demonstrates that PB1-F2 expression by the Cal/09 virus modulates the immune response to infection while having minimal effect on virus virulence in two mammalian models. |
Naturally occurring human monoclonal antibodies neutralize both 1918 and 2009 A(H1N1) pandemic influenza viruses
Krause JC , Tumpey TM , Huffman CJ , McGraw PA , Pearce MB , Tsibane T , Hai R , Basler CF , Crowe JE Jr . J Virol 2009 84 (6) 3127-30 The 2009 A(H1N1) pandemic influenza virus exhibits hemagglutinin protein sequence homology with the 1918 pandemic influenza virus. We found that human monoclonal antibodies recognized the Sa antigenic site on the head domain of both 1918 and 2009 hemagglutinins, a site that is hypervariable due to immune selection. These antibodies exhibited high potency against the 2009 virus in vitro, and one exerted a marked therapeutic effect in vivo. |
Novel pandemic influenza A(H1N1) viruses are potently inhibited by DAS181, a sialidase fusion protein
Triana-Baltzer GB , Gubareva LV , Nicholls JM , Pearce MB , Mishin VP , Belser JA , Chen LM , Chan RW , Chan MC , Hedlund M , Larson JL , Moss RB , Katz JM , Tumpey TM , Fang F . PLoS One 2009 4 (11) e7788 BACKGROUND: The recent emergence of a novel pandemic influenza A(H1N1) strain in humans exemplifies the rapid and unpredictable nature of influenza virus evolution and the need for effective therapeutics and vaccines to control such outbreaks. However, resistance to antivirals can be a formidable problem as evidenced by the currently widespread oseltamivir- and adamantane-resistant seasonal influenza A viruses (IFV). Additional antiviral approaches with novel mechanisms of action are needed to combat novel and resistant influenza strains. DAS181 (Fludase) is a sialidase fusion protein in early clinical development with in vitro and in vivo preclinical activity against a variety of seasonal influenza strains and highly pathogenic avian influenza strains (A/H5N1). Here, we use in vitro, ex vivo, and in vivo models to evaluate the activity of DAS181 against several pandemic influenza A(H1N1) viruses. METHODS AND FINDINGS: The activity of DAS181 against several pandemic influenza A(H1N1) virus isolates was examined in MDCK cells, differentiated primary human respiratory tract culture, ex-vivo human bronchi tissue and mice. DAS181 efficiently inhibited viral replication in each of these models and against all tested pandemic influenza A(H1N1) strains. DAS181 treatment also protected mice from pandemic influenza A(H1N1)-induced pathogenesis. Furthermore, DAS181 antiviral activity against pandemic influenza A(H1N1) strains was comparable to that observed against seasonal influenza virus including the H274Y oseltamivir-resistant influenza virus. CONCLUSIONS: The sialidase fusion protein DAS181 exhibits potent inhibitory activity against pandemic influenza A(H1N1) viruses. As inhibition was also observed with oseltamivir-resistant IFV (H274Y), DAS181 may be active against the antigenically novel pandemic influenza A(H1N1) virus should it acquire the H274Y mutation. Based on these and previous results demonstrating DAS181 broad-spectrum anti-IFV activity, DAS181 represents a potential therapeutic agent for prevention and treatment of infections by both emerging and seasonal strains of IFV. |
RIG-I activation inhibits ebolavirus replication
Spiropoulou CF , Ranjan P , Pearce MB , Sealy TK , Albarino CG , Gangappa S , Fujita T , Rollin PE , Nichol ST , Ksiazek TG , Sambhara S . Virology 2009 392 (1) 11-5 Hemorrhagic fever viruses are associated with rapidly progressing severe disease with high case fatality, making them of public health and biothreat importance. Effective antivirals are not available for most of the members of this diverse group of viruses. A broad spectrum strategy for antiviral development would be very advantageous. Perhaps the most challenging target would be the highly immunosuppressive filoviruses, ebolavirus and marburgvirus, associated with aerosol infectivity and case fatalities in the 80-90% range. Here we report that activation of evolutionarily conserved cytosolic viral nucleic acid sensor, RIG-I can cause severe inhibition of ebolavirus replication. These findings indicate that RIG-I-based therapies may provide an attractive approach for antivirals against Ebola hemorrhagic fever, and possibly other HF viruses. |
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