In Vivo Localization of Staphylococcus aureus in Nasal Tissues of Healthy and Influenza A Virus-Infected Ferrets

ABSTRACT Influenza A virus (IAV) causes annual epidemics of respiratory disease in humans, often complicated by secondary coinfection with bacterial pathogens such as Staphylococcus aureus. Here, we report that the S. aureus secreted protein lipase 1 enhances IAV replication in vitro in primary cells, including human lung fibroblasts. The proviral activity of lipase 1 is dependent on its enzymatic function, acts late in the viral life cycle, and results in increased infectivity through positive modulation of virus budding. Furthermore, the proviral effect of lipase 1 on IAV is exhibited during in vivo infection of embryonated hen’s eggs and, importantly, increases the yield of a vaccine strain of IAV by approximately 5-fold. Thus, we have identified the first S. aureus protein to enhance IAV replication, suggesting a potential role in coinfection. Importantly, this activity may be harnessed to address global shortages of influenza vaccines. IMPORTANCE Influenza A virus (IAV) causes annual epidemics and sporadic pandemics of respiratory disease. Secondary bacterial coinfection by organisms such as Staphylococcus aureus is the most common complication of primary IAV infection and is associated with high levels of morbidity and mortality. Here, we report the first identified S. aureus factor (lipase 1) that enhances IAV replication during infection via positive modulation of virus budding. The effect is observed in vivo in embryonated hen’s eggs and greatly enhances the yield of a vaccine strain, a finding that could be applied to address global shortages of influenza vaccines.

Download Full-text

Streptococcus pneumoniae Modulates Staphylococcus aureus Biofilm Dispersion and the Transition from Colonization to Invasive Disease

mBio ◽

10.1128/mbio.02089-17 ◽

2018 ◽

Vol 9 (1) ◽

Cited By ~ 12

Author(s):

Ryan M. Reddinger ◽

Nicole R. Luke-Marshall ◽

Shauna L. Sauberan ◽

Anders P. Hakansson ◽

Anthony A. Campagnari

Keyword(s):

Staphylococcus Aureus ◽

Streptococcus Pneumoniae ◽

Influenza A Virus ◽

Bacterial Pneumonia ◽

Influenza A ◽

Bacterial Species ◽

Invasive Disease ◽

Secondary Bacterial Pneumonia

ABSTRACTStreptococcus pneumoniaeandStaphylococcus aureusare ubiquitous upper respiratory opportunistic pathogens. Individually, these Gram-positive microbes are two of the most common causative agents of secondary bacterial pneumonia following influenza A virus infection, and they constitute a significant source of morbidity and mortality. Since the introduction of the pneumococcal conjugate vaccine, rates of cocolonization with both of these bacterial species have increased, despite the traditional view that they are antagonistic and mutually exclusive. The interactions betweenS. pneumoniaeandS. aureusin the context of colonization and the transition to invasive disease have not been characterized. In this report, we show thatS. pneumoniaeandS. aureusform stable dual-species biofilms on epithelial cellsin vitro. When these biofilms are exposed to physiological changes associated with viral infection,S. pneumoniaedisperses from the biofilm, whereasS. aureusdispersal is inhibited. These findings were supported by results of anin vivostudy in which we used a novel mouse cocolonization model. In these experiments, mice cocolonized in the nares with both bacterial species were subsequently infected with influenza A virus. The coinfected mice almost exclusively developed pneumococcal pneumonia. These results indicate that despite our previous report thatS. aureusdisseminates into the lungs of mice stably colonized with these bacteria following influenza A virus infection, cocolonization withS. pneumoniae in vitroandin vivoinhibitsS. aureusdispersal and transition to disease. This study provides novel insight into both the interactions betweenS. pneumoniaeandS. aureusduring carriage and the transition from colonization to secondary bacterial pneumonia.IMPORTANCEIn this study, we demonstrate thatStreptococcus pneumoniaecan modulate the pathogenic potential ofStaphylococcus aureusin a model of secondary bacterial pneumonia. We report that host physiological signals related to viral infection cease to elicit a dispersal response fromS. aureuswhile in a dual-species setting withS. pneumoniae, in direct contrast to results of previous studies with each species individually. This study underscores the importance of studying polymicrobial communities and their implications in disease states.

Download Full-text

Impact of Influenza A Virus Shutoff Proteins on Host Immune Responses

Vaccines ◽

10.3390/vaccines9060629 ◽

2021 ◽

Vol 9 (6) ◽

pp. 629

Author(s):

Megan M. Dunagan ◽

Kala Hardy ◽

Toru Takimoto

Keyword(s):

Immune Response ◽

Immune Responses ◽

Influenza A Virus ◽

Influenza A ◽

Human Populations ◽

Lymphocyte Migration ◽

Host Immune Responses ◽

Mhc Molecules ◽

The Impact

Influenza A virus (IAV) is a significant human pathogen that causes seasonal epidemics. Although various types of vaccines are available, IAVs still circulate among human populations, possibly due to their ability to circumvent host immune responses. IAV expresses two host shutoff proteins, PA-X and NS1, which antagonize the host innate immune response. By transcriptomic analysis, we previously showed that PA-X is a major contributor for general shutoff, while shutoff active NS1 specifically inhibits the expression of host cytokines, MHC molecules, and genes involved in innate immunity in cultured human cells. So far, the impact of these shutoff proteins in the acquired immune response in vivo has not been determined in detail. In this study, we analyzed the effects of PA-X and NS1 shutoff activities on immune response using recombinant influenza A/California/04/2009 viruses containing mutations affecting the expression of shutoff active PA-X and NS1 in a mouse model. Our data indicate that the virus without shutoff activities induced the strongest T and B cell responses. Both PA-X and NS1 reduced host immune responses, but shutoff active NS1 most effectively suppressed lymphocyte migration to the lungs, antibody production, and the generation of IAV specific CD4+ and CD8+ T cells. NS1 also prevented the generation of protective immunity against a heterologous virus challenge. These data indicate that shutoff active NS1 plays a major role in suppressing host immune responses against IAV infection.

Download Full-text

Viral dosing of influenza A infection reveals involvement of RIPK3 and FADD, but not MLKL

Cell Death and Disease ◽

10.1038/s41419-021-03746-0 ◽

2021 ◽

Vol 12 (5) ◽

Author(s):

Teodora Oltean ◽

Emily Van San ◽

Tatyana Divert ◽

Tom Vanden Berghe ◽

Xavier Saelens ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Kinase Activity ◽

Dose Range ◽

Challenge Dose

AbstractRIPK3 was reported to play an important role in the protection against influenza A virus (IAV) in vivo. Here we show that the requirement of RIPK3 for protection against IAV infection in vivo is only apparent within a limited dose range of IAV challenge. We found that this protective outcome is independent from RIPK3 kinase activity and from MLKL. This shows that platform function of RIPK3 rather than its kinase activity is required for protection, suggesting that a RIPK3 function independent of necroptosis is implicated. In line with this finding, we show that FADD-dependent apoptosis has a crucial additional effect in protection against IAV infection. Altogether, we show that RIPK3 contributes to protection against IAV in a narrow challenge dose range by a mechanism that is independent of its kinase activity and its capacity to induce necroptosis.

Download Full-text

Antiviral activity of Ladania067, an extract from wild black currant leaves against influenza A virus in vitro and in vivo

Frontiers in Microbiology ◽

10.3389/fmicb.2014.00171 ◽

2014 ◽

Vol 5 ◽

Cited By ~ 12

Author(s):

Emanuel Haasbach ◽

Carmen Hartmayer ◽

Alice Hettler ◽

Alicja Sarnecka ◽

Ulrich Wulle ◽

...

Keyword(s):

Antiviral Activity ◽

Influenza A Virus ◽

Influenza A ◽

Black Currant

Download Full-text

Exacerbation of Influenza A Virus Disease Severity by Respiratory Syncytial Virus Co-Infection in a Mouse Model

Viruses ◽

10.3390/v13081630 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1630 ◽

Cited By ~ 1

Author(s):

Junu A. George ◽

Shaikha H. AlShamsi ◽

Maryam H. Alhammadi ◽

Ahmed R. Alsuwaidi

Keyword(s):

T Cells ◽

Respiratory Syncytial Virus ◽

Influenza A Virus ◽

Influenza A ◽

Immune Cell ◽

Virus Disease ◽

Viral Loads ◽

Syncytial Virus

Influenza A virus (IAV) and respiratory syncytial virus (RSV) are leading causes of childhood infections. RSV and influenza are competitive in vitro. In this study, the in vivo effects of RSV and IAV co-infection were investigated. Mice were intranasally inoculated with RSV, with IAV, or with both viruses (RSV+IAV and IAV+RSV) administered sequentially, 24 h apart. On days 3 and 7 post-infection, lung tissues were processed for viral loads and immune cell populations. Lung functions were also evaluated. Mortality was observed only in the IAV+RSV group (50% of mice did not survive beyond 7 days). On day 3, the viral loads in single-infected and co-infected mice were not significantly different. However, on day 7, the IAV titer was much higher in the IAV+RSV group, and the RSV viral load was reduced. CD4 T cells were reduced in all groups on day 7 except in single-infected mice. CD8 T cells were higher in all experimental groups except the RSV-alone group. Increased airway resistance and reduced thoracic compliance were demonstrated in both co-infected groups. This model indicates that, among all the infection types we studied, infection with IAV followed by RSV is associated with the highest IAV viral loads and the most morbidity and mortality.

Download Full-text

The combination of ribavirin and ozeltamivir effectively inhibits reproduction of influenza a virus resistant to rimantadine (Amantadine) in vitro and in vivo

Doklady Biochemistry and Biophysics ◽

10.1134/s1607672914020100 ◽

2014 ◽

Vol 455 (1) ◽

pp. 80-83 ◽

Cited By ~ 3

Author(s):

P. G. Deryabin ◽

G. A. Galegov ◽

I. D. Konstantinova ◽

I. S. Muzyka ◽

A. I. Miroshnikov ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A

Download Full-text

Epitope specificity plays a critical role in regulating antibody-dependent cell-mediated cytotoxicity against influenza A virus

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1609316113 ◽

2016 ◽

Vol 113 (42) ◽

pp. 11931-11936 ◽

Cited By ~ 88

Author(s):

Wenqian He ◽

Gene S. Tan ◽

Caitlin E. Mullarkey ◽

Amanda J. Lee ◽

Mannie Man Wai Lam ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A Virus ◽

Neutralizing Antibodies ◽

Influenza A ◽

Critical Role ◽

Host Cells ◽

Viral Glycoprotein ◽

Effector Functions ◽

Dependent Cell

The generation of strain-specific neutralizing antibodies against influenza A virus is known to confer potent protection against homologous infections. The majority of these antibodies bind to the hemagglutinin (HA) head domain and function by blocking the receptor binding site, preventing infection of host cells. Recently, elicitation of broadly neutralizing antibodies which target the conserved HA stalk domain has become a promising “universal” influenza virus vaccine strategy. The ability of these antibodies to elicit Fc-dependent effector functions has emerged as an important mechanism through which protection is achieved in vivo. However, the way in which Fc-dependent effector functions are regulated by polyclonal influenza virus-binding antibody mixtures in vivo has never been defined. Here, we demonstrate that interactions among viral glycoprotein-binding antibodies of varying specificities regulate the magnitude of antibody-dependent cell-mediated cytotoxicity induction. We show that the mechanism responsible for this phenotype relies upon competition for binding to HA on the surface of infected cells and virus particles. Nonneutralizing antibodies were poor inducers and did not inhibit antibody-dependent cell-mediated cytotoxicity. Interestingly, anti-neuraminidase antibodies weakly induced antibody-dependent cell-mediated cytotoxicity and enhanced induction in the presence of HA stalk-binding antibodies in an additive manner. Our data demonstrate that antibody specificity plays an important role in the regulation of ADCC, and that cross-talk among antibodies of varying specificities determines the magnitude of Fc receptor-mediated effector functions.

Download Full-text

In vitro and in vivo mechanism of immunomodulatory and antiviral activity of Edible Bird's Nest (EBN) against influenza A virus (IAV) infection

Journal of Ethnopharmacology ◽

10.1016/j.jep.2016.03.020 ◽

2016 ◽

Vol 185 ◽

pp. 327-340 ◽

Cited By ~ 15

Author(s):

Amin Haghani ◽

Parvaneh Mehrbod ◽

Nikoo Safi ◽

Nur Ain Aminuddin ◽

Azadeh Bahadoran ◽

...

Keyword(s):

Antiviral Activity ◽

Influenza A Virus ◽

Influenza A ◽

Edible Bird’S Nest

Download Full-text

Novel Mode of ISG15-Mediated Protection against Influenza A Virus and Sendai Virus in Mice

Journal of Virology ◽

10.1128/jvi.02110-14 ◽

2014 ◽

Vol 89 (1) ◽

pp. 337-349 ◽

Cited By ~ 19

Author(s):

David J. Morales ◽

Kristen Monte ◽

Lulu Sun ◽

Jessica J. Struckhoff ◽

Eugene Agapov ◽

...

Keyword(s):

Tissue Culture ◽

Virus Infection ◽

Influenza A Virus ◽

Virus Replication ◽

Influenza A ◽

Type I Interferon ◽

Sendai Virus ◽

Type I ◽

Induced Genes

ABSTRACTISG15 is a diubiquitin-like modifier and one of the most rapidly induced genes upon type I interferon stimulation. Hundreds of host proteins and a number of viral proteins have been shown to be ISGylated, and understanding how these modifications affect the interferon response and virus replication has been of considerable interest. ISG15−/−mice exhibit increased susceptibility to viral infection, and in the case of influenza B virus and vaccinia virus, ISG15 conjugation has been shown to restrict virus replicationin vivo. A number of studies have also found that ISG15 is capable of antagonizing replication of some viruses in tissue culture. However, recent findings have demonstrated that ISG15 can protect mice from Chikungunya virus infection without affecting the virus burden. In order to better understand the function of ISG15in vivo, we characterized the pathogenesis of influenza A virus and Sendai virus in ISG15−/−mice. We found that ISG15 protects mice from virus induced lethality by a conjugation-dependent mechanism in both of these models. However, surprisingly, we found that ISG15 had minimal effect on virus replication and did not have an obvious role in the modulation of the acute immune response to infection. Instead, we observed an increase in the number of diseased small airways in mice lacking ISG15. This ability of ISG15 to protect mice in a conjugation-dependent, but nonantiviral, manner from respiratory virus infection represents a previously undescribed role for ISG15 and demonstrates the importance of further characterization of ISG15in vivo.IMPORTANCEIt has previously been demonstrated that ISG15−/−mice are more susceptible to a number of viral infections. Since ISG15 is one of the most strongly induced genes after type I interferon stimulation, analysis of ISG15 function has largely focused on its role as an antiviral molecule during acute infection. Although a number of studies have shown that ISG15 does have a small effect on virus replication in tissue culture, few studies have confirmed this mechanism of protectionin vivo. In these studies we have found that while ISG15−/−mice are more susceptible to influenza A virus and Sendai virus infections, ISGylation does not appear to mediate this protection through the direct inhibition of virus replication or the modulation of the acute immune response. Thus, in addition to showing a novel mode of ISG15 mediated protection from virus infection, this study demonstrates the importance of studying the role of ISG15in vivo.

Download Full-text