Potential Role of Nonneutralizing IgA Antibodies in Cross-Protective Immunity against Influenza A Viruses of Multiple Hemagglutinin Subtypes

ABSTRACT IgA antibodies on mucosal surfaces are known to play an important role in protection from influenza A virus (IAV) infection and are believed to be more potent than IgG for cross-protective immunity against IAVs of multiple hemagglutinin (HA) subtypes. However, in general, neutralizing antibodies specific to HA are principally HA subtype specific. Here, we focus on nonneutralizing but broadly cross-reactive HA-specific IgA antibodies. Recombinant IgG, monomeric IgA (mIgA), and polymeric secretory IgA (pSIgA) antibodies were generated based on the sequence of a mouse anti-HA monoclonal antibody (MAb) 5A5 that had no neutralizing activity but showed broad binding capacity to multiple HA subtypes. While confirming that there was no neutralizing activity of the recombinant MAbs against IAV strains A/Puerto Rico/8/1934 (H1N1), A/Adachi/2/1957 (H2N2), A/Hong Kong/483/1997 (H5N1), A/shearwater/South Australia/1/1972 (H6N5), A/duck/England/1/1956 (H11N6), and A/duck/Alberta/60/1976 (H12N5), we found that pSIgA, but not mIgA and IgG, significantly reduced budding and release of most of the viruses from infected cells. Electron microscopy demonstrated that pSIgA deposited newly produced virus particles on the surfaces of infected cells, most likely due to tethering of virus particles. Furthermore, we found that pSIgA showed significantly higher activity to reduce plaque sizes of the viruses than IgG and mIgA. These results suggest that nonneutralizing pSIgA reactive to multiple HA subtypes may play a role in intersubtype cross-protective immunity against IAVs. IMPORTANCE Mucosal immunity represented by pSIgA plays important roles in protection from IAV infection. Furthermore, IAV HA-specific pSIgA antibodies are thought to contribute to cross-protective immunity against multiple IAV subtypes. However, the mechanisms by which pSIgA exerts such versatile antiviral activity are not fully understood. In this study, we generated broadly cross-reactive recombinant IgG and pSIgA having the same antigen-recognition site and compared their antiviral activities in vitro. These recombinant antibodies did not show “classical” neutralizing activity, whereas pSIgA, but not IgG, significantly inhibited the production of progeny virus particles from infected cells. Plaque formation was also significantly reduced by pSIgA, but not IgG. These effects were seen in infection with IAVs of several different HA subtypes. Based on our findings, we propose an antibody-mediated host defense mechanism by which mucosal immunity may contribute to broad cross-protection from IAVs of multiple HA subtypes, including viruses with pandemic potential.

Download Full-text

A Novel Mechanism Underlying Antiviral Activity of an Influenza Virus M2-Specific Antibody

Journal of Virology ◽

10.1128/jvi.01277-20 ◽

2020 ◽

Vol 95 (1) ◽

Author(s):

Rashid Manzoor ◽

Nao Eguchi ◽

Reiko Yoshida ◽

Hiroichi Ozaki ◽

Tatsunari Kondoh ◽

...

Keyword(s):

Antiviral Activity ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Influenza A ◽

Binding Capacity ◽

Vaccine Antigen ◽

Progeny Virus ◽

M2 Protein ◽

Specific Antibodies ◽

Infected Cells

ABSTRACT Protective immunity against influenza A viruses (IAVs) generally depends on antibodies to the major envelope glycoprotein, hemagglutinin (HA), whose antigenicity is distinctive among IAV subtypes. On the other hand, the matrix 2 (M2) protein is antigenically highly conserved and has been studied as an attractive vaccine antigen to confer cross-protective immunity against multiple subtypes of IAVs. However, antiviral mechanisms of M2-specific antibodies are not fully understood. Here, we report the molecular basis of antiviral activity of an M2-specific monoclonal antibody (MAb), rM2ss23. We first found that rM2ss23 inhibited A/Aichi/2/1968 (H3N2) (Aichi) but not A/PR/8/1934 (H1N1) (PR8) replication. rM2ss23 altered the cell surface distribution of M2, likely by cross-linking the molecules, and interfered with the colocalization of HA and M2, resulting in reduced budding of progeny viruses. However, these effects were not observed for another strain, PR8, despite the binding capacity of rM2ss23 to PR8 M2. Interestingly, HA was also involved in the resistance of PR8 to rM2ss23. We also found that two amino acid residues at positions 54 and 57 in the M2 cytoplasmic tail were critical for the insensitivity of PR8 to rM2ss2. These findings suggest that the disruption of the M2-HA colocalization on infected cells and subsequent reduction of virus budding is one of the principal mechanisms of antiviral activity of M2-specific antibodies and that anti-M2 antibody-sensitive and -resistant IAVs have different properties in the interaction between M2 and HA. IMPORTANCE Although the IAV HA is the major target of neutralizing antibodies, most of the antibodies are HA subtype specific, restricting the potential of HA-based vaccines. On the contrary, the IAV M2 protein has been studied as a vaccine antigen to confer cross-protective immunity against IAVs with multiple HA subtypes, since M2 is antigenically conserved. Although a number of studies highlight the protective role of anti-HA neutralizing and nonneutralizing antibodies, precise information on the molecular mechanism of action of M2-specific antibodies is still obscure. In this study, we found that an anti-M2 antibody interfered with the HA-M2 association, which is important for efficient budding of progeny virus particles from infected cells. The antiviral activity was IAV strain dependent despite the similar binding capacity of the antibody to M2, and, interestingly, HA was involved in susceptibility to the antibody. Our data provide a novel mechanism underlying antiviral activity of M2-specific antibodies.

Download Full-text

Particle Assembly and Ultrastructural Features Associated with Replication of the Lytic Archaeal Virus Sulfolobus Turreted Icosahedral Virus

Journal of Virology ◽

10.1128/jvi.02668-08 ◽

2009 ◽

Vol 83 (12) ◽

pp. 5964-5970 ◽

Cited By ~ 73

Author(s):

Susan K. Brumfield ◽

Alice C. Ortmann ◽

Vincent Ruigrok ◽

Peter Suci ◽

Trevor Douglas ◽

...

Keyword(s):

Time Course ◽

Plaque Assay ◽

Ultrastructural Changes ◽

Progeny Virus ◽

Particle Assembly ◽

Virus Particles ◽

Transmission Electron ◽

Archaeal Viruses ◽

Infected Cells ◽

Sulfolobus Turreted Icosahedral Virus

ABSTRACT Little is known about the replication cycle of archaeal viruses. We have investigated the ultrastructural changes of Sulfolobus solfataricus P2 associated with infection by Sulfolobus turreted icosahedral virus (STIV). A time course of a near synchronous STIV infection was analyzed using both scanning and transmission electron microscopy. Assembly of STIV particles, including particles lacking DNA, was observed within cells, and fully assembled STIV particles were visible by 30 h postinfection (hpi). STIV was determined to be a lytic virus, causing cell disruption beginning at 30 hpi. Prior to cell lysis, virus infection resulted in the formation of pyramid-like projections from the cell surface. These projections, which have not been documented in any other host-virus system, appeared to be caused by the protrusion of the cell membrane beyond the bordering S-layer. These structures are thought to be sites at which progeny virus particles are released from infected cells. Based on these observations of lysis, a plaque assay was developed for STIV. From these studies we propose an overall assembly model for STIV.

Download Full-text

Ontogenesis of the formation of secretory antibodies to respiratory syncytial (RS) virus

Epidemiology and Infection ◽

10.1017/s0950268800029435 ◽

1988 ◽

Vol 101 (3) ◽

pp. 565-575 ◽

Cited By ~ 3

Author(s):

N. P Leschinskaya ◽

E. E Pokrovskaya ◽

E. A Kantorovitch ◽

S.K Grigorjeva ◽

YA. S Shvartsman

Keyword(s):

Old Age ◽

Serum Antibody ◽

Close Correlation ◽

Secretory Iga ◽

Igg Antibodies ◽

Virus Infections ◽

Neutralizing Activity ◽

Iga Antibodies ◽

Antibody Levels ◽

Secretory Antibodies

SUMMARYExamination of sera from 184 children aged between 0 and 12 years and 161 adults revealed a close correlation between age and the level of humoral anti-RS virus immunity. Secretory IgG antibodies were found in children in their first months of life. Evidence for their release into secretions from the serum was obtained. This might explain the positive correlation between serum antibody levels in women recently confined with the morbidity due to RS virus in children during their first months of life. Secretory IgA antibodies were found from 4 months untill old age. The secretions of children and adults contained virus-neutralizing activity which was non-immunoglobulin in nature, as well as antibodies. However, in contrast to secretory antibody this material did not prevent development of severe RS virus infections.

Download Full-text

Human MxA Protein Inhibits the Replication of Crimean-Congo Hemorrhagic Fever Virus

Journal of Virology ◽

10.1128/jvi.78.8.4323-4329.2004 ◽

2004 ◽

Vol 78 (8) ◽

pp. 4323-4329 ◽

Cited By ~ 78

Author(s):

Ida Andersson ◽

Linda Bladh ◽

Mehrdad Mousavi-Jazi ◽

Karl-Eric Magnusson ◽

Åke Lundkvist ◽

...

Keyword(s):

Antiviral Activity ◽

Hemorrhagic Fever ◽

Inhibitory Effect ◽

Fever Virus ◽

Progeny Virus ◽

Crimean Congo Hemorrhagic Fever ◽

Viral Genomes ◽

Virus Particles ◽

Hemorrhagic Fever Virus ◽

Infected Cells

ABSTRACT Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to the genus Nairovirus within the family Bunyaviridae and is the causative agent of severe hemorrhagic fever. Despite increasing knowledge about hemorrhagic fever viruses, the factors determining their pathogenicity are still poorly understood. The interferon-induced MxA protein has been shown to have an inhibitory effect on several members of the Bunyaviridae family, but the effect of MxA against CCHFV has not previously been studied. Here, we report that human MxA has antiviral activity against CCHFV. The yield of progeny virus in cells constitutively expressing MxA was reduced up to 1,000-fold compared with control cells, and accumulation of viral genomes was blocked. Confocal microscopy revealed that MxA colocalizes with the nucleocapsid protein (NP) of CCHFV in the perinuclear regions of infected cells. Furthermore, we found that MxA interacted with NP by using a coimmunoprecipitation assay. We also found that an amino acid substitution (E645R) within the C-terminal domain of MxA resulted in a loss of MxA antiviral activity and, concomitantly, in the capacity to interact with CCHFV NP. These results suggest that MxA, by interacting with a component of the nucleocapsid, prevents replication of CCHFV viral RNA and thereby inhibits the production of new infectious virus particles.

Download Full-text

The Morphology and Composition of Influenza A Virus Particles Are Not Affected by Low Levels of M1 and M2 Proteins in Infected Cells

Journal of Virology ◽

10.1128/jvi.79.12.7926-7932.2005 ◽

2005 ◽

Vol 79 (12) ◽

pp. 7926-7932 ◽

Cited By ~ 28

Author(s):

Svetlana V. Bourmakina ◽

Adolfo García-Sastre

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Virus Particles ◽

M1 Protein ◽

Infected Cells ◽

Low Levels ◽

Viral Components

ABSTRACT We generated a recombinant influenza A virus (Mmut) that produced low levels of matrix (M1) and M2 proteins in infected cells. Mmut virus propagated to significantly lower titers than did wild-type virus in cells infected at low multiplicity. By contrast, virion morphology and incorporation of viral proteins and vRNAs into virus particles were similar to those of wild-type virus. We propose that a threshold amount of M1 protein is needed for the assembly of viral components into an infectious particle and that budding is delayed in Mmut virus-infected cells until sufficient levels of M1 protein accumulate at the plasma membrane.

Download Full-text

Development of a copper-graphene nanocomposite based transparent coating with antiviral activity against influenza virus

10.1101/2020.09.02.279737 ◽

2020 ◽

Author(s):

Indrani Das Jana ◽

Partha Kumbhakar ◽

Saptarshi Banerjee ◽

Chinmayee Chowde Gowda ◽

Nandita Kedia ◽

...

Keyword(s):

Antiviral Activity ◽

Influenza A ◽

Respiratory Infections ◽

Transmission Rate ◽

Viral Gene Expression ◽

Progeny Virus ◽

Viral Gene ◽

Virus Particles ◽

Transparent Coating ◽

Virion Particles

AbstractRespiratory infections by RNA viruses are one of the major burdens upon global health and economy. Viruses like influenza or coronaviruses can be transmitted through respiratory droplets or contaminated surfaces. An effective antiviral coating can decrease the viability of the virus particles in the outside environment significantly, hence reducing their transmission rate. In this work, we have screened a series of nanoparticles and their composites for antiviral activity using Nano Luciferase based highly sensitive influenza A reporter virus. Using this screening system, we have identified copper-graphene (Cu-Gr) nanocomposite shows strong antiviral activity. Extensive material and biological characterization of the nanocomposite suggested a unique metal oxide embedded graphene sheet architecture that can inactivate the virion particles only within 30 minutes of pre-incubation and subsequently interferes with the entry of these virion particles into the host cell. This ultimately results in reduced viral gene expression, replication and production of progeny virus particles, slowing down the overall pace of progression of infection. Using PVA as a capping agent, we have been able to generate a Cu-Gr nanocomposite based highly transparent coating that retains its original antiviral activity in the solid form.

Download Full-text

Comparative Analyses of the Antiviral Activities of IgG and IgA Antibodies to Influenza A Virus M2 Protein

Viruses ◽

10.3390/v12070780 ◽

2020 ◽

Vol 12 (7) ◽

pp. 780

Author(s):

Kosuke Okuya ◽

Nao Eguchi ◽

Rashid Manzoor ◽

Reiko Yoshida ◽

Shinji Saito ◽

...

Keyword(s):

Influenza A Virus ◽

Envelope Protein ◽

Influenza A ◽

Viral Envelope ◽

Progeny Virus ◽

Gel Chromatography ◽

M2 Protein ◽

Igg Antibody ◽

Iga Antibodies ◽

Antiviral Activities

The influenza A virus (IAV) matrix-2 (M2) protein is an antigenically conserved viral envelope protein that plays an important role in virus budding together with another envelope protein, hemagglutinin (HA). An M2-specific mouse monoclonal IgG antibody, rM2ss23, which binds to the ectodomain of the M2 protein, has been shown to be a non-neutralizing antibody, but inhibits plaque formation of IAV strains. In this study, we generated chimeric rM2ss23 (ch-rM2ss23) IgG and IgA antibodies with the same variable region and compared their antiviral activities. Using gel chromatography, ch-rM2ss23 IgA were divided into three antibody subsets: monomeric IgA (m-IgA), dimeric IgA (d-IgA), and trimeric and tetrameric IgA (t/q-IgA). We found that t/q-IgA had a significantly higher capacity to reduce the plaque size of IAVs than IgG and m-IgA, most likely due to the decreased number of progeny virus particles produced from infected cells. Interestingly, HA-M2 colocalization was remarkably reduced on the infected cell surface in the presence of ch-rM2ss23 antibodies. These results indicate that anti-M2 polymeric IgA restricts IAV budding more efficiently than IgG and suggest a role of anti-M2 IgA in cross-protective immunity to IAVs.

Download Full-text

Relationship of the quaternary structure of human secretory IgA to neutralization of influenza virus

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1503885112 ◽

2015 ◽

Vol 112 (25) ◽

pp. 7809-7814 ◽

Cited By ~ 48

Author(s):

Tadaki Suzuki ◽

Akira Kawaguchi ◽

Akira Ainai ◽

Shin-ichi Tamura ◽

Ryo Ito ◽

...

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Influenza A ◽

High Speed ◽

Influenza Virus Infection ◽

Secretory Iga ◽

Upper Respiratory Tract ◽

Influenza A Viruses ◽

Iga Antibodies ◽

Quaternary Structures

Secretory IgA (S-IgA) antibodies, the major contributors to humoral mucosal immunity to influenza virus infection, are polymeric Igs present in many external secretions. In the present study, the quaternary structures of human S-IgA induced in nasal mucosa after administration of intranasal inactivated influenza vaccines were characterized in relation to neutralization potency against influenza A viruses. Human nasal IgA antibodies have been shown to contain at least five quaternary structures. Direct and real-time visualization of S-IgA using high-speed atomic force microscopy (AFM) demonstrated that trimeric and tetrameric S-IgA had six and eight antigen-binding sites, respectively, and that these structures exhibited large-scale asynchronous conformational changes while capturing influenza HA antigens in solution. Furthermore, trimeric, tetrameric, and larger polymeric structures, which are minor fractions in human nasal IgA, displayed increased neutralizing potency against influenza A viruses compared with dimeric S-IgA, suggesting that the larger polymeric than dimeric forms of S-IgA play some important roles in protection against influenza A virus infection in the human upper respiratory tract.

Download Full-text

Rab11a mediates cell-cell spread and reassortment of influenza A virus genomes via tunneling nanotubes

10.1101/2021.01.20.427426 ◽

2021 ◽

Author(s):

Ketaki Ganti ◽

Julianna Han ◽

Balaji Manicassamy ◽

Anice C. Lowen

Keyword(s):

Influenza A ◽

Tunneling Nanotubes ◽

Viral Genomes ◽

Virus Particles ◽

Donor Cells ◽

Infected Cells ◽

Spread Of Infection ◽

Viral Components ◽

Cell Spread ◽

Cell Cell

AbstractInfluenza A virus (IAV) genomes comprise eight negative strand RNAs packaged into virions in the form of viral ribonucleoproteins (vRNPs). Rab11a plays a crucial role in the transport of vRNPs from the nucleus to the plasma membrane via microtubules, allowing assembly and virus production. Here, we identify a novel function for Rab11a in the inter-cellular transport of IAV vRNPs using tunneling nanotubes (TNTs) as molecular highways. TNTs are F-Actin rich tubules that link the cytoplasms of nearby cells. In IAV-infected cells, Rab11a was visualized together with vRNPs in these actin-rich intercellular connections. To better examine viral spread via TNTs, we devised an infection system in which conventional, virion-mediated, spread was not possible. Namely, we generated HA-deficient reporter viruses which are unable to produce progeny virions but whose genomes can be replicated and trafficked. In this system, vRNP transfer to neighboring cells was observed and this transfer was found to be dependent on both actin and Rab11a. Generation of infectious virus via TNT transfer was confirmed using donor cells infected with HA-deficient virus and recipient cells stably expressing HA protein. Mixing donor cells infected with genetically distinct IAVs furthermore revealed the potential for Rab11a and TNTs to serve as a conduit for genome mixing and reassortment in IAV infections. These data therefore reveal a novel role for Rab11a in the IAV life cycle, which could have significant implications for within-host spread, genome reassortment and immune evasion.Author SummaryInfluenza A viruses infect epithelial cells of the upper and lower respiratory tract in humans. Infection is propagated by the generation of viral particles from infected cells, which disseminate within the tissue. Disseminating particles can encounter obstacles in the extracellular environment, including mucus, ciliary movement, antibody neutralization and uptake by phagocytic immune cells. An alternative mode of spread, which avoids these hazards, involves direct transport of viral components between cells. This cell-cell spread of infection is not a well understood process. In this study we demonstrate that the host factor Rab11a mediates the transport of viral genomes in the cell-cell spread of infection. Rab11a is already known to play a pro-viral role in the transport of viral genomes to the plasma membrane for assembly into virus particles. Here, we see that this same transport mechanism is co-opted for direct cell-cell spread through cellular connections called tunneling nanotubes. We show that complexes of Rab11a and viral components can be trafficked across tunneling nanotubes, transmitting infection without the formation of virus particles. Importantly, this route of spread often seeds viral genomes from multiple donor cells into recipient cells, which in turn increases viral genetic diversity.

Download Full-text

Parallel evolution between genomic segments of seasonal human influenza viruses reveals RNA-RNA relationships

10.1101/2021.01.14.426718 ◽

2021 ◽

Author(s):

Jennifer E. Jones ◽

Valerie Le Sage ◽

Gabriella H. Padovani ◽

Michael Calderon ◽

Erik S. Wright ◽

...

Keyword(s):

Influenza A ◽

Parallel Evolution ◽

Nuclear Periphery ◽

Influenza Viruses ◽

Progeny Virus ◽

Selective Assembly ◽

Human Influenza ◽

Virus Particles ◽

Before And After ◽

Negative Sense

AbstractThe influenza A virus (IAV) genome consists of eight negative-sense viral RNA (vRNA) segments that are selectively assembled into progeny virus particles through RNA-RNA interactions. To identify relationships between vRNA segments, we examined parallel evolution between vRNA segments of seasonal human IAV, finding that evolutionary relationships between vRNA segments differ between subtypes and antigenically-shifted strains. Intersegmental relationships were distinct between H3N2 and H1N1 viruses, but largely conserved over time in H3N2 viruses. However, parallel evolution of vRNA segments diverged between H1N1 strains isolated before and after the 2009 pandemic. Surprisingly, intersegmental relationships were not driven solely by protein sequence, which is potentially indicative of RNA-RNA driven coevolution. Colocalization of highly coevolved vRNA segments was enriched over other pairs at the nuclear periphery during a productive viral infection. This study illustrates how phylogenetics can be applied to interrogate putative RNA interactions underlying selective assembly of IAV.

Download Full-text