Long-lasting cross-protection against influenza A by neuraminidase and M2e-based immunization strategies

There is mounting evidence that in the absence of neutralizing antibodies cross-reactive T cells provide protection against pandemic influenza viruses. Here, we compared protection and CD8+ T cell responses following challenge with H1N1 2009 pandemic and H3N2 viruses of mice that had been immunized with hemagglutinin (HA), neuraminidase (NA) and the extracellular domain of matrix protein 2 (M2e) fused to a virus-like particle (VLP). Mice were challenged a first time with a sublethal dose of H1N1 2009 pandemic virus and, four weeks later, challenged again with an H3N2 virus. Mice that had been vaccinated with HA, NA, NA + M2e-VLP and HA + NA + M2e-VLP were protected against homologous H1N1 virus challenge. Challenged NA and NA + M2e-VLP vaccinated mice mounted CD8+ T cell responses that correlated with protection against secondary H3N2 challenge. HA-vaccinated mice were fully protected against challenge with homologous H1N1 2009 virus, failed to mount cross-reactive CD8+ T cells and succumbed to the second challenge with heterologous H3N2 virus. In summary, NA- and M2e-based immunity can protect against challenge with (homologous) virus without compromising the induction of robust cross-reactive CD8+ T cell responses upon exposure to virus

Potential recombinant vaccine against influenza A virus based on M2e displayed on nodaviral capsid nanoparticles

Influenza A virus poses a major threat to human health, causing outbreaks from time to time. Currently available vaccines employ inactivated viruses of different strains to provide protection against influenza virus infection. However, high mutation rates of influenza virus hemagglutinin (H) and neuraminidase (N) glycoproteins give rise to vaccine escape mutants. Thus, an effective vaccine providing protection against all strains of influenza virus would be a valuable asset. The ectodomain of matrix 2 protein (M2e) was found to be highly conserved despite mutations of the H and N glycoproteins. Hence, one to five copies of M2e were fused to the carboxyl-terminal end of the recombinant nodavirus capsid protein derived from Macrobrachium rosenbergii. The chimeric proteins harboring up to five copies of M2e formed nanosized virus-like particles approximately 30 nm in diameter, which could be purified easily by immobilized metal affinity chromatography. BALB/c mice immunized subcutaneously with these chimeric proteins developed antibodies specifically against M2e, and the titer was proportional to the copy numbers of M2e displayed on the nodavirus capsid nanoparticles. The fusion proteins also induced a type 1 T helper immune response. Collectively, M2e displayed on the nodavirus capsid nanoparticles could provide an alternative solution to a possible influenza pandemic in the future

Super-resolution microscopy reveals significant impact of M2e-specific monoclonal antibodies on influenza A virus filament formation at the host cell surface

Influenza A virions are highly pleomorphic, exhibiting either spherical or filamentous morphology. The influenza A virus strain A/Udorn/72 (H3N2) produces copious amounts of long filaments on the surface of infected cells where matrix protein 1(M1) and 2 (M2) play a key role in virus filament formation. Previously, it was shown that an anti-M2 ectodomain (M2e) antibody could inhibit A/Udorn/72 virus filament formation. However, the study of these structures is limited by their small size and complex structure. Here, we show that M2e-specific IgG1 and IgG2a mouse monoclonal antibodies can reduce influenza A/Udorn/72 virus plaque growth and infectivity in vitro. Using Immuno-staining combined with super-resolution microscopy that allows us to study structures beyond the diffraction limit, we report that M2 is localized at the base of viral filaments that emerge from the membrane of infected cells. Filament formation was inhibited by treatment of A/Udorn/72 infected cells with M2e-specific IgG2a and IgG1 monoclonal antibodies and resulted in fragmentation of pre-existing filaments. We conclude that M2e-specific IgGs can reduce filamentous influenza A virus replication in vitro and suggest that in vitro inhibition of A/Udorn/72 virus replication by M2e-specific antibodies correlates with the inhibition of filament formation on the surface of infected cells

Vaccination induced antibodies to recombinant avian influenza a virus M2 protein or synthetic M2e peptide do not bind to the M2 protein on the virus or virus infected cells.

BACKGROUND: Influenza viruses are characterized by their highly variable surface proteins HA and NA. The third surface protein M2 is a nearly invariant protein in all Influenza A strains. Despite extensive studies in other animal models, this study is the first to describe the use of recombinant M2 protein and a peptide coding for the extracellular part of the M2 protein (M2e) to vaccinate poultry. METHODS: Four groups of layer chickens received a prime-boost vaccination with recombinant M2 protein, M2e, a tetrameric construct from M2e peptide bound to streptavidin and a control tetrameric construct formulated with Stimune adjuvant. RESULTS: We determined the M2-specific antibody (Ab) responses in the serum before vaccination, three weeks after vaccination and two weeks after booster, at days 21, 42 and 56 of age. The group vaccinated with the M2 protein in combination with Stimune adjuvant showed a significant Ab response to the complete M2 protein as compared to the other groups. In addition an increased Ab response to M2e peptide was found in the group vaccinated with the M2e tetrameric construct. None of the vaccinated animals showed seroconversion to AI in a commercial ELISA. Finally no Ab’s were found that bound to M2 expressed on in vitro AI infected MDCK cells. CONCLUSION: Although Ab’s are formed against the M2 protein and to Streptavidin bound M2e peptide in a tetrameric conformation these Ab’s do not recognize of M2 on the virus or on infected cells

Oblique Corrections in the MSSM at One Loop. I. Scalars

This paper is devoted to reconsider the one-loop oblique corrections arising from the scalar superpartners in the MSSM, i.e, the squarks, the sleptons and the scalars in Higgs sector. We explicitly present the complete one-loop forms of self-energy corrections to the gauge bosons of SM electroweak gauge groups, as well as their descendants the $S$, $T$ and $U$ parameters, which can be directly applied to constrain the parameter space of the MSSM. Our results about one-loop self energies are found to agree with Drees, Hagiwara, and Yamada (1992), Pierce et al. (1997). Nevertheless, the $S$, $T$ and $U$ parameters aren't in agreement with Dobado, Herrero and Penaranda (1999).Comment: short version to appear in Advances in High Energy Physic

Single-photon signals at LEP in supersymmetric models with a light gravitino

We study the single-photon signals expected at LEP in models with a very light gravitino. The dominant process is neutralino-gravitino production (e+e- -> chi+ G) with subsequent neutralino decay via chi->gamma+G, giving a gamma+E_miss signal. We first calculate the cross section at arbitrary center-of-mass energies and provide new analytic expressions for the differential cross section valid for general neutralino compositions. We then consider the constraints on the gravitino mass from LEP 1 and LEP161 single-photon searches, and possible such searches at the Tevatron. We show that it is possible to evade the stringent LEP 1 limits and still obtain an observable rate at LEP 2, in particular in the region of parameter space that may explain the CDF e+e+gamma+gamma+E_T,miss event. As diphoton events from neutralino pair-production would not be kinematically accessible in this scenario, the observation of whichever photonic signal will discriminate among the various light-gravitino scenarios in the literature. We also perform a Monte Carlo simulation of the expected energy and angular distributions of the emitted photon, and of the missing invariant mass expected in the events. Finally we specialize the results to the case of a recently proposed one-parameter no-scale supergravity model.Comment: 31 pages, LaTeX, 14 figures (included

Scattering for massive Dirac fields on the Kerr metric

Starting with the Dirac equation outside the event horizon of a non-extreme Kerr black hole, we develop a time-dependent scattering theory for massive Dirac particles. The explicit computation of the modified wave operators at infinity is done by implementing a time-dependent logarithmic phase shift from the free dynamics to offset the long range term in the full Hamiltonian due to the presence of the gravitational force. Analytical expressions for the wave operators are also given.Comment: 33 pages, 1 figure, new proof of Lemma III.1, minor changes in Section III, a few typos corrected in Thm. IV.1 and Thm. B.

Sparticle spectrum and constraints in anomaly mediated supersymmetry breaking models

We study in detail the particle spectrum in anomaly mediated supersymmetry breaking models in which supersymmetry breaking terms are induced by the super-Weyl anomaly. We investigate the minimal anomaly mediated supersymmetry breaking models, gaugino assisted supersymmetry breaking models, as well as models with additional residual nondecoupling D-term contributions due to an extra U(1) gauge symmetry at a high energy scale. We derive sum rules for the sparticle masses in these models which can help in differentiating between them. We also obtain the sparticle spectrum numerically, and compare and contrast the results so obtained for the different types of anomaly mediated supersymmetry breaking models.Comment: LaTeX, 20 pages, 6 figures. A few comments and a reference added; typos corrected; version published in Phys. Rev.

Standard Model Decays of Tau into Three Charged Leptons

Analytic expressions are given for the $\tau$ decays into three charged leptons, \tau\rta \ell\ell\overline \ell\nu_\tau\overline \nu_\ell, where the $\ell$ are combinations of electrons and muons, and for the radiative decays \tau\rta \gamma\ell\nu_\tau\overline \nu_\ell. The branching ratios are sensitive functions of whether the final state $\ell$ are muons or electrons.Comment: 11 pages Latex, CPP-93-30, SMU-HEP-94/02. Postscript files for figures appended in compressed for