Biology subjects

Hemmi, S.

Publications and source records attributed to Hemmi, S..

3 recordsLinked to original sources

bioRxiv2021

A single oral immunization with a replication-competent adenovirus-vectored vaccine protects mice from influenza respiratory infection

The development of effective and flexible vaccine platforms is a major public health challenge as recently highlighted by the COVID-19 pandemic. Adenoviruses (AdVs) are easy to produce and have a good safety and efficacy profile when administered orally as demonstrated by the long-term use of oral AdV 4 and 7 vaccines in the US military. These viruses therefore appear to be the ideal backbone for the development of oral replicative vector vaccines. However, research on these vaccines is limited by the ineffective replication of human AdVs in laboratory animals. The use of mouse AdV type 1 (MAV-1) in its natural host allows infection to be studied under replicative conditions. Here, we orally vaccinated mice with MAV-1 vectors expressing the full length or the "headless" hemagglutinin (HA) of influenza to assess the protection conferred against an intranasal challenge of influenza. We showed that while the headless HA vector did not generate a significant humoral or cellular immune response to influenza, a single oral immunisation with the full-length HA vaccine generated influenza-specific and neutralizing antibodies and completely protected the mice against clinical signs and viral replication. ImportanceGiven the constant threat of pandemics and the need for annual vaccination against influenza and possibly emerging agents such as SARS-CoV-2, new types of vaccines that are easier to produce and administer and therefore more widely accepted are a critical public health need. Here, using a relevant animal model, we have shown that replicative oral AdV vaccine vectors can help make vaccination against major respiratory diseases more available, better accepted and therefore more effective. These results could be of major importance in the coming years in the fight against emerging diseases such as COVID-19.

microbiology↗

bioRxiv2020

The E3 ubiquitin ligase Mind bomb 1 enhances nuclear import of viral DNA by inactivating a virion linchpin protein that suppresses exposure of virion pathogen-associated molecular patterns

In eukaryotic cells, genomes from incoming DNA viruses mount two opposing reactions, viral gene expression and innate immune response, depending on genome exposure (uncoating) to either RNA-polymerases or DNA sensors. Here we show that adenovirus particles contain a tunable linchpin protein with a dual function: response to host cues for scheduled DNA release into the nucleus, and innate immunity suppression by preventing unscheduled DNA release. Scheduled DNA release required the proteasome and ubiquitination of the viral core protein V. Cells lacking the E3 ligase Mind bomb 1 (Mib1) were resistant to wild-type adenovirus infection. Viruses lacking protein V or bearing non-ubiquitinable protein V, however, readily infected Mib1 knockout cells, yet were less infectious than wild-type virus. Their genomes were poorly imported into the nucleus and remained uncoated in the cytosol, thereby enhancing chemokine and interferon production through the DNA sensor cGAS. Our data uncover how the ubiquitin-proteasome system controls the function of a virion linchpin protein suppressing pathogen-associated molecular patterns and triggers viral DNA uncoating at the nuclear pore complex for nuclear import and infection.

microbiology↗

bioRxiv2020

The FDA-approved drug Nelfinavir inhibits lytic cell-free transmission of human adenoviruses

Adenoviruses (AdVs) are prevalent and give rise to chronic and recurrent disease. The human AdV (HAdV) species B and C, such as HAdV-C2, C5 and B14, cause respiratory disease, and constitute a health threat for immuno-compromised individuals. HAdV-Cs are well known for lysing cells, owing to the E3 CR1-{beta}-encoded adenovirus death protein (ADP). We previously reported a high-throughput image-based screening framework and identified an inhibitor of HAdV-C2 multi-round infection, Nelfinavir Mesylate. Nelfinavir is the active ingredient of Viracept, an FDA-approved inhibitor of the human immuno-deficiency virus (HIV) aspartyl protease, and used to treat acquired immunodeficiency syndrome (AIDS). It is not effective against single round HAdV infections. Here, we show that Nelfinavir inhibits the lytic cell-free transmission of HAdV, indicated by the suppression of comet-shaped infection foci in cell culture. Comet-shaped foci occur upon convection-based transmission of cell-free viral particles from an infected cell to neighbouring uninfected cells. HAdV lacking ADP was insensitive to Nelfinavir, but gave rise to comet-shaped foci indicating that ADP enhances but is not required for cell lysis. This was supported by the notion that HAdV-B14 and B14p1 lacking ADP were highly sensitive to Nelfinavir, although HAdV-A31, B3, B7, B11, B16, B21, D8, D30 or D37 were less sensitive. Conspicuously, Nelfinavir uncovered slow-growing round-shaped HAdV-C2 foci, independent of neutralizing antibodies in the medium, indicative of non-lytic cell-to-cell transmission. Our study demonstrates the repurposing potential of Nelfinavir with post-exposure efficacy against different HAdVs, and describes an alternative non-lytic cell-to-cell transmission mode of HAdV. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=181 SRC="FIGDIR/small/098061v1_ufig1.gif" ALT="Figure 1"> View larger version (85K): org.highwire.dtl.DTLVardef@8aa32corg.highwire.dtl.DTLVardef@1dea943org.highwire.dtl.DTLVardef@13aa2fborg.highwire.dtl.DTLVardef@a23352_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO C_FIG

microbiology↗