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J Mol Biol ; 434(6): 167277, 2022 03 30.
Article in English | MEDLINE | ID: covidwho-2061566


Establishment of the interferon (IFN)-mediated antiviral state provides a crucial initial line of defense against viral infection. Numerous genes that contribute to this antiviral state remain to be identified. Using a loss-of-function strategy, we screened an original library of 1156 siRNAs targeting 386 individual curated human genes in stimulated microglial cells infected with Zika virus (ZIKV), an emerging RNA virus that belongs to the flavivirus genus. The screen recovered twenty-one potential host proteins that modulate ZIKV replication in an IFN-dependent manner, including the previously known IFITM3 and LY6E. Further characterization contributed to delineate the spectrum of action of these genes towards other pathogenic RNA viruses, including Hepatitis C virus and SARS-CoV-2. Our data revealed that APOL3 acts as a proviral factor for ZIKV and several other related and unrelated RNA viruses. In addition, we showed that MTA2, a chromatin remodeling factor, possesses potent flavivirus-specific antiviral functions induced by IFN. Our work identified previously unrecognized genes that modulate the replication of RNA viruses in an IFN-dependent manner, opening new perspectives to target weakness points in the life cycle of these viruses.

Flavivirus , Interferons , Virus Replication , Apolipoproteins L/genetics , Apolipoproteins L/metabolism , Flavivirus/physiology , Histone Deacetylases/genetics , Histone Deacetylases/metabolism , Humans , Interferons/genetics , Membrane Proteins/genetics , Membrane Proteins/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism , SARS-CoV-2/physiology , Zika Virus/physiology
EBioMedicine ; 75: 103810, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1634471


BACKGROUND: V591 (TMV-083) is a live recombinant measles vector-based vaccine candidate expressing a pre-fusion stabilized SARS-CoV-2 spike protein. METHODS: We performed a randomized, placebo-controlled Phase I trial with an unblinded dose escalation and a double-blind treatment phase at 2 sites in France and Belgium to evaluate the safety and immunogenicity of V591. Ninety healthy SARS-CoV-2 sero-negative adults (18-55 years of age) were randomized into 3 cohorts, each comprising 24 vaccinees and 6 placebo recipients. Participants received two intramuscular injections of a low dose vaccine (1 × 105 median Tissue Culture Infectious Dose [TCID50]), one or two injections of a high dose vaccine (1 × 106 TCID50), or placebo with a 28 day interval. Safety was assessed by solicited and unsolicited adverse events. Immunogenicity was measured by SARS-CoV-2 spike protein-binding antibodies, neutralizing antibodies, spike-specific T cell responses, and anti-measles antibodies., NCT04497298. FINDINGS: Between Aug 10 and Oct 13, 2020, 148 volunteers were screened of whom 90 were randomized. V591 showed a good safety profile at both dose levels. No serious adverse events were reported. At least one treatment-related adverse event was reported by 15 (20.8%) participants receiving V591 vs. 6 (33.3%) of participants receiving placebo. Eighty-one percent of participants receiving two injections of V591 developed spike-binding antibodies after the second injection. However, neutralizing antibodies were detectable on day 56 only in 17% of participants receiving the low dose and 61% receiving the high dose (2 injections). Spike-specific T cell responses were not detected. Pre-existing anti-measles immunity had a statistically significant impact on the immune response to V591, which was in contrast to previous results with the measles vector-based chikungunya vaccine. INTERPRETATION: While V591 was generally well tolerated, the immunogenicity was not sufficient to support further development. FUNDING: Themis Bioscience GmbH, a subsidiary of Merck & Co. Inc., Kenilworth, NJ, USA; Coalition for Epidemic Preparedness Innovations (CEPI).

COVID-19 Vaccines/administration & dosage , COVID-19/immunology , Genetic Vectors , Immunogenicity, Vaccine , Measles virus , SARS-CoV-2/immunology , Adolescent , Adult , COVID-19/genetics , COVID-19/prevention & control , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Double-Blind Method , Female , Humans , Male , Middle Aged , SARS-CoV-2/genetics
Cell Host Microbe ; 29(2): 236-249.e6, 2021 02 10.
Article in English | MEDLINE | ID: covidwho-978240


To develop a vaccine candidate against coronavirus disease 2019 (COVID-19), we generated a lentiviral vector (LV) eliciting neutralizing antibodies against the Spike glycoprotein of SARS-CoV-2. Systemic vaccination by this vector in mice, in which the expression of the SARS-CoV-2 receptor hACE2 has been induced by transduction of respiratory tract cells by an adenoviral vector, confers only partial protection despite high levels of serum neutralizing activity. However, eliciting an immune response in the respiratory tract through an intranasal boost results in a >3 log10 decrease in the lung viral loads and reduces local inflammation. Moreover, both integrative and non-integrative LV platforms display strong vaccine efficacy and inhibit lung deleterious injury in golden hamsters, which are naturally permissive to SARS-CoV-2 replication and closely mirror human COVID-19 physiopathology. Our results provide evidence of marked prophylactic effects of LV-based vaccination against SARS-CoV-2 and designate intranasal immunization as a powerful approach against COVID-19.

Administration, Intranasal/methods , COVID-19 Vaccines/administration & dosage , COVID-19/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , Cricetinae , Female , Genetic Vectors , Immunity, Mucosal , Immunization, Secondary , Immunoglobulin A/immunology , Lentivirus/genetics , Lentivirus/immunology , Male , Mice , Models, Animal , Respiratory System/immunology , Spike Glycoprotein, Coronavirus/immunology , Viral Load