Suchergebnisse

Self-amplifying RNA replicons are promising platforms for vaccine generation. Their defects in one or more essential functions for viral replication, particle assembly, or dissemination make them highly safe as vaccines. We previously showed that the deletion of the envelope (E) gene from the Middle East respiratory syndrome coronavirus (MERS-CoV) produces a replication-competent propagation- defective RNA replicon (MERS-CoV-ΔE). Evaluation of this replicon in mice expressing human dipeptidyl peptidase 4, the virus receptor, showed that the single deletion of the E gene generated an attenuated mutant. The combined deletion of the E gene with accessory open reading frames (ORFs) 3, 4a, 4b, and 5 resulted in a highly attenuated propagation-defective RNA replicon (MERS-CoV-Δ[3,4a,4b,5,E]). This RNA replicon induced sterilizing immunity in mice after challenge with a lethal dose of a virulent MERS-CoV, as no histopathological damage or infectious virus was detected in the lungs of challenged mice. The four mutants lacking the E gene were genetically stable, did not recombine with the E gene provided in trans during their passage in cell culture, and showed a propagation-defective phenotype in vivo. In addition, immunization with MERS-CoV-Δ[3,4a,4b,5,E] induced significant levels of neutralizing antibodies, indicating that MERS-CoV RNA replicons are highly safe and promising vaccine candidates ; Government of Spain and European Union co-financed grant BIO2016-75549-R; by Government of Spain grants PID2019-107001RB-I00, Proyecto Intramural Especial (PIE) 202020E079, and PIE–Consejo Superior de Investigaciones Científicas (CSIC) 202020E043; by European Commission grants ZAPI_IMI_JU_115760, ISOLDA_848166, and MANCO_101003651; and by IH grant 2P01AI060699

Viroporins are viral proteins with ion channel (IC) activity that play an important role in several processes, including virus replication and pathogenesis. While many coronaviruses (CoVs) encode two viroporins, severe acute respiratory syndrome CoV (SARS-CoV) encodes three: proteins 3a, E, and 8a. Additionally, proteins 3a and E have a PDZ-binding motif (PBM), which can potentially bind over 400 cellular proteins which contain a PDZ domain, making them potentially important for the control of cell function. In the present work, a comparative study of the functional motifs included within the SARS-CoV viroporins was performed, mostly focusing on the roles of the IC and PBM of E and 3a proteins. ; This work was supported by grants from the Government of Spain (BIO2013-42869-R and BIO2016-75549-R AEI/FEDER, UE), the European Zoonotic Anticipation and Preparedness Initiative (ZAPI) (IMI_JU_115760), and the U.S. National Institutes of Health (NIH) (0258-3413/HHSN266200700010C awarded to L.E., 2P01AI060699 awarded to L.E. and S.P., and R01 AI129269 awarded to S.P.). V.M.A. and M.Q.M. are grateful for the support of the Government of Spain (FIS2013-40473-P and FIS2016-75257-P AEI/FEDER, UE) and Universitat Jaume I (P1.1B2015-28). C.C.R. received a contract from Fundación La Caixa.