PMID- 36445145 OWN - NLM STAT- MEDLINE DCOM- 20230106 LR - 20230106 IS - 2165-0497 (Electronic) IS - 2165-0497 (Linking) VI - 10 IP - 6 DP - 2022 Dec 21 TI - Generation of an Attenuated Chimeric Bat Influenza A Virus Live-Vaccine Prototype. PG - e0142422 LID - 10.1128/spectrum.01424-22 [doi] LID - e01424-22 AB - Recurring epizootic influenza A virus (IAV) infections in domestic livestock such as swine and poultry are associated with a substantial economic burden and pose a constant threat to human health. Therefore, universally applicable and safe animal vaccines are urgently needed. We recently demonstrated that a reassortment-incompatible chimeric bat H17N10 virus harboring the A/swan/Germany/R65/2006 (H5N1) surface glycoproteins hemagglutinin (HA) and neuraminidase (NA) can be efficiently used as a modified live influenza vaccine (MLIV). To ensure vaccine safety and, thus, improve the applicability of this novel MLIV for mammalian usage, we performed consecutive passaging in eggs and chickens. Following passaging, we identified mutations in the viral polymerase subunits PB2 (I382S), PB1 (Q694H and I695K), and PA (E141K). Strikingly, recombinant chimeric viruses encoding these mutations showed no growth deficiencies in avian cells but displayed impaired growth in human cells and mice. Homologous prime-boost immunization of mice with one of these avian-adapted chimeric viruses, designated rR65(mono)/H17N10(EP18), elicited a strong neutralizing antibody response and conferred full protection against lethal highly pathogenic avian influenza virus (HPAIV) H5N1 challenge infection. Importantly, the insertion of the avian-adaptive mutations into the conventional avian-like A/SC35M/1980 (H7N7) and prototypic human A/PR/8/34 (H1N1) viruses led to attenuated viral growth in human cells and mice. Collectively, our data show that the polymerase mutations identified here can be utilized to further improve the safety of our novel H17N10-based MLIV candidates for future mammalian applications. IMPORTANCE Recurring influenza A virus outbreaks in livestock, particularly in swine and chickens, pose a constant threat to humans. Live attenuated influenza vaccines (LAIVs) might be a potent tool to prevent epizootic outbreaks and the resulting human IAV infections; however, LAIVs have several disadvantages, especially in terms of reassortment with circulating IAVs. Notably, the newly identified bat influenza A viruses H17N10 and H18N11 cannot reassort with conventional IAVs. Chimeric bat influenza A viruses encoding surface glycoproteins of conventional IAV subtypes might thus function as safe and applicable modified live influenza vaccines (MLIVs). FAU - Ran, Wei AU - Ran W AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. FAU - Schon, Jacob AU - Schon J AD - Institute of Diagnostic Virology, Friedrich Loeffler Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany. FAU - Ciminski, Kevin AU - Ciminski K AUID- ORCID: 0000-0001-5397-7497 AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. FAU - Kraft, Julian AU - Kraft J AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. FAU - Kessler, Susanne AU - Kessler S AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. FAU - Euchner, Sophie AU - Euchner S AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. FAU - Hoffmann, Donata AU - Hoffmann D AD - Institute of Diagnostic Virology, Friedrich Loeffler Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany. FAU - Pohlmann, Anne AU - Pohlmann A AD - Institute of Diagnostic Virology, Friedrich Loeffler Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany. FAU - Beer, Martin AU - Beer M AUID- ORCID: 0000-0002-0598-5254 AD - Institute of Diagnostic Virology, Friedrich Loeffler Institute, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany. FAU - Schwemmle, Martin AU - Schwemmle M AUID- ORCID: 0000-0002-2972-6855 AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. FAU - Giese, Sebastian AU - Giese S AUID- ORCID: 0000-0001-6215-5743 AD - Institute of Virology, University Medical Center Freiburg, Freiburg, Germany. AD - Faculty of Medicine, University of Freiburg, Freiburg, Germany. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20221129 PL - United States TA - Microbiol Spectr JT - Microbiology spectrum JID - 101634614 RN - 0 (Antibodies, Viral) RN - 0 (Hemagglutinin Glycoproteins, Influenza Virus) RN - 0 (Influenza Vaccines) SB - IM MH - Animals MH - Mice MH - Antibodies, Viral MH - Chickens MH - *Chiroptera/virology MH - Hemagglutinin Glycoproteins, Influenza Virus/genetics MH - *Influenza A virus/genetics MH - *Influenza Vaccines/genetics MH - *Orthomyxoviridae Infections/prevention & control PMC - PMC9769755 OTO - NOTNLM OT - bat influenza A virus OT - influenza A virus OT - modified live influenza vaccine COIS- The authors declare no conflict of interest. EDAT- 2022/11/30 06:00 MHDA- 2022/12/28 06:00 PMCR- 2022/11/29 CRDT- 2022/11/29 09:13 PHST- 2022/11/30 06:00 [pubmed] PHST- 2022/12/28 06:00 [medline] PHST- 2022/11/29 09:13 [entrez] PHST- 2022/11/29 00:00 [pmc-release] AID - 01424-22 [pii] AID - spectrum.01424-22 [pii] AID - 10.1128/spectrum.01424-22 [doi] PST - ppublish SO - Microbiol Spectr. 2022 Dec 21;10(6):e0142422. doi: 10.1128/spectrum.01424-22. Epub 2022 Nov 29.