Chimeric hPIV2/Corona-Spike Nasal Vaccine Robustly Protects the Upper and Lower Airways Against SARS-CoV-2

Abstract

We developed an intranasal vaccine against SARS-CoV-2 using the replication-incompetent human parainfluenza virus type 2 (hPIV2) vector BC-PIV, which can deliver ectopic gene as stable RNA and ectopic protein on the envelope. BC-PIV expressing the full-length prefusion-stabilized spike gene of SARS-CoV-2, S2PM, possessed a corona-like viral envelope. Intranasal vaccination of mice with BC-PIV/S2PM induced high levels of neutralizing IgG and mucosal IgA antibodies against the spike protein. While BC-PIV showed hemagglutinating activity, BC-PIV/S2PM lacked such activity, in accordance with the presence of the massive spike protein on the viral surface. Furthermore, single-dose intranasal vaccination of hamsters with BC-PIV/S2PM completely protected the lungs from SARS-CoV-2 at 11 weeks post-immunization, and prime-boost vaccination conferred virtually complete protection of the nasal turbinates against SARS-CoV-2 challenge at 11 weeks post-priming. Thus, this chimeric hPIV2/spike intranasal vaccine is one of the strong candidates for an ultimate vaccine against SARS-CoV-2 to curtail virus transmission.Funding: This work was supported in part by Grants-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology in Japan (17K19652, 20K21614), by a Research Program on Emerging and Re-emerging Infectious Diseases from the Japan Agency for Medical Research and Development (AMED) (JP19fk0108113), Mie University (for research institutes of excellence), Mie Prefecture, Junior Chamber International Yokkaichi, and MediciNova, Inc.Conflict of Interest: J.O., M.F., M.Im., R.O., S.Y., Y.Kaw., and T.N. are patent applicants for recombinant BCPIV vaccine against SARS-CoV-2. M.F. is a founder of BioComo, Inc., and J.O. is an employee of BioComo, Inc. J.O., M.F., M.M., and T.N. have shares of stock in Biocomo, Inc. M.M. is a scientific advisor of JEOL Ltd. T.N. is a scientific advisor of MediciNova, Inc. The other authors declare no competing interests.Ethical Approval: Recombinant DNA experiments with SARS-CoV-2 S gene fragments were approved by the Ministry of Education, Culture, Sports, Science and Technology in Japan (Approved No. 2019-728, 729; 2020-362, 373, 948). The animal studies were approved by the Animal Care Committees of Mie University(Approved No. 23-33) and the Animal Experiment Committee of the Institute of Medical Science, the University of Tokyo (Approved No. PA19-75), and all methods were performed under institutional regulations of animal experiments in accordance with the current national guidelines. Animal experiments using SARS-CoV-2 S gene fragments orSARS-CoV-2 were also approved by the Ministry of Education, Culture, Sports, Science and Technology in Japan (Approved No. 2019-728, 729; 2020-362, 373, 2020-948).