Cellular and Humoral Immunogenicity of a Candidate DNA Vaccine Expressing SARS-CoV-2 Spike Subunit 1
Khalid A. Alluhaybi,
Rahaf H. Alharbi,
Rowa Y. Alhabbab,
Najwa D. Aljehani,
Sawsan S. Alamri,
Mohammad Basabrain,
Rehaf Alharbi,
Wesam H. Abdulaal,
Mohamed A. Alfaleh,
Levi Tamming,
Wanyue Zhang,
Mazen Hassanain,
Abdullah Algaissi,
Adel M. Abuzenadah,
Xuguang Li,
Anwar M. Hashem
Affiliations
Khalid A. Alluhaybi
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Rahaf H. Alharbi
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Rowa Y. Alhabbab
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Najwa D. Aljehani
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Sawsan S. Alamri
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Mohammad Basabrain
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Rehaf Alharbi
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Wesam H. Abdulaal
Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Mohamed A. Alfaleh
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Levi Tamming
Centre for Biologics Evaluation, Biologics and Radiopharmaceutical Drug Directorate, Health Products and Food Branch (HPFB), Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON K1A 0K9, Canada
Wanyue Zhang
Centre for Biologics Evaluation, Biologics and Radiopharmaceutical Drug Directorate, Health Products and Food Branch (HPFB), Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON K1A 0K9, Canada
Mazen Hassanain
Department of Surgery, Faculty of Medicine, King Saud University, Riyadh 11451, Saudi Arabia
Abdullah Algaissi
Department of Medical Laboratories Technology, College of Applied Medical Sciences, Jazan University, Jazan 45142, Saudi Arabia
Adel M. Abuzenadah
Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21859, Saudi Arabia
Xuguang Li
Centre for Biologics Evaluation, Biologics and Radiopharmaceutical Drug Directorate, Health Products and Food Branch (HPFB), Health Canada and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Ottawa, ON K1A 0K9, Canada
Anwar M. Hashem
Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21859, Saudi Arabia
The urgent need for effective, safe and equitably accessible vaccines to tackle the ongoing spread of COVID-19 led researchers to generate vaccine candidates targeting varieties of immunogens of SARS-CoV-2. Because of its crucial role in mediating binding and entry to host cell and its proven safety profile, the subunit 1 (S1) of the spike protein represents an attractive immunogen for vaccine development. Here, we developed and assessed the immunogenicity of a DNA vaccine encoding the SARS-CoV-2 S1. Following in vitro confirmation and characterization, the humoral and cellular immune responses of our vaccine candidate (pVAX-S1) was evaluated in BALB/c mice using two different doses, 25 µg and 50 µg. Our data showed high levels of SARS-CoV-2 specific IgG and neutralizing antibodies in mice immunized with three doses of pVAX-S1. Analysis of the induced IgG subclasses showed a Th1-polarized immune response, as demonstrated by the significant elevation of spike-specific IgG2a and IgG2b, compared to IgG1. Furthermore, we found that the immunization of mice with three doses of 50 µg of pVAX-S1 could elicit significant memory CD4+ and CD8+ T cell responses. Taken together, our data indicate that pVAX-S1 is immunogenic and safe in mice and is worthy of further preclinical and clinical evaluation.
