Background: Several vaccines in the world are commercialized for COVID-19 infection. One of these vaccines is inactivated SARS-CoV-2 vaccine which is formulated in Alum adjuvant that is not capable of the induction of cellular immune responses. In the present study, inactivated SARS CoV-2 virus was formulated in AS03 adjuvant and the immunogenicity was compared with the Alum-based vaccine. Methods: Experimental 6-8-week-old BALB/c mice were immunized three times at three weeks intervals with AS03- and Alum-based vaccines along with PBS as a control group. Lymphocyte proliferation of spleen cells was performed by the BrdU method, IL-4 and IFN-γ cytokines were assessed on the spleen cell culture supernatant by quantitative ELISA kits. Specific total IgG and IgG1/IgG2a were assessed with an optimized indirect ELISA. Results: The results showed that the vaccine formulated in AS03 adjuvant led to a significant lymphocyte proliferation response versus Alum-based and PBS control group. Conclusion: In addition, the cytokines responses showed a Th1 platform in our vaccine formulation. Furthermore, IgG response showed an improvement versus the other experimental groups.
