Agradecimentos: We thank Florian Krammer from Icahn School of Medicine, Mount Sinai, New York, NY, U.S.A., and Gary R. Whittaker from the Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, U.S.A. for donating the plasmids. This work was supported by grants from the National Council for Scientific and Technological Development (CNPq Grant ID 130843/2020-2 to HHMC and 440812/2016-0 to CRP), Ministry of Health, Special Health Fund for Mass Immunization and Disease Control of the State Department of Health of the State of São Paulo (FESIMA), Coordination for the Improvement of Higher Education Personnel (CAPES Grant ID 88887.703323/2022-00 to HHMC, 88881.130804/2016–01 to CRP and 88887.506965/2020–0 to ML) and the São Paulo Research Foundation (FAPESP Grant ID 17/50333-7 to CRP) Ver menos

Abstract: Neutralizing antibodies (nAbs) are a critical part of coronavirus disease 2019 (COVID-19) research as they are used to gain insight into the immune response to severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infections. Among the technologies available for generating nAbs, DNA-based immunization methods are an alternative to conventional protocols. In this pilot study, we investigated whether DNA-based immunization by needle injection in rabbits was a viable approach to produce a functional antibody response. We demonstrated that three doses of DNA plasmid carrying the gene encoding the full-length spike protein (S) or the receptor binding domain (RBD) of SARS-CoV-2 induced a time-dependent increase in IgG antibody avidity maturation. Moreover, the IgG antibodies displayed high cross neutralization by live SARS-CoV-2 and pseudoviruses neutralization assays. Thus, we established a simple, low cost and feasible DNA-based immunization protocol in rabbits that elicited high IgG avidity maturation and nAbs production against SARS-CoV-2, highlighting the importance of DNA-based platforms for developing new immunization strategies against SARS-CoV-2 and future emerging epidemics Ver menos