Optimization in the expression of ASFV proteins for the development of subunit vaccines using poxviruses as delivery vectors.

Authors: JAIME, LOPERA-MADRID - University Of Wisconsin; LEX, MEDINA MAGUES - University Of Wisconsin; Gladue, Douglas; Borca, Manuel; JORGE, OSORIO - University Of Wisconsin

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2021
Publication Date: 12/6/2021
Citation: Jaime, L., Lex, M., Gladue, D.P., Borca, M.V., Jorge, O. 2021. Optimization in the expression of ASFV proteins for the development of subunit vaccines using poxviruses as delivery vectors. Scientific Reports. https://doi.org/10.1038/s41598-021-02949-x.
DOI: https://doi.org/10.1038/s41598-021-02949-x

Interpretive Summary: African swine fever virus (ASFV) causes a devastating disease in swine, called African swine fever (ASF), that is currently spreading across Europe and Asia. There are several experimental live-attenuated vaccines for ASF, however some of them have residual effects and require additional changes to increase safety. Here we evaluate the use for a another virus (called MVA) used as a vector to deliver proteins of ASFV. This is a necessary first step evaluate the potential use of MVA as vector for future ASF vaccines.

Technical Abstract: African swine fever virus (ASFV) causes a highly contagious hemorrhagic disease that affects domestic pig and Eurasian wild boar populations. To date, no safe and efficacious treatment or vaccine against ASF is available. Nevertheless, there are several reports of protection elicited by experimental vaccines based on live attenuated ASFV and some levels of protection and reduced viremia in other approaches such as DNA, adenovirus, baculovirus, and vaccinia-based vaccines. Current ASF subunit vaccine research focuses mainly on delivering protective antigens and antigen discovery within the ASFV genome. However, due to the complex nature of ASFV, expression vectors need to be optimized to improve their immunogenicity. Therefore, in the present study, we constructed several recombinant MVA vectors to evaluate the efficiency of different promoters and secretory signal sequences in the expression and immunogenicity of the p30 protein from ASFV. Overall, the natural poxvirus PrMVA13.5L promoter induced high levels of both p30 mRNA and specific anti-p30 antibodies in mice. In contrast, the synthetic PrS5E promoter and the S E/L promoter linked to a secretory signal showed lower mRNA levels and antibodies. These findings indicate that promoter selection may be as important as the antigen used in the development of ASFV subunit vaccines using MVA as the delivery vector.