Development of a vaccine against Coronavirus SARS-CoV-2 using a new antigen presenting system

Abstract

The recent worldwide SARS-CoV-2 Coronavirus epidemic calls for coordinated efforts by the scientific community to develop new diagnostic tests, new treatments and the development of vaccines. The effort for the development of vaccines has focused on modifications of technologies that were already under development for other similar viruses, such as the Coronavirus SARS-CoV-1, MERS, and even Influenza. The most important ones today are based on DNA vaccines, other attenuated viruses, nanoparticles and mRNA presenting the SARS-CoV-2 antigens. Many of these strategies take into account the importance of the particulate nature for the proper stimulation of the immune system. The present project proposes to use a new antigen presentation system based on the coupling of recombinant antigens to a matrix of external membrane vesicles (OMVs) with high built-in adjuvant power, for the constitution of a highly immunogenic molecular complex, APS-OMV -rAg. This platform was developed in our laboratories and is part of a patent application in the process of submission to the INPI. The results obtained with the expression of Schistosoma mansoni antigens in this system demonstrated that the induced humoral immune response is in the order of 100 times greater than the same antigen administered with aluminum hydroxide. In addition, the isotype profile indicates a more balanced immune response with a strong cellular response component (thesis Barbosa, 2020). Our expectation is that the presentation of SARS-CoV-2 antigens on this platform will induce a high humoral immune response, capable of neutralizing the virus. The dual, particle/adjuvant character of the complex may induce a higher immune response than strategies involving different forms of nanoparticles. In addition, OMVs are already used as adjuvants in commercial vaccines and there is a lot of experience in expression of recombinant proteins, therefore, it would be a technology whose main steps are implanted in the industry, allowing easy scaling for industrial production. (AU)