COVID-19, a global pandemic causing to date more than 50 million cases and more than a million deaths, has to be controlled. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) was identified as the causative agent. Controversy about this virus origin and infectious mechanism for adapting to humans remains a matter for discussion. Among all strategies for obtaining safe and potent vaccines, approaches based on attenuated-killed virus and non-replicating RNA viral vectors are demonstrating promising results. However, specificity of viral components targeted by human antibodies so far has not been demonstrated. A consistent strategy for obtaining functional-active antigens from SARS-CoV-2 specific ligands lead us to propose and test a number of synthetic components. From hundreds of starting sequences only fifteen fulfilled the design requirements and were produced as monomer and polymer forms and immuno-chemically tested. The design was based on worldwide representative reported virus genomes. A bioinformatics scheme by conventional methods and knowledge on MHC-I and II antigen processing mechanisms and HLA haplotype-restriction was performed including sensitive and resistant human populations to virus infection. Covid-19 patients' sera reactivity for synthetic SARS-CoV-2-designed components have proven a high recognition of specific molecules, as well as some evidence for a long-lasting humoral immune response.
Keywords: COVID-19; SARS-CoV-2; antigen design; synthetic-vaccine candidate.