RESUMO
The recent outbreak of severe acute respiratory syndrome (SARS) coronavirus (CoV)-2 (SARS-CoV-2) causing coronavirus disease (covid19) has posed a great threat to human health. Previous outbreaks of SARS-CoV and Middle East respiratory Syndrome CoV (MERS-CoV) from the same CoV family had posed similar threat to human health and economic growth. To date, not even a single drug specific to any of these CoVs has been developed nor any anti-viral vaccine is available for the treatment of diseases caused by CoVs. Subunits present in spike glycoproteins of SARS-CoV and SARS-CoV-2 are involved in binding to human ACE2 Receptor which is the primary method of viral invasion. As it has been observed in the previous studies that there are very minor differences in the spike glycoproteins of SARS-CoV and SARS-CoV-2. SARS-CoV-2 has an additional furin cleavage site that makes it different from SARS-CoV (Walls et al., 2020). In this study, we have analyzed spike glycoproteins of SARS-CoV-2 and SARS-CoV phylogenetically and subjected them to selection pressure analysis. Selection pressure analysis has revealed some important sites in SARS-CoV-2 and SARS-CoV spike glycoproteins that might be involved in their pathogenicity. Further, we have developed a potential multi-epitope vaccine candidate against SARS-CoV-2 by analyzing its interactions with HLA-B*15:03 subtype. This vaccine consists of multiple T-helper (TH) cells, B-cells, and Cytotoxic T-cells (CTL) epitopes joined by linkers and an adjuvant to increase its immunogenicity. Conservation of selected epitopes in SARS, MERS, and human hosts, suggests that the designed vaccine could provide cross-protection. The vaccine is designed in silico by following a reverse vaccinology method acknowledging its antigenicity, immunogenicity, toxicity, and allergenicity. The vaccine candidate that we have designed as a result of this work shows promising result indicating its potential capability of simulating an immune response.
