Bioinformatic analysis of shared B and T cell epitopes amongst relevant coronaviruses to human health: Is there cross protection?

Within the last 30 years 3 coronaviruses, SARS-CoV, MERS-CoV and SARS-CoV-2, have evolved and adapted to cause disease and spread amongst the human population. From the three, SARS-CoV-2 has spread world-wide and to July 2020 it has been responsible for more than 11 million confirmed cases and over half a million deaths. In the absence of an effective treatment or vaccine, social distancing has been the most effective measure to control the pandemic. However it has become evident that as the virus spreads the only tool that will allow us to fully control it is an effective vaccine. There are currently more than 150 vaccine candidates in different stages of development using a variety of viral antigens, with the S protein being the most targeted antigen. Although some new experimental evidence suggests cross-reacting responses between coronaviruses are present in the population, it remains unknown whether potential shared antigens between different coronaviruses could provide cross-protection. Given that coronaviruses are emerging pathogens and continue to represent a threat to global health, the development of a SARS-Cov-2 vaccine that could provide ‘universal’ protection against other coronaviruses should be pushed forward. Here we present a thorough review of reported B and T cell epitopes shared between SARS-CoV-2 and other relevant coronaviruses, in addition we used web-based tools to predict novel B and T cell epitopes that have not been reported before. Analysis of experimental evidence that is constantly emerging complemented with the findings of this study allow us support the hypothesis that cross-reactive responses, particularly those coming from T cells, might play a key role in controlling infection by SARS-CoV-2. We hope that with the evidence presented in this manuscript we provide arguments to encourage the study of cross-reactive responses in order to elucidate their role in immunity to SARS-CoV-2. Finally we expect our findings will aid targeted analysis of antigen-specific immune responses and guide future vaccine design aiming to develop a cross reactive effective vaccine against respiratory diseases caused by coronaviruses.