AUTHOR=Clerici Mario TITLE=Understanding the Struggle Between Viruses and the Immune System: A Quintessential Grand Challenge JOURNAL=Frontiers in Virology VOLUME=1 YEAR=2021 URL=https://www.frontiersin.org/journals/virology/articles/10.3389/fviro.2021.671745 DOI=10.3389/fviro.2021.671745 ISSN=2673-818X