“…Our results presented herein further support that an increased basal frequency of Tregs in the circulation correlates with protection both from early SARS-CoV viral replication, as well as from disease upon infection ( Figures 2 and 4 ). In the context of multiple viral infections, we and others have found that Tregs are critical to orchestrate proper anti-viral immune responses ( Lanteri et al, 2009 ; Lund et al, 2008 ; Pattacini et al, 2016 ; Ruckwardt et al, 2009 ; Soerens et al, 2016 ), while it has also been found that Tregs in the context of infections, including respiratory infections such as RSV and influenza, can assist in protecting the host from excessive immunopathology ( Belkaid and Tarbell, 2009 ; Brincks et al, 2013 ; Lee et al, 2010 ; Loebbermann et al, 2012 ; Richert-Spuhler and Lund, 2015 ; Smigiel et al, 2014 ). Thus, our results here further support the concept that balance between anti-viral immunity and immunoregulation is essential to spare the host from both unrestricted viral replication as well as severe disease after infection.…”