IL1RL1 and infection: After confirming that ST2 expression was deleted on both splenic and tissue Tregs prior to infection (S3G Fig) we intracranially infected mice with both intact (Foxp3Ert2Cre+/y:: Il1rl1fl/+) and deleted (Foxp3Ert2Cre+/y:: Il1rl1fl/fl) Treg ST2 with ZIKV-Dakar.