Flow cytometry and statistical analysis.

Flow cytometry data acquisition was performed with an LSR-II flow cytometer (BD Biosciences). Data were analyzed as described above using FlowJo 8.8.4 software (TreeStar, Ashland, OR). Statistical analyses were conducted using GraphPad Prism 7 software. The specific test for each analysis is listed in the figure legends. In most cases, an ordinary two-way analysis of variance (ANOVA) was used, followed by post hoc analysis with Sidak’s multiple-comparison test (when a set of means was selected to compare) or Tukey’s test (where there was an unequal sample size or the means were compared against every other mean). For pairwise comparisons, an unpaired t test with Welch’s correction was used. Differences between groups was considered significant when P < 0.05.