The defective pTreg recruitment to the site of infection in BATF3-/- mice could not be attributed to a differential composition of the microbiota of WT and BATF3-/- mice, as co-housing the mice from birth until the study endpoint produced the same results, i.e. a selective defect in the recruitment of pTregs expressing Tbet and RORγt to the site of infection (suppl Fig 4I–4M). The gene discussed is TBX21; the disease is infection.