At five days post secondary infection, Treg and CD4+ conventional T (Tcon) cells that were lung tissue residents exhibited the highest percentages of NP311-325 tetramer bound fractions (Supplemental Figure 3B, left column), although, by number, there were more NP311-325 -specific CD4+ Tcon cells observed in the spleen (Supplemental Figure 3B, middle column); at this time, NP311-325 -specific lung tissue resident Treg cells had expanded ~6 fold (Supplemental Figure 3B, right column) similar to the lung tissue resident Treg population as a whole (Figure 5C). The gene discussed is CD4; the disease is infection.