Ly9 regulates the size of the peripheral NKT1 cell pool. (A) Intracellular staining of PLZF, RORγt and T-Bet in spleen iNKT cells (CD1d tetramer+ B220-) from 11-week-old BALB/c or BALB/c.Ly9−/− mice. Numbers indicate the frequency of each subset among total iNKT cells in the spleen. (B) Percentage and (C) number of splenic iNKT subsets in 11-week-old BALB/c or BALB/c.Ly9−/− mice (n=10/group). (D) Percentage and (E) absolute number of splenic NKT1, NKT2, and NKT17 subsets in 11-week-old B6 (n=16) or B6.Ly9−/− (n=14) mice. (F) Representative staining of virtual memory (VM) CD8+ T cells (CD44hi Eomeshi) in gated CD3+ CD8+ splenocytes from BALB/c or BALB/c.Ly9−/− mice. (G) Percentage of VM CD8+ T cells in spleens from 11-week-old BALB/c or BALB/c.Ly9−/− mice (n=9/group). (H) Representative staining of VM CD8+ T cells (CD44hi Eomeshi) in gated CD3+ CD8+ splenocytes from B6 or B6.Ly9−/− mice. (I) Percentage of VM CD8+ T cells in spleens from 11-week-old B6 (n=16) or B6.Ly9−/− (n=14) mice. (B, D, G, I) Each dot represents an individual mouse. Small horizontal lines indicate the mean. (C, E) Results are expressed as mean ± SD. **p <0.01; ***p <0.001 (unpaired two-tailed t-test). Data are pooled from at least two independent experiments with 3–6 mice per group.