Figure 1. PD-1 deficiency increases CD4⁺ T cell activation in hypercholesterolemic mice.

a) Circulating numbers of CD4⁺ T cells in Ldlr^{− /−} or Ldlr^{− /−} Pd1^{− /−} mice after 9 weeks of high fat diet feeding. b-d) Representative FACS dot plots showing CD44 and CD62L expression in pre-gated CD45⁺CD3⁺TCRβ⁺ CD4⁺ T cells and quantitation of frequencies of CD44^hiCD62L⁻ effector/memory cells among CD4⁺ T cells in blood (b), spleen (c) and peripheral LN (d) after 9 weeks of high fat diet feeding (n = 5/group, representative of 2 independent experiments). **p<0.01.