Figure 1.

Flow cytometric gating technique used to identify CD8⁺CD28^null natural killer T-like (NKT-like) cells (and CD8⁺CD28⁺ NKT-like cells) from the peripheral blood of patients with chronic obstructive pulmonary disease. (A) Identification of lymphocytes as CD45⁺ low side scatter (SSC) events. (B) Removal of red blood cell contaminations removed by lymphocyte gating using forward scatter vs. SSC characteristics. (C) Identification of NKT-like cells as CD3⁺CD56⁺ events. (D) Identification of CD28^null and CD28⁺ NKT-like cells using CD8 vs. CD28 staining. (E) Expression of IFNγ and histone deacetylase (HDAC)2 in CD8⁺CD28^null and CD8⁺CD28⁺ cells. (F) Expression of P-glycoprotein-1 (Pgp1), glucocorticoid receptor (GCR), and heat shock protein (Hsp)90 expression in CD8⁺CD28^null and CD8⁺CD28⁺ cells. Note: the majority of NKT-like cells are CD8⁺ and CD28^null. These cells express reduced HDAC2, GCR, and Hsp90 but increased IFNγ compared with CD8⁺CD28⁺ NKT-like cells (Pgp1 unchanged).