Age-associated decline in DNMT1 recruitment by the KIR2DL3 promoter. Chromatin immunoprecipitation of CD158b/j− CD4 and CD8 T cells from 20- to 30-year-old persons (□) and 70- to 85-year-old persons (▩) was performed with antibodies to DNMT1 (A) and DNMT3a (B). Precipitates were analyzed for the presence of KIR2DL3, CD11a, and CD70 promoter sequences. The ratios of DNAspecific IP − DNAcontrol IP to DNAinput are shown as box plots of 7 young (□) and 7 elderly (▩) persons. Transcripts of DNMT1 (C) and DNMT3a (D) in the same donors were quantified by real-time PCR and are shown after normalization for β-actin transcripts. Recruitment of the polycomb protein EZH2 (E) and histone H3 trimethyl Lys27 (F) to the KIR2DL3 promoter was assessed. ChIP assay results of CD158b/j− CD8 T cells are shown as box plots of 6 young (□) and 6 elderly (▩) persons.