AICL expression by human NK cell lines. Expression of AICL by human cell lines probed by flow cytometry, quantitative PCR (qPCR), and immunoblotting. (A) Cell surface expression of AICL (upper) by human NK cell lines (NK3.3, NK-92MI, NKL, YT) and other human cell lines (U937, Mono Mac6, Jurkat, K562, HeLa, 293) was assessed by flow cytometric analysis using anti-AICL mAb 7F12 (open histograms). For detection of total AICL protein, cells were permeabilized prior to incubation with 7F12 (lower). Isotype control stainings are shown in gray. (B) Levels of AICL transcripts in human cell lines. Relative levels of AICL transcripts in cell lines (including the primate cell line COS-7) were determined by qPCR and set relative to levels of NKL (arbitrarily set as 1). Means of triplicates are shown with standard deviations. (C) Total AICL protein in human cell lines as determined by immunoblotting. Cell lysates (same samples as in panel A) were separated by SDS-PAGE under reducing conditions and, after blotting, probed with anti-AICL mAb 7G4. For U937, signals after shorter exposure are also shown. Actin detection served as loading control. (A-C) One representative experiment out of 3 is shown.