TCRβ and TCRδ gene rearrangements in NK cells. DNA from purified IL-2–activated adult and neonatal NK cells was tested by genomic PCR for TCRβ (A) or TCRδ (B) rearrangement. (A) Genomic PCR using primers specific to Dβ2 and Jβ2.6 genes was analyzed by agarose gel electrophoresis and stained with ethidium bromide. The largest band represents nonrearranged germ line TCRβ locus, whereas multiple smaller bands represent TCRβ gene rearrangements. Thymocyte DNA was used as positive control, and fibroblast DNA was used as negative control. (B) Genomic PCR (Vδ4-Jδ1 or Vδ5-Jδ1) performed with γδT-cell DNA and fibroblast DNA mixed at various ratios and with fresh and IL-2–activated adult and neonatal NK cells. The PCR products were analyzed by agarose gel electrophoresis, blotted, and hybridized to Jδ1-specific oligonucleotide probe. Gels divided by lines are groupings of images from different parts of the same gel.