Phenotypic markers of the KIL cell line. (A) Flow cytometric analysis of the expression of Ly5.1 (CD45), CD3, NK1.1, CD25, CD4, CD8, CD19, and Mac-1. Open curve indicates isotype control. (B) Nested PCR analyses of D-J rearrangements of TCRβ loci. Genomic DNAs of W20 stromal fibroblasts (negative control),¹²  B6D2F1 spleen cells (positive control), and KIL were first amplified using external primer sets (Dβ1.1ext/Jβ1.7ext or Dβ2.1ext/Jβ2.7ext) and then re-amplified using internal primer sets (Dβ1.1int/Jβ1.7int or Dβ2.1int/Jβ2.7int). Aliquots of secondary PCR reactions were run on agarose gels and stained with ethidium bromide. DNA fragments resulting from amplification of the germline loci are indicated. (C) The same blots in panel B were probed with P³²-labeled Dβ1.1-Jβ1.7 or Dβ2.1-Jβ2.7 probes. All DNAs amplified from the germ-line and rearranged D-J loci hybridize specifically to the respective probe.