Agarose gel electrophoresis of RT-PCR-amplified sequences specific for HIgR plus PRR-1 (HIgR + PRR-1) (A), HIgR (B), PRR-1 (C), HveA(HVEM) (D), and β-actin (E). Sequences were amplified from cDNAs of the indicated cells (A to E) and from appropriate plasmids (A to D) or from cellular DNA (E). Each panel shows the intensity of amplified bands for increasing amounts of target sequences, as follows. (A) Lanes a to c and d to f contain 50, 500, and 5,000 copies of pLX1.12 (PRR-1) and pCF18 (HIgR), respectively. (B) Lanes d to f contain 5, 50, and 500 copies of pCF18. (C) Lanes d to f contain 50, 500, and 5,000 copies of pLX1.12. (D) Lanes d to f contain 50, 500, and 5,000 copies of pBEC10 for HveA. (E) Lanes g to i contain 0.1, 1, or 10 ng of DNA from human T lymphocytes. Lane M, molecular weight markers. Lanes mock, negative reaction controls lacking DNA but containing all other reagents. The sizes of the amplified products were 269, 119, 184, 233, and 674 bp for HIgR+PRR-1, HIgR, PRR-1, HveA, and β-actin, respectively. HF, MRC human fibroblasts.