The fCD9 product was amplified further by PCR using 1 fil of the R.A.C.E. reaction as template and the primer F9-2+ and the primer PolyA", 5-TTTATTATGTATCAAATT-GTCTT-3', corresponding to nucleotides 1128 to 1150 of human CD9 (30 cycles at 91 °C for 1 min, 45°C for 1 min and 72°C for 3 min)