RT-PCR analysis of total RNA extracted from transfected Vero cells. RT-PCR analysis of the transfected Vero cells showed the presence of IL-15 and IL-18 transcripts in the transfected cell lysate. The products were resolved in 2% (w/v) agarose gel in TAE. M: 100 bp DNA ladder (Promega, Madison WI); (a) Lane 1 to 3: IL-15 transcript (126 bp), Lane 4 to 6: IL-18 transcript (161 bp). (b) No specific band was observed when RNAs were analyzed by PCR without the RT part as in Lane 7 to 9: IL-15 and Lane 10 to 12: IL-18.