Detection of UL138 RNA in hematopoietic cells isolated from seropositive donors. (A) RNA isolated from CD34⁺ cells of seropositive (lanes 1-5) or seronegative (lanes 6-8) donors was analyzed by RT-PCR for (i) UL138, (iii) IE1, and (iv) GAPDH gene expression. RNA was amplified in panel ii with no prior RT. (B) RNA isolated from peripheral blood monocytes of seropositive (lanes 4, 6, 7, 9, and 11) or seronegative (lanes 1-3, 5, 8, 10, 12, 13) donors was analyzed by RT-PCR for (i) UL138, (iii) IE1, and (iv) GAPDH gene expression. RNA was also amplified in panel ii with no prior RT. (C) RNA isolated from CD34⁺ cells (lanes 1, 2, 5, 6) and CD34-derived dendritic cells (DDCs) (lanes 3, 4, 7, 8) of 2 further seropositive donors was analyzed by RT-PCR (lanes 1-4) for (i) UL138, (ii) IE1, and (iii) GAPDH gene expression. RNA was also amplified in an (i) UL138-PCR and (ii) with no prior RT (lanes 5-8). In all experiments, PCR products were transferred to a nitrocellulose membrane and probed with internal sequences to UL138 and IE1 genes.