TRANSCRIPTION OF THE HUMAN CYTOMEGALOVIRUS NATURAL-KILLER DECOY GENE,UL18, IN-VITRO AND IN-VIVO

Multiplex RT-PCR analysis of human cytomegalovirus (HCMV) replication in human fibroblasts showed transcription of the natural killer (NK) c ell decoy gene, UL18, from 72 h onwards, Transcription of glycoprotein B (gpUL55; a late gene) occurred from early time-points and peaked at 24 h post-infection. UL18 mRNA was also detected in the peripheral bl ood mononuclear cells of organ transplant recipients with HCMV viraemi a, especially those with HCMV DNA virus loads greater than 10(5) genom es/ml whole blood. Thus, UL18 is produced via a low abundance transcri pt late during the infectious cycle at a time coincidental with the in creased risk of NK cell lysis as a consequence of class I HLA down-reg ulation.