Recognition of human cytomegalovirus gene products by HCMV-specific cytotoxic T cells

The antigen specificity of HCMV-specific cytotoxic T cells (CTL) was investigated in healthy adult seropositive donors by analyzing the frequency of CTL precursors (CTL(p)) against six different HCMV-encoded proteins. HCMV-specific, CD8(+) CTL clones from two donors were also characterized. The precursor frequency analysis showed that a major phosphoprotein of HCMV, pp65 (UL83), was the immunodominant CTL target antigen in healthy seropositive adults. The frequency of CTL(p) specific for different HCMV proteins ranged from 1/12,000 for pp65 to >1/100,000 for gB (UL55), gH (UL75), pp50 (UL44), and pp28 (UL98). Characterization of the HCMV-specific CTL clones from two donors revealed that the majority of clones lysed targets expressing pp65 and that none of the clones recognized other HCMV proteins. (C) 1996 Academic Press. Inc.