CDS CTL from genital herpes simplex lesions: Recognition of viral tegumentand immediate early proteins and lysis of infected cutaneous cells

HSV-2 causes chronic infections, CDS CTL may play several protective roles, and stimulation of a CD8 response is a rational element of vaccine design for this pathogen, The viral Ags recognized by CD8 T cells are largely unkn own. It has been hypothesized that HSV inhibition of TAP may favor recognit ion of virion input proteins or viral immediate early proteins. We tested t his prediction using HSV-specific CD8 CTL clones obtained from genital HSV- 2 lesions. Drug and replication block experiments were consistent with spec ificity for the above-named classes of viral proteins, Fine specificity was determined by expression cloning using molecular libraries of viral DNA, a nd peptide epitopes recognized at nanomolar concentrations were identified. Three of four clones recognized the viral tegument proteins encoded by gen es UL47 and UL49, These proteins are transferred into the cytoplasm on viru s entry. Processing of the tegument Ag-derived epitopes was TAP dependent. The tegument-specific CTL were able to lyse HLA class I-appropriate fibrobl asts after short times of infection. Lysis of keratinocytes required longer infection and pretreatment with IFN-gamma, Another clone recognized an imm ediate early protein, ICP0, Lymphocytes specific for these lesion-defined e pitopes could be reactivated from the PBMC of additional subjects. These da ta are consistent with an influence of HSV immune evasion genes upon the se lection of proteins recognized by CD8 CTL in lesions. Tegument proteins, id entified for the first time as Ags recognized by HSV-specific CD8 CTL, are rational candidate vaccine compounds.