Frequency of CD8(+) T lymphocytes specific for lytic and latent antigens of Epstein-Barr virus in healthy virus carriers

We investigated CD8(+) T cell frequencies of five different Epstein-Barr vi rus-specific cytotoxic T lymphocyte epitopes located within proteins of the replicative cycle and the latent state in healthy long-term Virus carriers with IFN-gamma enzyme-linked immunospot assay. Frequencies of the HLA-A3-r estricted epitope RVRAYTYSK (RVR) whose minimal length was mapped in this s tudy to amino acid position 148-156 of the immediate-early protein BRLF1 we re compared with those of a further known HLA-A3-restricted epitope within EBNA3A, RLRAEAQVK (RLR). Determination of frequencies of CD8(+) T lymphocyt es directed against lytic antigen epitope RVR revealed that only one of eig ht donors recognized this epitope. Frequency was calculated to be 65 RVR-sp ecific CD8(+) T lymphocytes per 10(6) PBMC. None of the HLA-A3-positive don ors exhibited IFN-gamma release after antigenic stimulation with the EBNA3A -specific peptide epitope RLR. Furthermore, we chose three known HLA-B8-res tricted epitopes, RAKFKQLL (RAK), FLRGRAYGL (FLR), and QAKWRLQTL (QAK), of the lytic protein BZLF1 and the latent protein EBNA3A. Examination of eight HLA-BB-positive virus carriers revealed that the BZLF1-specific epitope RA K was recognized by all donors with a median frequency of 233 RAK-specific CD8(+) T lymphocytes per 10(6) PBMC. Only 50% of these donors reacted again st EBNA3A-specific epitope FLR and a minority (25%) reacted against EBNA3A- specific epitope QAK. (C) 1999 Academic Press.