Frequency of CD8+ T Lymphocytes Specific for Lytic and Latent Antigens of Epstein–Barr Virus in Healthy Virus Carriers

Abstract

We investigated CD8(+) T cell frequencies of five different Epstein-Barr virus-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-restricted epitope RVRAYTYSK (RVR) whose minimal length was mapped in this study to amino acid position 148-156 of the immediate-early protein BRLF1 were compared with those of a further known HLA-A3-restricted epitope within EBNA3A, RLRAEAQVK (RLR). Determination of frequencies of CD8(+) T lymphocytes directed against lytic antigen epitope RVR revealed that only one of eight donors recognized this epitope. Frequency was calculated to be 65 RVR-specific CD8(+) T lymphocytes per 10(6) PBMC. None of the HLA-A3-positive donors exhibited IFN-gamma release after antigenic stimulation with the EBNA3A-specific peptide epitope RLR. Furthermore, we chose three known HLA-B8-restricted epitopes, RAKFKQLL (RAK), FLRGRAYGL (FLR), and QAKWRLQTL (QAK), of the lytic protein BZLF1 and the latent protein EBNA3A. Examination of eight HLA-B8-positive virus carriers revealed that the BZLF1-specific epitope RAK 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 against EBNA3A-specific epitope FLR and a minority (25%) reacted against EBNA3A-specific epitope QAK.

Naturally processed and HLA‐B8‐presented HPV16 E7 epitope recognized by T cells from patients with cervical cancer

“…Results are expressed as percent HLA-B8 reconstitution. Only the control peptide and E7 [7][8][9][10][11][12][13][14][15] and E7 75-82 were able to reconstitute empty HLA-B8 heavy-chain complexes above 10% (acid-stripped) cell surface expression on C1R-B8 cells. Data are representative of 5 independent experiments; 10,000 events were counted per peptide concentration.…”

“…The HLA-B8-binding (HIV) peptide GGKKKYKL served as a control. Only 2 HPV16 E7 candidate peptides, E7 [7][8][9][10][11][12][13][14][15] and E7 75-82 , were able to reconstitute empty HLA-B8 heavy-chain complexes above 10% of empty HLA-B8 molecule cell surface expression. Irrespective of their affinity to bind to HLA-B8, all peptides listed in Table II were tested for immunogenicity as defined by the capacity to expand HLA-B8-restricted and HPV peptide-specific T cells from PBLs obtained from healthy individuals.…”

“…Irrespective of their affinity to bind to HLA-B8, all peptides listed in Table II were tested for immunogenicity as defined by the capacity to expand HLA-B8-restricted and HPV peptide-specific T cells from PBLs obtained from healthy individuals. Exclusively, the peptide TL-HEYMLDL (E7 [7][8][9][10][11][12][13][14][15] ) has been shown to expand antigen-specific and HLA-B8-restricted T cells in 1/5 PBMC preparations obtained from healthy individuals (Table II) defined by IFN-␥ production, but not by cytotoxicity. This T-cell line recognizes the peptide TLHEYMLDL pulsed onto C1R-B8 cells in a dose-dependent fashion (Fig.…”

“…T cells harvested from tumor-draining lymph nodes obtained from patients 1 and 2 recognized exclusively the peptide E7 [7][8][9][10][11][12][13][14][15] (TLHEYMLDL) in an MHC class I-restricted fashion (Figs. 4b and 5b).…”

“…HLA-B8 has been described to present peptides to T cells directed against human immunodeficiency virus (HIV) [11][12][13] or Epstein-Barr virus (EBV). 14,15 HLA-B8 also appears to play a role in progression to AIDS in HIV-infected individuals 16 and in reduced antibody titers against EBV. 17 Like HIV and EBV, HPV represents a chronic viral infection.…”