TY - JOUR
T1 - In vitro peptide immunization of target tax protein human T-cell leukemia virus type 1-specific CD4+ helper T lymphocytes
AU - Kobayashi, Hiroya
AU - Ngato, Toshihiro
AU - Sato, Keisuke
AU - Aoki, Naoko
AU - Kimura, Shoji
AU - Tanaka, Yuetsu
AU - Aizawa, Hitoshi
AU - Tateno, Masatoshi
AU - Celis, Esteban
PY - 2006/6/15
Y1 - 2006/6/15
N2 - Purpose: Adult T-cell leukemia/lymphoma induced by human T-cell leukemia virus type 1 (HTLV-1) is usually a fatal lymphoproliferative malignant disease. HTLV-1 Tax protein plays a critical role in HTLV-1-associated leukemogenesis and is an attractive target for vaccine development. Although HTLV-1 Tax is the most dominant antigen for HTLV-1-specific CD8+ CTLs in HTLV-1-infected individuals, few epitopes recognized by CD4+ helper T lymphocytes in HTLV-1 Tax protein have been described. The aim of the present study was to study T-helper-cell responses to HTLV-1 Tax and to identify naturally processed MHC class II - restricted epitopes that could be used for vaccine development. Experimental Design: An MHC class II binding peptide algorithm was used to predict potential T-helper cell epitope peptides from HTLV-1 Tax. We assessed the ability of the corresponding peptides to elicit helper T-cell responses by in vitro vaccination of purified CD4+ T lymphocytes. Results: Peptides Tax191-205 and Tax305-319 were effective in inducing T-helper-cell responses. Although Tax 191-205 was restricted by the HLA-DR1 and DR9 alleles, responses to TaX305-319 were restricted by either DR15 or DQ9. Both these epitopes were found to be naturally processed by HTLV-1+ T-cell lymphoma cells and by autologous antigen-presenting cells that were pulsed with HTLV-1 Tax+ tumor lysates. Notably, the two newly identified helper T-cell epitopes are found to lie proximal to known CTL epitopes, which will facilitate the development of prophylactic peptide - based vaccine capable of inducing simultaneous CTL and T-helper responses. Conclusion: Our data suggest that HTLV-1 Tax protein could serve as tumor-associated antigen for CD4+ helper T cells and that the present epitopes might be used for T-cell-based immunotherapy against tumors expressing HTLV-1.
AB - Purpose: Adult T-cell leukemia/lymphoma induced by human T-cell leukemia virus type 1 (HTLV-1) is usually a fatal lymphoproliferative malignant disease. HTLV-1 Tax protein plays a critical role in HTLV-1-associated leukemogenesis and is an attractive target for vaccine development. Although HTLV-1 Tax is the most dominant antigen for HTLV-1-specific CD8+ CTLs in HTLV-1-infected individuals, few epitopes recognized by CD4+ helper T lymphocytes in HTLV-1 Tax protein have been described. The aim of the present study was to study T-helper-cell responses to HTLV-1 Tax and to identify naturally processed MHC class II - restricted epitopes that could be used for vaccine development. Experimental Design: An MHC class II binding peptide algorithm was used to predict potential T-helper cell epitope peptides from HTLV-1 Tax. We assessed the ability of the corresponding peptides to elicit helper T-cell responses by in vitro vaccination of purified CD4+ T lymphocytes. Results: Peptides Tax191-205 and Tax305-319 were effective in inducing T-helper-cell responses. Although Tax 191-205 was restricted by the HLA-DR1 and DR9 alleles, responses to TaX305-319 were restricted by either DR15 or DQ9. Both these epitopes were found to be naturally processed by HTLV-1+ T-cell lymphoma cells and by autologous antigen-presenting cells that were pulsed with HTLV-1 Tax+ tumor lysates. Notably, the two newly identified helper T-cell epitopes are found to lie proximal to known CTL epitopes, which will facilitate the development of prophylactic peptide - based vaccine capable of inducing simultaneous CTL and T-helper responses. Conclusion: Our data suggest that HTLV-1 Tax protein could serve as tumor-associated antigen for CD4+ helper T cells and that the present epitopes might be used for T-cell-based immunotherapy against tumors expressing HTLV-1.
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U2 - 10.1158/1078-0432.CCR-06-0384
DO - 10.1158/1078-0432.CCR-06-0384
M3 - Article
C2 - 16778109
AN - SCOPUS:33745697739
SN - 1078-0432
VL - 12
SP - 3814
EP - 3822
JO - Clinical Cancer Research
JF - Clinical Cancer Research
IS - 12
ER -