HTLV-1 Tax-Specific CTL Epitope-Pulsed Dendritic Cell Therapy Reduces Proviral Load in Infected Rats with Immune Tolerance against Tax.

Satomi Ando, Atsuhiko Hasegawa, Yuji Murakami, Na Zeng, Natsuko Takatsuka, Yasuhiro Maeda, Takao Masuda, Youko Suehiro, Mari Kannagi

Journal of immunology (Baltimore, Md. : 1950) 2017 Feb 01

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Adult T cell leukemia/lymphoma (ATL), a CD4+ T cell malignancy with a poor prognosis, is caused by human T cell leukemia virus type 1 (HTLV-1) infection. High proviral load (PVL) is a risk factor for the progression to ATL. We previously reported that some asymptomatic carriers had severely reduced functions of CTLs against HTLV-1 Tax, the major target Ag. Furthermore, the CTL responses tended to be inversely correlated with PVL, suggesting that weak HTLV-1-specific CTL responses may be involved in the elevation of PVL. Our previous animal studies indicated that oral HTLV-1 infection, the major route of infection, caused persistent infection with higher PVL in rats compared with other routes. In this study, we found that Tax-specific CD8+ T cells were present, but not functional, in orally infected rats as observed in some human asymptomatic carriers. Even in the infected rats with immune unresponsiveness against Tax, Tax-specific CTL epitope-pulsed dendritic cell (DC) therapy reduced the PVL and induced Tax-specific CD8+ T cells capable of proliferating and producing IFN-γ. Furthermore, we found that monocyte-derived DCs from most infected individuals still had the capacity to stimulate CMV-specific autologous CTLs in vitro, indicating that DC therapy may be applicable to most infected individuals. These data suggest that peptide-pulsed DC immunotherapy will be useful to induce functional HTLV-1-specific CTLs and decrease PVL in infected individuals with high PVL and impaired HTLV-1-specific CTL responses, thereby reducing the risk of the development of ATL. Copyright © 2017 by The American Association of Immunologists, Inc.

Citation

Satomi Ando, Atsuhiko Hasegawa, Yuji Murakami, Na Zeng, Natsuko Takatsuka, Yasuhiro Maeda, Takao Masuda, Youko Suehiro, Mari Kannagi. HTLV-1 Tax-Specific CTL Epitope-Pulsed Dendritic Cell Therapy Reduces Proviral Load in Infected Rats with Immune Tolerance against Tax. Journal of immunology (Baltimore, Md. : 1950). 2017 Feb 01;198(3):1210-1219