HTLV-1 infection promotes excessive T cell activation and transformation into adult T cell leukemia/lymphoma
Benjy J.Y. Tan, Kenji Sugata, Omnia Reda, Misaki Matsuo, Kyosuke Uchiyama, Paola Miyazato, Vincent Hahaut, Makoto Yamagishi, Kaoru Uchimaru, Yutaka Suzuki, Takamasa Ueno, Hitoshi Suzushima, Hiroo Katsuya, Masahito Tokunaga, Yoshikazu Uchiyama, Hideaki Nakamura, Eisaburo Sueoka, Atae Utsunomiya, Masahiro Ono, Yorifumi Satou
Benjy J.Y. Tan, Kenji Sugata, Omnia Reda, Misaki Matsuo, Kyosuke Uchiyama, Paola Miyazato, Vincent Hahaut, Makoto Yamagishi, Kaoru Uchimaru, Yutaka Suzuki, Takamasa Ueno, Hitoshi Suzushima, Hiroo Katsuya, Masahito Tokunaga, Yoshikazu Uchiyama, Hideaki Nakamura, Eisaburo Sueoka, Atae Utsunomiya, Masahiro Ono, Yorifumi Satou
View: Text | PDF
Research Article Infectious disease Virology

HTLV-1 infection promotes excessive T cell activation and transformation into adult T cell leukemia/lymphoma

Abstract

Human T cell leukemia virus type 1 (HTLV-1) mainly infects CD4+ T cells and induces chronic, persistent infection in infected individuals, with some developing adult T cell leukemia/lymphoma (ATL). HTLV-1 alters cellular differentiation, activation, and survival; however, it is unknown whether and how these changes contribute to the malignant transformation of infected cells. In this study, we used single-cell RNA-sequencing and T cell receptor–sequencing to investigate the differentiation and HTLV-1–mediated transformation of T cells. We analyzed 87,742 PBMCs from 12 infected and 3 uninfected individuals. Using multiple independent bioinformatics methods, we demonstrated the seamless transition of naive T cells into activated T cells, whereby HTLV-1–infected cells in an activated state further transformed into ATL cells, which are characterized as clonally expanded, highly activated T cells. Notably, the greater the activation state of ATL cells, the more they acquire Treg signatures. Intriguingly, the expression of HLA class II genes in HTLV-1–infected cells was uniquely induced by the viral protein Tax and further upregulated in ATL cells. Functional assays revealed that HTLV-1–infected cells upregulated HLA class II molecules and acted as tolerogenic antigen-presenting cells to induce anergy of antigen-specific T cells. In conclusion, our study revealed the in vivo mechanisms of HTLV-1–mediated transformation and immune escape at the single-cell level.

Authors

Benjy J.Y. Tan, Kenji Sugata, Omnia Reda, Misaki Matsuo, Kyosuke Uchiyama, Paola Miyazato, Vincent Hahaut, Makoto Yamagishi, Kaoru Uchimaru, Yutaka Suzuki, Takamasa Ueno, Hitoshi Suzushima, Hiroo Katsuya, Masahito Tokunaga, Yoshikazu Uchiyama, Hideaki Nakamura, Eisaburo Sueoka, Atae Utsunomiya, Masahiro Ono, Yorifumi Satou

×

Figure 9

Schematic showing our proposed model of the immunosuppressive properties of ATL cells.

Options: View larger image (or click on image) Download as PowerPoint
Schematic showing our proposed model of the immunosuppressive properties...
(A and B) ATL cells exert their immunosuppressive function by 2 mechanisms. (A) ATL cells acquire the Treg phenotype. ATL cells upregulate coinhibitory molecules (CTLA4, LAG3) to impair the maturation of APCs and reduce costimulatory signals required for complete T cell activation. They also upregulate CD25, leading to an increased consumption of IL-2, which reduces the amount of IL-2 available for effector T cell proliferation and activation. (B) ATL cells act as tolerogenic APCs. They upregulate HLA class II for antigen presentation, but since these ATL cells lack costimulatory signals, the target T cells are not activated, leading to T cell unresponsiveness and anergy.