[HTML][HTML] CD155-transducing signaling through TIGIT plays an important role in transmission of tolerant state and suppression capacity

N Negishi, T Sato, Y Yamashita-Kanemaru… - …, 2018 - journals.aai.org
N Negishi, T Sato, Y Yamashita-Kanemaru, K Shibuya, K Uchida, Y Kametani, H Yagita…
Immunohorizons, 2018journals.aai.org
The precise mechanism of how the regulatory T cell population elicits and maintains tolerant
state in activated T cells is poorly understood. To address this issue, we established an in
vitro coculture system using mouse T cells and showed that tolerant state is serially passed
from preinduced-tolerant T cells into new TCR-stimulated T cells across generations in a
dendritic cell–independent manner. In this successive induction process of tolerant state,
TIGIT was found to play an important role: TIGIT expression on induced-tolerant T cells was …
Abstract
The precise mechanism of how the regulatory T cell population elicits and maintains tolerant state in activated T cells is poorly understood. To address this issue, we established an in vitro coculture system using mouse T cells and showed that tolerant state is serially passed from preinduced-tolerant T cells into new TCR-stimulated T cells across generations in a dendritic cell–independent manner. In this successive induction process of tolerant state, TIGIT was found to play an important role: TIGIT expression on induced-tolerant T cells was promoted in stimulated T cells cocultured with the tolerant cells. In addition, these stimulated T cells in the coculture also expressed high B lymphocyte-induced maturation protein 1 accompanied by IL-2 suppression. Because CD155, a partner of TIGIT, is known to transduce signaling inside by trans-interaction with its ligands, these phenotypical changes in TCR-stimulated naive T cells were reproduced when naive T cells were double cross-linked by CD3 and CD155. These results indicate that TIGIT enhanced on tolerant T cells may function as a ligand of its paired receptor CD155 to transduce signaling into its expressing naive T cells to accelerate new TIGIT expressions as well as IL-2 suppression via B lymphocyte-induced maturation protein 1 enhancement. In consideration of these results, we propose a novel process in which tolerant state in T cell population is maintained by successive generation of new tolerant T cells from naive T cells as one of the regulating mechanisms in immune responses.
journals.aai.org