By pulling receptors away from their surface membrane during signaling, t cells can prevent themselves from being lethally overstimulated by too much antigen.
在沟通过程中，T细胞会将受体抽离细胞膜表面，以避免因受到过多抗原的刺激而死于非命。
2
They found it was a simple matter of Numbers: by wearing many hats, or antigenreceptors, regulatory t cells can keep their eyes on a lot of different non-regulatory cells.
The first signal is the binding of antigen with TCR on T cells. The second signal is the binding of co-stimulate on the APC with their receptors presenting on T and B lymphocytes.