複選題
23.最近新上市一種抗氣喘藥物，您發現氣喘病人治療幾個月後，不僅相關臨床症狀消失，檢測血液中抗原特異 性IgE抗體效價也降低，而且也偵測不到抗原特異性CD4⁺ T細胞分泌的IL-4、IL-5及IL-13，這種抗氣喘藥物可 能具有調節免疫反應的功能，下列那種細胞最不可能與這種治療效果有關？
(A)第一型輔助性T細胞（T_H1）
(B)TR1細胞
(C)第十七型輔助性T細胞（T_H17）
(D)CD4⁺ CD25⁺ T細胞

Natural  T-regulatory  (nT reg )  cells develop in the thymus and are CD4-positive cells that constitutively express CD25 and high levels of the L-selectin receptor CD62L and of CTLA-4. Induced T reg  (iT reg ) cells arise in the periphery from naive CD4 T cells and also express CD25 and CTLA-4.

A hallmark of both natural and induced T reg  cells is expression of the transcription factor FoxP3, which, among other actions, interferes with the interaction between AP-1 and NFAT at the IL-2 gene promoter, preventing transcriptional activation of the gene and production of IL-2.

CD4  T  cells  that  lack  FoxP3  expression  but  produce  immunosuppressive cytokines characteristic of T reg  cells have also been described. One such population, referred to as T R 1 cells, has been defined largely by their production of IL-10, but absence of expression of FoxP3.