Van Parijs L, Ibraghimov A, Abbas A K
Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Immunity. 1996 Mar;4(3):321-8. doi: 10.1016/s1074-7613(00)80440-9.
Using cells from TCR transgenic mice that do or do not express Fas, we show that there are two mechanistically distinct forms of apoptosis in CD4+ T cells. Naive T cells undergo apoptosis if cultured in the absence of antigen or costimulation. This form of programmed cell death (PCD) is not dependent on Fas, and is prevented by CD28-mediated signals, which lead to the secretion of growth factors and the expression of survival genes, such as bcl-xL. Recently activated T cells undergo apoptotic death upon repeated stimulation. This activation-induced cell death (AICD) is mediated by Fas, but is independent of costimulation and is not prevented by IL-2 or bcl-xL. Finally, we show that peripheral tolerance may be induced in vivo independent of Fas-mediated cell death.
利用来自表达或不表达Fas的TCR转基因小鼠的细胞，我们发现CD4 + T细胞中存在两种机制不同的凋亡形式。幼稚T细胞如果在没有抗原或共刺激的情况下培养会发生凋亡。这种程序性细胞死亡（PCD）形式不依赖于Fas，并被CD28介导的信号所阻止，该信号导致生长因子的分泌和存活基因（如bcl-xL）的表达。最近激活的T细胞在反复刺激后会发生凋亡死亡。这种激活诱导的细胞死亡（AICD）由Fas介导，但不依赖于共刺激，并且不受IL-2或bcl-xL的阻止。最后，我们表明外周耐受可能在体内独立于Fas介导的细胞死亡而被诱导。
