Schall R P, Sekar J, Tandon P M, Susskind B M
Department of Medical Microbiology and Immunology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
Immunopharmacology. 1991 Mar-Apr;21(2):129-43. doi: 10.1016/0162-3109(91)90016-r.
DL-alpha-Difluoromethylornithine (DFMO) is a specific inhibitor of the rate-limiting enzyme in polyamine biosynthesis, ornithine decarboxylase (ODC). DFMO (1 mM) added to C57BL/6 anti-DBA/2 murine mixed lymphocyte cultures (MLC) inhibited cytolytic T lymphocyte (CTL) activity on days 3 and 5 by 88% and 96%. Putrescine (PUT; 1 mM) and spermidine (SPD; 0.01 mM) reversed DFMO inhibition, indicating that DFMO inhibition was caused by ODC antagonism. T helper (Th) cell and accessory cell functions were not affected since DFMO did not inhibit MLC proliferation or lymphokine production. Furthermore, exogenous IL-1, IL-2, IL-4, interferon-gamma, or a rat Con A supernatant failed to abrogate DFMO inhibition. Inhibition was reversible within 48 h of removing cells from DFMO; moreover, subsequent development of DFMO-blocked CTL did not require CD4+ cells. Clonal expansion of CTL treated with 1 mM DFMO for three days in MLC, determined by subsequent analysis in limiting dilution microcultures, was only approx. 1 cell division less than control. These results indicate DFMO inhibition is exerted directly on the CTL, and that the process of differentiation was more affected by a reduction in polyamine biosynthesis than proliferation. This may be a useful model to the study stages and events of CTL development, and the roles played by polyamines in supporting these processes.
DL-α-二氟甲基鸟氨酸（DFMO）是多胺生物合成限速酶鸟氨酸脱羧酶（ODC）的特异性抑制剂。向C57BL/6抗DBA/2小鼠混合淋巴细胞培养物（MLC）中添加DFMO（1 mM），在第3天和第5天可使细胞毒性T淋巴细胞（CTL）活性分别降低88%和96%。腐胺（PUT；1 mM）和亚精胺（SPD；0.01 mM）可逆转DFMO的抑制作用，表明DFMO的抑制作用是由ODC拮抗引起的。由于DFMO不抑制MLC增殖或淋巴因子产生，因此T辅助（Th）细胞和辅助细胞功能未受影响。此外，外源性白细胞介素-1、白细胞介素-2、白细胞介素-4、干扰素-γ或大鼠刀豆蛋白A上清液均不能消除DFMO的抑制作用。在从DFMO中去除细胞后的48小时内，抑制作用是可逆的；此外，DFMO阻断的CTL的后续发育不需要CD4+细胞。通过有限稀释微培养中的后续分析确定，在MLC中用1 mM DFMO处理三天的CTL的克隆扩增仅比对照少约1个细胞分裂。这些结果表明，DFMO的抑制作用直接作用于CTL，并且多胺生物合成的减少对分化过程的影响大于对增殖的影响。这可能是研究CTL发育阶段和事件以及多胺在支持这些过程中所起作用的有用模型。
