Richard M, Hoskin D W
Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
Int J Immunopharmacol. 1998 Apr-May;20(4-5):241-52. doi: 10.1016/s0192-0561(98)00029-0.
Pentoxifylline (PTX), rapamycin (RAP), and leflunomide are potent immunomodulatory drugs with differing modes of action. In order to develop new drug combinations for immunotherapy, we tested the effects of PTX in combination with RAP or A77 1726 (the active metabolite of leflunomide) on in vitro T cell activation in a mouse model system. T lymphocytes in spleen cell preparations were stimulated with anti-CD3 monoclonal antibody alone, or in the presence of PTX (25-200 microg/ml), RAP (0.5-5.0 ng/ml), A77 1726 (2.5-10.0 microM), PTX/RAP (25-200 microg/ml and 0.5-5.0 ng/ml, respectively), or PTX/A77 1726 (25-200 microg/ml and 2.5-10.0 microM, respectively). Anti-CD3-induced T cell proliferation was inhibited in a dose-dependent fashion by the individual drugs. An additive inhibitory effect was observed in cultures treated with PTX/RAP or PTX/A77 1726. The effects of PTX, RAP, A77 1726, PTX/RAP, or PTX/A77 1726 (at concentrations approximating the IC50 of individual drugs for inhibition of lymphoproliferation) on anti-CD3-activated killer (AK) cell induction, CD25 expression, and interleukin (IL)-2 synthesis in anti-CD3-activated spleen cell cultures were also determined. Alone, each drug was able to suppress AK cell induction to varying degrees. PTX plus RAP exhibited strong synergism, while the combination of PTX and A77 1726 had an additive inhibitory effect on AK cell induction. CD25 expression was only weakly inhibited by A77 1726, but the percentage of CD25-expressing cells was greatly reduced in cultures treated with PTX or RAP. The combination of PTX and RAP had an additive inhibitory effect on CD25 expression while PTX and A77 1726 together had an effect equivalent to PTX alone. IL-2 synthesis was inhibited by PTX but was unaffected by RAP or A77 1726. Treatment with PTX plus RAP led to a further reduction in IL-2 production but co-treatment with PTX and A77 1726 approximated the inhibitory effect of PTX alone. We conclude that the combination of PTX and RAP is noteworthy for its potent immunomodulatory activity and may be of use in clinical situations where it is desirable to prevent T cell activation.
己酮可可碱（PTX）、雷帕霉素（RAP）和来氟米特是具有不同作用方式的强效免疫调节药物。为了开发用于免疫治疗的新药物组合，我们在小鼠模型系统中测试了PTX与RAP或A77 1726（来氟米特的活性代谢物）联合使用对体外T细胞活化的影响。脾细胞制剂中的T淋巴细胞单独用抗CD3单克隆抗体刺激，或在PTX（25 - 200微克/毫升）、RAP（0.5 - 5.0纳克/毫升）、A77 1726（2.5 - 10.0微摩尔）、PTX/RAP（分别为25 - 200微克/毫升和0.5 - 5.0纳克/毫升）或PTX/A77 1726（分别为25 - 200微克/毫升和2.5 - 10.0微摩尔）存在的情况下刺激。抗CD3诱导的T细胞增殖被各药物以剂量依赖方式抑制。在用PTX/RAP或PTX/A77 1726处理的培养物中观察到相加抑制作用。还测定了PTX、RAP、A77 1726、PTX/RAP或PTX/A77 1726（浓度接近各药物抑制淋巴细胞增殖的IC50）对抗CD3激活的杀伤（AK）细胞诱导、CD25表达以及抗CD3激活的脾细胞培养物中白细胞介素（IL）-2合成的影响。单独使用时，每种药物都能不同程度地抑制AK细胞诱导。PTX加RAP表现出强烈的协同作用，而PTX和A77 1726的组合对AK细胞诱导具有相加抑制作用。A77 1726仅微弱抑制CD25表达，但在用PTX或RAP处理的培养物中，表达CD25的细胞百分比大大降低。PTX和RAP的组合对CD25表达具有相加抑制作用，而PTX和A77 1726共同作用的效果与单独使用PTX相当。IL-2合成被PTX抑制，但不受RAP或A77 1726影响。PTX加RAP处理导致IL-2产生进一步降低，但PTX和A77 1726联合处理接近单独使用PTX的抑制效果。我们得出结论，PTX和RAP的组合因其强大的免疫调节活性而值得关注，可能在需要预防T细胞活化的临床情况下有用。
