Luo Y, Yamada H, Evanoff D P, Chen X
Department of Urology, University of Iowa, Iowa City, IA 52242, USA.
Clin Exp Immunol. 2006 Oct;146(1):181-8. doi: 10.1111/j.1365-2249.2006.03191.x.
Previously, we have demonstrated that macrophages exhibited cytotoxicity toward mouse bladder cancer MBT-2 cells upon bacille Calmette-Guérin (BCG) stimulation. In this study, we have investigated the role of Th1-stimulating cytokines in BCG-induced macrophage cytotoxicity. Thioglycollate-elicited peritoneal exudate cells (PECs) were used as a conventional source for macrophages and the induction of PEC effector functions (cytolytic activity and cytokine production) by BCG was evaluated in vitro. The BCG-activated PECs showed potent cytotoxicity and killed MBT-2 cells in a dose-dependent manner. Depletion of T cells, natural killer (NK) cells, or both, in PEC preparations exhibited a marginal or small reduction of MBT-2 cell killing, suggesting that macrophages played a primary role in PEC cytotoxicity. Transwell assays indicated that the maximal PEC cytotoxicity required both direct cell-cell contact and soluble factors such as interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha. Neutralizing endogenous cytokines interleukin (IL)-12, IL-18, IFN-gamma or TNF-alpha reduced PEC cytotoxicity by 38%, 22%, 15% and 94%, respectively. Supplementation of BCG with recombinant (r)IL-2, rIL-12 or rIL-18 increased PEC cytotoxicity by approximately twofold. Compared with control BCG for PEC stimulation, rBCGs expressing IL-2 or IL-18 showed enhanced MBT-2 cell killing by PECs. Increased cytokine production (IFN-gamma, TNF-alpha and IL-6) was also observed in rBCG-stimulated PEC cultures. Taken together, these results suggest that Th1-stimulating cytokines play an important role in BCG-induced macrophage cytotoxicity and that combination of BCG with selected Th1-stimulating cytokines, either supplemented or expressed by BCG, may enhance the effect of BCG in the treatment of bladder cancer patients.
此前，我们已经证明，巨噬细胞在卡介苗（BCG）刺激下对小鼠膀胱癌MBT - 2细胞表现出细胞毒性。在本研究中，我们调查了Th1刺激细胞因子在BCG诱导的巨噬细胞细胞毒性中的作用。用巯基乙酸盐诱导的腹腔渗出细胞（PEC）作为巨噬细胞的传统来源，并在体外评估BCG对PEC效应功能（细胞溶解活性和细胞因子产生）的诱导作用。BCG激活的PEC表现出强大的细胞毒性，并以剂量依赖的方式杀死MBT - 2细胞。在PEC制剂中耗尽T细胞、自然杀伤（NK）细胞或两者，对MBT - 2细胞杀伤作用仅呈现轻微或小幅度降低，这表明巨噬细胞在PEC细胞毒性中起主要作用。Transwell实验表明，最大PEC细胞毒性需要直接的细胞间接触和可溶性因子，如干扰素（IFN）-γ和肿瘤坏死因子（TNF）-α。中和内源性细胞因子白细胞介素（IL）-12、IL - 18、IFN -γ或TNF -α分别使PEC细胞毒性降低38%、22%、15%和94%。用重组（r）IL - 2、rIL - 12或rIL - 18补充BCG可使PEC细胞毒性增加约两倍。与用于刺激PEC的对照BCG相比，表达IL - 2或IL - 18的重组BCG（rBCG）显示PEC对MBT - 2细胞的杀伤作用增强。在rBCG刺激的PEC培养物中也观察到细胞因子产生增加（IFN -γ、TNF -α和IL - 6）。综上所述，这些结果表明Th1刺激细胞因子在BCG诱导的巨噬细胞细胞毒性中起重要作用，并且BCG与选定的Th1刺激细胞因子联合使用，无论是通过补充还是由BCG表达，都可能增强BCG在治疗膀胱癌患者中的效果。
