CD40 ligation activates murine macrophages via an IFN-γ-dependent mechanism resulting in tumor cell destruction in vitro
CD40 ligation activates murine macrophages via an IFN-γ-dependent mechanism resulting in tumor cell destruction in vitro
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DOI：
10.4049/jimmunol.174.10.6013
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发表时间：
2005-05-15
影响因子：
4.4
通讯作者：
Rakhmilevich, AL
中科院分区：
文献类型：
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作者：
Buhtoiarov, IN;Lum, H;Rakhmilevich, AL
我们以前已经证明激动型抗CD40单抗在体内诱导T细胞非依赖性的抗肿瘤效应。在这项研究中，我们通过巨噬细胞的体外抗肿瘤作用来研究抗CD40单抗处理巨噬细胞激活的机制。C57BL/6小鼠腹腔注射抗CD40单抗可激活巨噬细胞，在体外可抑制B16黑色素瘤细胞的增殖，这种作用可被脂多糖显著增强，并对多种小鼠和人肿瘤细胞系有明显的抑制作用。抗CD40单抗在体外也能激活巨噬细胞，从而在有内毒素存在的情况下发挥细胞抑制作用。CD40结扎激活的巨噬细胞的抗肿瘤作用与肿瘤细胞的凋亡和杀伤有关。用抗CD40单抗激活巨噬细胞需要内源性的干扰素-γ，因为在抗-干扰素-γ单抗存在的情况下，抗-CD40单抗对巨噬细胞的启动作用被取消了，在干扰素-γ基因敲除的小鼠中也是如此。抗CD40单抗仍能激活C57BL/6小鼠和SCID/Beige小鼠的巨噬细胞，以介导细胞抑制活性。这些结果反对NK和T细胞是激活巨噬细胞的外源性干扰素-γ的唯一来源，并提示抗CD40单抗激活的巨噬细胞可以产生干扰素-γ。我们通过检测体内或体外用抗CD40单抗激活的巨噬细胞胞浆内的干扰素-γ证实了这一假设。巨噬细胞产生的干扰素依赖于IL-12。综上所述，结果表明，抗CD40单抗可直接激活小鼠巨噬细胞分泌干扰素-γ，并介导肿瘤细胞的破坏。
We have shown previously that agonistic anti-CD40 mAb induced T cell-independent antitumor effects in vivo. In this study, we investigated mechanisms of macrophage activation with anti-CD40 mAb treatment, assessed by the antitumor action of macrophages in vitro. Intraperitoneal injection of anti-CD40 mAb into C57BL/6 mice resulted in activation of peritoneal macrophages capable of suppressing B16 melanoma cell proliferation in vitro, an effect that was greatly enhanced by LPS and observed against several murine and human tumor cell lines. Anti-CD40 mAb also primed macrophages in vitro to mediate cytostatic effects in the presence of LPS. The tumoristatic effect of CD40 ligation-activated macrophages was associated with apoptosis and killing of tumor cells. Activation of macrophages by anti-CD40 mAb required endogenous IFN-gamma because priming of macrophages by anti-CD40 mAb was abrogated in the presence of anti-IFN-gamma mAb, as well as in IFN-gamma-knockout mice. Macrophages obtained either from C57BL/6 mice depleted of T and NK cells by Ab treatment, or from scid/beige mice, were still activated by anti-CD40 mAb to mediate cytostatic activity. These results argued against the role of NK and T cells as the sole source of exogenous IFN-gamma for macrophage activation and suggested that anti-CD40 mAb-activated macrophages could produce IFN-gamma. We confirmed this hypothesis by detecting intracytoplasmic IFN-gamma in macrophages activated with anti-CD40 mAb in vivo or in vitro. IFN-gamma production by macrophages was dependent on IL-12. Taken together, the results show that murine macrophages are activated directly by anti-CD40 mAb to secrete IFN-gamma and mediate tumor cell destruction.