Koedel U, Kohleisen B, Sporer B, Lahrtz F, Ovod V, Fontana A, Erfle V, Pfister H W
Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Germany.
J Immunol. 1999 Aug 1;163(3):1237-45.
Recombinant HIV-1 Nef protein, but not Tat, gp120, and gp160, provoked leukocyte recruitment into the CNS in a rat model. The strong reduction of bioactivity by heat treatment of Nef, and the blocking effect of the mAb 2H12, which recognizes the carboxy-terminal amino acid (aa) residues 171-190 (but not of mAb 3E6, an anti-Nef Ab of the same isotype, which maps the aa sequence 168-175, as well as a mixture of mAbs to CD4) provided evidence for the specificity of the observed Nef effects. Using a modified Boyden chamber technique, Nef exhibited chemotactic activity on mononuclear cells in vitro. Coadministration of the anti-Nef mAb 2H12, as well as treatment of Nef by heat inhibited Nef-induced chemotaxis. Besides soluble Nef, chemotaxis was also induced by a Nef-expressing human astrocytoma cell line, but not by control cells. These data suggest a direct chemotactic activity of soluble Nef. The detection of elevated levels of IL-6, TNF-alpha, and IFN-gamma in rat cerebrospinal fluid 6 h after intracisternal Nef injection hint at the additional involvement of indirect mechanisms in Nef-induced leukocyte migration into rat CNS. These data propose a mechanism by which HIV-1 Nef protein may be essential for AIDS neuropathogenesis, as a mediator of the recruitment of leukocytes that may serve as vehicles of the virus and perpetrators for disease through their production of neurotoxins.
在大鼠模型中，重组HIV-1 Nef蛋白而非Tat、gp120和gp160可促使白细胞募集进入中枢神经系统。通过热处理Nef可使其生物活性大幅降低，以及识别羧基末端氨基酸（aa）残基171 - 190的单克隆抗体2H12（而非同型的抗Nef单克隆抗体3E6，其定位aa序列168 - 175，以及针对CD4的单克隆抗体混合物）的阻断作用，为所观察到的Nef效应的特异性提供了证据。使用改良的Boyden小室技术，Nef在体外对单核细胞表现出趋化活性。抗Nef单克隆抗体2H12的共同给药以及Nef的热处理均抑制了Nef诱导的趋化作用。除了可溶性Nef外，表达Nef的人星形细胞瘤细胞系也可诱导趋化作用，而对照细胞则不能。这些数据表明可溶性Nef具有直接趋化活性。脑池内注射Nef 6小时后，大鼠脑脊液中IL-6、TNF-α和IFN-γ水平升高，这提示间接机制在Nef诱导白细胞迁移至大鼠中枢神经系统中也有额外参与。这些数据提出了一种机制，通过该机制HIV-1 Nef蛋白可能作为白细胞募集的介质，对于艾滋病神经病变至关重要，白细胞可能作为病毒载体，并通过产生神经毒素成为疾病的肇事者。
