Chirmule N, Goonewardena H, Pahwa S, Pasieka R, Kalyanaraman V S, Pahwa S
Department of Pediatrics, North Shore University Hospital, Cornell University Medical College, Manhasset, New York 11030, USA.
J Biol Chem. 1995 Aug 18;270(33):19364-9. doi: 10.1074/jbc.270.33.19364.
Activation of CD4 positive T cells is a primary requirement for human immunodeficiency virus (HIV) entry, efficient HIV replication, and progression to AIDS, Utilizing CD4 positive T cell lines and purified T cells from normal individuals, we have demonstrated that native envelope glycoproteins of HIV, gp 160, can induce activation of transcription factor, activated protein-1 (AP-1). The stimulatory effects of gp160 are mediated through the CD4 molecule, since treatment of gp160 with soluble CD4-IgG abrogates its activity, and CD4 negative T cell lines fail to be stimulated with gp160. Immunoprecipitation of the gp 160-induced nuclear extracts with polyclonal antibodies to Fos and Jun proteins indicates that AP-1 complex is comprised of members of these family of proteins. The gp160-induced AP-1 complex is dependent upon protein tyrosine phosphorylation and is protein synthesis-independent. This stimulation can also be abolished by inhibitors of protein kinase C, but it is unaffected by calcium channel blocker or cyclosporine A. This gp160 treatment adversely affects the functional capabilities of T cells: pre-treatment of CD4+ T cells with gp160 for 4 h at 37 degrees C inhibited anti-CD3-induced interleukin-2 secretion. Effects similar to gp160 were seen with anti-CD4 mAb. The aberrant activation of AP-1 by gp160 in CD4 positive T cells could result in up-regulation of cytokines containing AP-1 sites, e.g. interleukin-3 and granulocyte macrophage colony-stimulating factor, and concurrently lead to T cell unresponsiveness by inhibiting interleukin-2 secretion.
CD4 阳性 T 细胞的激活是人类免疫缺陷病毒（HIV）进入、高效 HIV 复制以及发展为艾滋病的主要条件。利用 CD4 阳性 T 细胞系和来自正常个体的纯化 T 细胞，我们已证明 HIV 的天然包膜糖蛋白 gp160 可诱导转录因子活化蛋白 -1（AP-1）的激活。gp160 的刺激作用是通过 CD4 分子介导的，因为用可溶性 CD4-IgG 处理 gp160 会消除其活性，并且 CD4 阴性 T 细胞系不能被 gp160 刺激。用针对 Fos 和 Jun 蛋白的多克隆抗体对 gp160 诱导的核提取物进行免疫沉淀表明，AP-1 复合物由这些蛋白家族的成员组成。gp160 诱导的 AP-1 复合物依赖于蛋白酪氨酸磷酸化且与蛋白质合成无关。这种刺激也可被蛋白激酶 C 的抑制剂消除，但不受钙通道阻滞剂或环孢素 A 的影响。这种 gp160 处理对 T 细胞的功能能力有不利影响：在 37℃用 gp160 预处理 CD4 + T 细胞 4 小时可抑制抗 CD3 诱导的白细胞介素 -2 分泌。用抗 CD4 单克隆抗体可观察到与 gp160 类似的效果。gp160 在 CD4 阳性 T 细胞中异常激活 AP-1 可能导致含有 AP-1 位点的细胞因子上调，例如白细胞介素 -3 和粒细胞巨噬细胞集落刺激因子，并同时通过抑制白细胞介素 -2 分泌导致 T 细胞无反应性。
