Carreer R, Groux H, Ameisen J C, Capron A
Centre d'Immunologie et de Biologie Parasitaire, Institut Pasteur de Lille, France.
AIDS Res Hum Retroviruses. 1994 May;10(5):523-7. doi: 10.1089/aid.1994.10.523.
The role of the human immunodeficiency virus (HIV-1) Nef protein in T cell activation pathways was investigated using a Jurkat CD4+ cell line stably transfected with a Nef expression vector. Secretion of IL-2 and TNF-alpha, surface expression of IL-2R, and DNA-binding activity of NF-kappa B and AP-1 (Fos/Jun) complex in response to phorbol myristate acetate, TNF-alpha, or immobilized antibodies to CD3 were monitored. These parameters were not modified by Nef expression in Jurkat cells, whereas stimulation with the same stimuli resulted in partial inhibition of LTR activation in Nef+ Jurkat cells. This inhibition was not mediated through Nef phosphorylation on Thr-15 or GTP-binding activity because mutations in critical sites did not alter this inhibition. Analysis of truncated LTRs confirmed that inhibition of LTR activation was not mediated through NF-kappa B-binding activity but through the region containing the negative responding elements (NREs). These results suggest that Nef downmodulates LTR activation without significantly inhibiting the capacity of T cells to respond to immunological activations.
利用稳定转染了Nef表达载体的Jurkat CD4 +细胞系，研究了人类免疫缺陷病毒（HIV-1）Nef蛋白在T细胞激活途径中的作用。监测了佛波醇肉豆蔻酸酯乙酸酯、TNF-α或固定化抗CD3抗体刺激后，IL-2和TNF-α的分泌、IL-2R的表面表达以及NF-κB和AP-1（Fos/Jun）复合物的DNA结合活性。这些参数在Jurkat细胞中不受Nef表达的影响，而相同刺激在Nef + Jurkat细胞中导致LTR激活部分受抑制。这种抑制不是通过Nef在Thr-15上的磷酸化或GTP结合活性介导的，因为关键位点的突变并未改变这种抑制作用。对截短LTR的分析证实，LTR激活的抑制不是通过NF-κB结合活性介导的，而是通过包含负反应元件（NRE）的区域介导的。这些结果表明，Nef下调LTR激活，而不会显著抑制T细胞对免疫激活的反应能力。
