Ahmad A, Yao X A, Tanner J E, Cohen E, Menezes J
Laboratory of Immunovirology, University of Montreal, Quebec, Canada.
J Acquir Immune Defic Syndr (1988). 1994 Aug;7(8):789-98.
The env gene of the human immunodeficiency virus-type 1 (HIV-1) was transfected in CEM-nkr, a human lymphoid cell line of T lineage that is resistant to the activity of natural killer cells, and for the first time, transfected T cell clones were established that stably express gp160 intracellularly and gp120 on the surface as demonstrated by radioimmunoprecipitation as well as by indirect membrane immunofluorescence. The regulatory protein vpu was not detected by radioimmunoprecipitation in these clones. The surface expression of gp120 without vpu in these clones provides direct evidence that gp160 is processed and cleaved (without vpu) in CD4+ cells. The CD4 antigens of these cells coprecipitated gp160; interestingly, no reduction of the surface CD4 expression (detectable by flow cytometric analysis of membrane immunofluorescence with OKT4) in the transfected cells was observed. However, decreased reactivity of the transfected clones with OKT4A was observed. The gp120-expressing cells did not form syncytia on coculture with other CD4+ human cell lines. These observations suggest the binding of gp120 to the surface CD4 antigen of the transfected cells. The transfected cells retained their resistance to the activity of the natural killer cells but showed a significant (p < 0.05) lysis when they were preincubated with AIDS patients' serum containing anti-gp120/41 antibodies. Thus, the expressed gp120/41 in these cells made them susceptible to killing by an antibody-dependent cellular cytotoxicity (ADCC) mechanism. To our knowledge, these are the first reported CD4+ T cell lines that stably express HIV envelope proteins. These cell lines would be useful as targets in exploring gp120/41-specific immune responses, especially in conducting gp120/41-specific ADCC studies in HIV-infected or gp120/41 (gp160)-vaccinated individuals.
将人类免疫缺陷病毒1型（HIV-1）的env基因转染到CEM-nkr中，CEM-nkr是一种T淋巴细胞系的人类淋巴细胞系，对自然杀伤细胞的活性具有抗性。首次建立了转染的T细胞克隆，通过放射免疫沉淀以及间接膜免疫荧光证明，这些克隆在细胞内稳定表达gp160，在表面稳定表达gp120。在这些克隆中，通过放射免疫沉淀未检测到调节蛋白vpu。这些克隆中没有vpu时gp120的表面表达提供了直接证据，表明gp160在CD4+细胞中被加工和切割（无vpu）。这些细胞的CD4抗原与gp160共沉淀；有趣的是，在转染细胞中未观察到表面CD4表达的降低（通过用OKT4进行膜免疫荧光的流式细胞术分析可检测到）。然而，观察到转染克隆与OKT4A的反应性降低。表达gp120的细胞与其他CD4+人类细胞系共培养时未形成多核巨细胞。这些观察结果表明gp120与转染细胞的表面CD4抗原结合。转染细胞保留了对自然杀伤细胞活性的抗性，但当它们与含有抗gp120/41抗体的艾滋病患者血清预孵育时，显示出显著的（p<0.05）裂解。因此，这些细胞中表达的gp120/41使它们易受抗体依赖性细胞毒性（ADCC）机制的杀伤。据我们所知，这些是首次报道的稳定表达HIV包膜蛋白的CD4+T细胞系。这些细胞系作为探索gp120/41特异性免疫反应的靶标将是有用的，特别是在HIV感染或接种gp120/41（gp160）疫苗的个体中进行gp120/41特异性ADCC研究。
