Harakeh S, Jariwalla R J
Virology and Immunodeficiency Research Program, Linus Pauling Institute of Science and Medicine, Palo Alto, California 94306, USA.
Nutrition. 1995 Sep-Oct;11(5 Suppl):684-7.
We have recently shown that ascorbic acid (AA) suppresses the production of HIV in a latently infected T-lymphocytic cell line (ACH-2) following stimulation with the tumor promoter, PMA. To evaluate the effect of ascorbic acid on virus activation following treatment with inflammatory cytokine, we tested tumor necrosis factor alpha (TNF-alpha) whose levels are elevated in patients with HIV/AIDS. ACH-2 cultures, pretreated with various nontoxic concentrations of ascorbate or AZT were stimulated for 2 h with TNF-alpha, and incubated further with fresh supplements of ascorbate or AZT. At 24 to 48 h post-treatment, the RT activity released into culture supernatant was determined. Results showed that TNF-alpha alone caused approximately 13- to 16-fold stimulation in the level of extracellular RT. Pretreatment with ascorbic acid at 200 micrograms/ml caused a little more than about 2- to 4-fold reduction in extracellular RT levels. Most remarkably, exposure to 300 micrograms/ml ascorbate resulted in approximately 5- to 10-fold lowering of the extra-cellular RT titer. In contrast, no significant suppression in extracellular RT levels was seen with concentrations of AZT in the range of 1-5 micrograms/ml.
我们最近发现，在经肿瘤启动子佛波酯（PMA）刺激后，抗坏血酸（AA）可抑制潜伏感染的T淋巴细胞系（ACH-2）中HIV的产生。为评估抗坏血酸对炎性细胞因子处理后病毒激活的影响，我们检测了肿瘤坏死因子α（TNF-α），其在HIV/AIDS患者体内水平升高。用不同无毒浓度的抗坏血酸盐或齐多夫定（AZT）预处理ACH-2培养物，再用TNF-α刺激2小时，然后用新鲜的抗坏血酸盐或AZT补充物进一步孵育。在处理后24至48小时，测定释放到培养上清液中的逆转录酶（RT）活性。结果显示，单独使用TNF-α可使细胞外RT水平刺激约13至16倍。用200微克/毫升的抗坏血酸预处理可使细胞外RT水平降低约2至4倍多一点。最显著的是，暴露于300微克/毫升的抗坏血酸盐会使细胞外RT滴度降低约5至10倍。相比之下，1至5微克/毫升范围内的AZT浓度对细胞外RT水平无明显抑制作用。
