Chakrabarti B K, Maitra R K, Ma X Z, Kestler H W
Department of Molecular Biology, Cleveland Clinic Foundation, OH 44195, USA.
Proc Natl Acad Sci U S A. 1996 Sep 3;93(18):9810-5. doi: 10.1073/pnas.93.18.9810.
The recent discovery of long term AIDS nonprogressors who harbor nef-attenuated HIV suggests that a naturally occurring live vaccine for AIDS may already exist. Animal models have shown that a live vaccine for AIDS, attenuated in nef, is the best candidate vaccine. There are considerable risks, real and perceived, with the use of live HIV vaccines. We have introduced a conditional lethal genetic element into HIV-1 and simian immunodeficiency virus (SIV) molecular clones deleted in nef. The antiviral strategy we employed targets both virus replication and the survival of the infected cell. The suicide gene, herpes simplex virus thymidine kinase (tk), was expressed and maintained in HIV over long periods of time. Herpes simplex virus tk confers sensitivity to the antiviral activity of acyclic nucleosides such as ganciclovir (GCV). HIV-tk and SIV-tk replication were sensitive to GCV at subtoxic concentrations, and virus-infected cells were eliminated from tumor cell lines as well as primary cell cultures. We found the HIV-tk virus to be remarkably stable even after being cultured in media containing a low concentration of GCV and then challenged with the higher dose and that while GCV resistant escape mutants did arise, a significant fraction of the virus remained sensitive to GCV.
最近发现携带nef弱化型HIV的长期艾滋病非进展者，这表明一种天然存在的艾滋病活疫苗可能已然存在。动物模型显示，一种在nef基因上减毒的艾滋病活疫苗是最佳候选疫苗。使用活HIV疫苗存在诸多实际的和认知上的风险。我们已将一种条件致死性遗传元件引入在nef基因上缺失的HIV-1和猴免疫缺陷病毒（SIV）分子克隆中。我们采用的抗病毒策略既针对病毒复制，也针对被感染细胞的存活。自杀基因单纯疱疹病毒胸苷激酶（tk）在HIV中长时间表达并维持。单纯疱疹病毒tk赋予细胞对无环核苷如更昔洛韦（GCV）抗病毒活性的敏感性。HIV-tk和SIV-tk复制对亚毒性浓度的GCV敏感，并且病毒感染细胞从肿瘤细胞系以及原代细胞培养物中被清除。我们发现HIV-tk病毒即使在含有低浓度GCV的培养基中培养后再用高剂量进行攻击时仍非常稳定，而且虽然确实出现了对GCV耐药的逃逸突变体，但仍有相当一部分病毒对GCV敏感。
