Sheng-Fowler Li, Lewis Andrew M, Peden Keith
Laboratory of Retrovirus Research, Division of Viral Products, Center for Biologics Research and Evaluation,Food and Drug Administration, Bethesda, MD 20892, USA.
Biologicals. 2009 Aug;37(4):259-69. doi: 10.1016/j.biologicals.2009.04.002. Epub 2009 May 19.
All viral vaccines contain contaminating residual DNA derived from the production cell substrate. The potential risk of this DNA, particularly when derived from tumorigenic cells, has been debated for over 40 years. While the major risk has been considered to be the oncogenicity of the DNA, another potential risk is that a genome of an infectious virus is present in this DNA. Such a genome might generate an infectious agent that could establish an infection in vaccine recipients. To determine the quantity of a retroviral provirus in cellular DNA that can establish a productive infection in vitro, we developed a transfection/co-culture system capable of recovering infectious virus from 1 pg of cloned HIV DNA and from 2 microg of cellular DNA from HIV-infected cells. We demonstrate that infectivity can be reduced to below detectable levels either by lowering the median size of the DNA to 350 base pairs or by treatment with beta-propiolactone. From the amount of reduction of infectivity, we calculate that clearance values in excess of 10(7) are attainable with respect to the infectivity associated with residual cell-substrate DNA. Thus, the potential risk associated with DNA can be substantially reduced by degradation or by chemical inactivation.
所有病毒疫苗都含有源自生产细胞底物的污染性残留DNA。这种DNA的潜在风险，尤其是当它源自致瘤细胞时，已经争论了40多年。虽然主要风险被认为是DNA的致癌性，但另一个潜在风险是这种DNA中存在传染性病毒的基因组。这样的基因组可能会产生一种传染性病原体，从而在疫苗接种者中引发感染。为了确定细胞DNA中能够在体外建立有效感染的逆转录病毒前病毒的数量，我们开发了一种转染/共培养系统，该系统能够从1 pg克隆的HIV DNA以及从HIV感染细胞的2 μg细胞DNA中回收传染性病毒。我们证明，通过将DNA的中位大小降低到350个碱基对或用β-丙内酯处理，可以将感染性降低到检测不到的水平以下。根据感染性降低的程度，我们计算出相对于与残留细胞底物DNA相关的感染性，清除值超过10^7是可以实现的。因此，与DNA相关的潜在风险可以通过降解或化学灭活大大降低。
