BLOCKING OF HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION DEPENDS ON CELL-DENSITY AND VIRAL STOCK AGE
BLOCKING OF HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION DEPENDS ON CELL-DENSITY AND VIRAL STOCK AGE
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DOI：
10.1128/jvi.65.6.3293-3300.1991
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发表时间：
1991-06-01
影响因子：
5.4
通讯作者：
NARA, PL
中科院分区：
文献类型：
--
作者：
LAYNE, SP;MERGES, MJ;NARA, PL
用定量感染性分析方法研究了sCD4浓度、靶细胞密度和病毒存活期对可溶性CD4封闭活性的影响。在与20 NM sCD4孵育期间，人类免疫缺陷病毒1型(HIV-1)股票发生了不可逆灭活。相反，用2 nM的sCD4灭活几乎完全可逆。在较低的sCD4浓度(小于或等于2 nM)和6.25×10(4)ml-1的靶细胞密度下，sCD4对HIV-1的阻断活性为1.7×10(9)M-1，这与化学测量结果一致。然而，在较高的1.6×10(7)细胞ml-1密度下，阻断活性降低了20倍。在通过快速收获优化了传染性的HIV-1菌株的孵化过程中，sCD4阻断活性在3小时窗口内增加了20倍。这些结果表明，竞争性阻断活性强烈依赖于靶细胞密度和病毒粒子年龄。因此，艾滋病毒库存和检测条件的意外变化可能会阻碍不同实验室对阻滞剂的比较，而艾滋病毒挑战库存的年龄可能会影响药物和疫苗效力的研究。结果还表明，阻断淋巴间隔中的病毒颗粒将需要非常高的竞争性阻滞剂浓度，这可能解释了基于sCD4的药物试验在人类身上产生的难治性结果。
Quantitative infectivity assays were used to study how the blocking activity of soluble CD4 (sCD4) is affected by sCD4 concentration, target cell density, and viral stock age. During incubation with 20 nM sCD4, human immunodeficiency virus type 1 (HIV-1) stocks underwent irreversible inactivation. In contrast, inactivation with 2 nM sCD4 was almost entirely reversible. At lower sCD4 concentrations (less-than-or-equal-to 2 nM) and target cell densities of 6.25 x 10(4) ml-1, sCD4 blocking activity for HIV-1 gave a gp120-sCD4 association constant (K(assoc)) of 1.7 x 10(9) M-1, which agrees with chemical measurements. At the higher density of 1.6 x 10(7) cells ml-1, however, the blocking activity was 20-fold less. During incubation of HIV-1 stock optimized for infectivity by rapid harvest, sCD4 blocking activity increased 20-fold during a 3-h window. These results show that competitive blocking activity depends strongly on target cell density and virion age. Thus, unappreciated variations in HIV stocks and assay conditions may hinder comparisons of blockers from laboratory to laboratory, and the age of HIV challenge stocks may influence studies of drug and vaccine efficacy. The results also suggest that blocking of viral particles in lymphoid compartments will require very high competitive blocker concentrations, which may explain the refractory outcomes from sCD4-based drug trials in humans.