Treuhaft M W
J Gen Virol. 1983 Jun;64 (Pt 6):1301-9. doi: 10.1099/0022-1317-64-6-1301.
A colorimetric assay for defective interfering (DI) particles of respiratory syncytial (RS) virus was developed. This quantitative biological assay is based on neutral red dye uptake by DI particle-protected cells that survive standard virus challenge. This assay was more sensitive than the reduction of infectious yield (RIY) assay and was capable of detecting 1 X 10(4) to 2 X 10(4) DI particles/ml. The coefficient of variation for parallel, simultaneous replicates (n = 10) was 23%. Cell-protecting activity in the colorimetric assay appeared simultaneously with activity in the RIY assay on undiluted passage of plaque-purified virus. Both activities were particulate, were inactivated by RS virus antiserum and exhibited similar ultraviolet-inactivation kinetics. The absolute values of the slopes of dilution curves for both assays were similar, and using regression analysis both assays enabled estimation of similar numbers of active particles. These results suggest that both activities are mediated by the same DI particle. The mechanism of cell protection does not appear to involve extracellular interferon because the inclusion of interferon antibody in the assay did not diminish DI particle cell protection. Finally, the colorimetric assay was used to reveal alternating cycles of infectious and DI virus production on serial undiluted passage.
开发了一种用于呼吸道合胞体（RS）病毒缺陷干扰（DI）颗粒的比色测定法。这种定量生物学测定法基于在标准病毒攻击下存活的、由DI颗粒保护的细胞对中性红染料的摄取。该测定法比感染性产量降低（RIY）测定法更灵敏，能够检测到1×10⁴至2×10⁴个DI颗粒/毫升。平行、同时重复实验（n = 10）的变异系数为23%。在对空斑纯化病毒进行未稀释传代时，比色测定法中的细胞保护活性与RIY测定法中的活性同时出现。两种活性均为颗粒性，可被RS病毒抗血清灭活，并表现出相似的紫外线灭活动力学。两种测定法稀释曲线斜率的绝对值相似，并且通过回归分析，两种测定法都能够估算出相似数量的活性颗粒。这些结果表明，两种活性均由相同的DI颗粒介导。细胞保护机制似乎不涉及细胞外干扰素，因为在测定法中加入干扰素抗体并不会降低DI颗粒对细胞的保护作用。最后，比色测定法被用于揭示在连续未稀释传代中感染性病毒和DI病毒产生的交替循环。
