Yamamoto Atsuko, Hayasaki-Kajiwara Yoko, Baba Takamichi, Okaga Saori, Kakui Mayumi, Shishido Takao
Laboratory for Drug Discovery and Disease Research, Shionogi & Co, Ltd, Osaka, Japan.
Biostatistics Center, Shionogi & Co, Ltd, Osaka, Japan.
Influenza Other Respir Viruses. 2024 Dec;18(12):e70058. doi: 10.1111/irv.70058.
Evaluation of infectious virus titer is a challenge for respiratory syncytial virus (RSV) clinical trials because of the labile nature of RSV and rapid loss of infectivity without proper specimen handling. However, there has been no rigorous investigation into RSV stability in clinical specimens.
RSV stability was investigated by evaluating virus titers and defined as titer variation from baseline within three standard deviations of our titration assay. RSV stability in viral transport medium (VTM) at 4°C and the effect of freezing method on stability were evaluated using RSV-A2 stock. RSV stability in nasal aspirates collected in VTM at 4°C was estimated by regression analysis of virus titers measured at several time points. Stability of these specimens stored at -80°C for 10-15 months after freezing by the method, which maintained RSV-A2 stability, was also assessed.
Three standard deviations were calculated from our titration assay as 0.97 log 50% tissue culture infectious dose (TCID/mL), and RSV stability was defined as variation of virus titer from baseline within 1.0 logTCID/mL. RSV-A2 in VTM at 4°C was stable for at least 120 h. Freezing at -80°C negatively affected virus stability, whereas freezing in liquid nitrogen or a dry ice-ethanol bath did not. RSV in nasal aspirates was stable for 2 days at 4°C and for 10-15 months at -80°C after snap freezing.
RSV in nasal aspirates in VTM was estimated to be stable for 2 days at 4°C and for approximately 1 year at -80°C.
由于呼吸道合胞病毒（RSV）性质不稳定，且在标本处理不当的情况下感染力会迅速丧失，因此评估传染性病毒滴度对RSV临床试验来说是一项挑战。然而，尚未对临床标本中RSV的稳定性进行严格研究。
通过评估病毒滴度来研究RSV的稳定性，并将其定义为滴定测定三个标准差范围内相对于基线的滴度变化。使用RSV-A2储备液评估RSV在4°C病毒运输培养基（VTM）中的稳定性以及冷冻方法对稳定性的影响。通过对在多个时间点测得的病毒滴度进行回归分析，估算在4°C下收集于VTM中的鼻吸出物中RSV的稳定性。还评估了采用能维持RSV-A2稳定性的方法冷冻后，这些标本在-80°C下储存10 - 15个月的稳定性。
根据我们的滴定测定，计算出三个标准差为0.97 log 50%组织培养感染剂量（TCID/mL），RSV稳定性定义为病毒滴度相对于基线的变化在1.0 logTCID/mL以内。4°C下VTM中的RSV-A2至少120小时内稳定。-80°C冷冻对病毒稳定性有负面影响，而在液氮或干冰 - 乙醇浴中冷冻则没有。鼻吸出物中的RSV在4°C下2天内稳定，速冻后在-80°C下10 - 15个月内稳定。
VTM中鼻吸出物内的RSV估计在4°C下2天内稳定，在-80°C下约1年内稳定。
