Gamaleya National Research Centre for Epidemiology and Microbiology, Moscow 123098, Russia.
Russian Medical Academy of Continuing Professional Education "RMANPO", Moscow 125993, Russia.
Viruses. 2022 May 15;14(5):1053. doi: 10.3390/v14051053.
Bovine coronaviruses (BCoVs), which cause gastrointestinal and respiratory diseases in cattle, and are genetically related to the human coronavirus HCoV-OC43, which is responsible for up to 10% of common colds, attract increased attention. We applied the method of photodynamic inactivation with cationic photosensitizers (PSs) to reduce the titers of BCoV and studied the morphological structure of viral particles under various modes of photodynamic exposure. The samples of virus containing liquid with an initial virus titer of 5 Log TCID50/mL were incubated with methylene blue (MB) or octakis(cholinyl)zinc phthalocyanine (Zn-PcChol) at concentrations of 1-5 μM for 10 min in the dark at room temperature. After incubation, samples were irradiated with LED (emission with maximum at 663 nm for MB or at 686 nm for Zn-PcChol) with light doses of 1.5 or 4 J/cm. Next, the irradiation titrated virus containing liquid was studied using negative staining transmission electron microscopy. MB and Zn-PcChol at concentrations of 1-5 μM, in combination with red light from LED sources in the low doses of 1.5-4.0 J/cm, led to a decrease in BCoV titers by at least four orders of magnitude from the initial titer 5 Log TCID50/mL. Morphological changes in photodamaged BCoVs with increasing PS concentrations were loss of spikes, change in shape, decreased size of virus particles, destruction of the envelope, and complete disintegration of viruses. BCoV has been found to be sensitive to MB, which is the well-known approved drug, even in the absence of light.
牛冠状病毒（BCoVs）可引起牛的胃肠道和呼吸道疾病，与导致高达 10%普通感冒的人类冠状病毒 HCoV-OC43 在基因上有关，因此引起了更多关注。我们应用光动力失活法，用阳离子光敏剂（PS）来降低 BCoV 的滴度，并研究了在各种光动力暴露模式下病毒粒子的形态结构。用初始病毒滴度为 5 Log TCID50/mL 的含病毒液体样本与亚甲蓝（MB）或八（胆碱基）锌酞菁（Zn-PcChol）在黑暗室温下于 1-5 μM 浓度下孵育 10 分钟。孵育后，用 LED（MB 的最大发射波长为 663nm，Zn-PcChol 的最大发射波长为 686nm）以 1.5 或 4 J/cm 的光剂量进行照射。接下来，用负染色透射电子显微镜研究照射滴定含病毒液体。MB 和 Zn-PcChol 在 1-5 μM 的浓度下，与 LED 光源的低剂量 1.5-4.0 J/cm 的红光结合，可使 BCoV 的滴度至少降低 4 个数量级，从初始滴度 5 Log TCID50/mL 开始。随着 PS 浓度的增加，光损伤的 BCoVs 的形态变化为刺突丢失、形状改变、病毒粒子大小减小、包膜破坏和病毒完全解体。即使在没有光照的情况下，牛冠状病毒也被发现对 MB 敏感，MB 是一种已被批准的药物。
