An AAV vaccine targeting the RBD of the SARS-CoV-2 S protein induces effective neutralizing antibody titers in mice and canines

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in catastrophic damage worldwide. Accordingly, the development of powerful, safe, easily accessible vaccines with long-term effectiveness is understood as an urgently needed countermeasure against this ongoing pandemic. Guided by this strong promise of using AAVs, we here designed, optimized, and developed an AAV-based vaccines (including AAV-RBD(max), AAV-RBD(wt), AAV-2xRBD, and AAV-3xRBD) that elicit strong immune responses against the RBD domain of the SARS-CoV-2 S protein. These immunogenic responses have proven long-lived, with near peak levels for at least six months in mice. Notably, the sera immunized with AAV-3xRBD vaccine contains powerful neutralizing antibodies against the SARS-CoV-2 pseudovirus. Further evidence proven that potent specific antibodies could also be elicited in canines after vaccination with AAV-3xRBD vaccine.     

电离辐射通过诱导外泌体的分泌促进宫颈癌Siha细胞上皮间质转化

目的 观察宫颈癌Siha细胞在临床常规分割放疗模式的电离辐射诱导后上皮间质转化(EMT)的发生情况,以及外泌体在此过程中的作用。方法 利用临床常规分割外照射(6 MV-X射线,50 Gy/25次)模式的电离辐射处理宫颈鳞癌细胞系Siha,通过形态学观察、EMT标志物检测和Transwell小室实验评价Siha细胞EMT的发生;分离纯化细胞上清液中外泌体,利用透射电镜、纳米粒径示踪分析(NTA),观察其形态与分泌量;最后加入抑制剂GW4869(10 μmol/L)明确外泌体作用。结果 经电离辐射处理后,存活的Siha细胞发生了EMT现象:梭形间质样细胞出现,上皮标志物E-cadherin表达下调(t=9.66,P<0.05),间质标志物N-cadherin表达上调(t=41.61,P<0.05),Transwell穿膜和穿透基质胶的细胞数目增多(t=6.11、13.22,P<0.05)。此外,辐射诱导后,Siha细胞外泌体分泌增加(t=7.51,P<0.05),而GW4869负性调控后,其细胞外泌体的分泌随之减少(t=7.28,P<0.05),电离辐射诱导的EMT也发生了逆转。结论 临床常规分割放疗模式的电离辐射可通过诱导外泌体的分泌促进宫颈癌Siha细胞上皮间质转化。