College of Life Sciences, Northeast Normal University, Changchun, China.
Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.
Front Immunol. 2024 Oct 1;15:1427284. doi: 10.3389/fimmu.2024.1427284. eCollection 2024.
With the prevalence of sequentially-emerged sublineages including BA.1, BA.2 and BA.5, SARS-CoV-2 Omicron infection has transformed into a regional epidemic disease. As a sublineage of BA.5, the BA.5.2.48 outbroke and evolved into multi-subvariants in China without clearly established virological characteristics. Here, we evaluated the virological characteristics of two isolates of the prevalent BA.5.2.48 subvariant, DY.2 and DY.1.1 (a subvariant of DY.1). Compared to the normal BA.5 spike, the double-mutated DY.1.1 spike demonstrates efficient cleavage, reduced fusogenicity and higher hACE2 binding affinity. BA.5.2.48 demonstrated enhanced airborne transmission capacity than BA.2 in hamsters. The pathogenicity of BA.5.2.48 is greater than BA.2, as revealed in Omicron-lethal H11-K18-hACE2 rodents. In both naïve and convalescent hamsters, DY.1.1 shows stronger fitness than DY.2 in hamster turbinates. Thus regional outbreaking of BA.5.2.48 promotes the multidirectional evolution of its subvariants, gaining either enhanced pathogenicity or a fitness in upper airways which is associated with higher transmission.
随着 BA.1、BA.2 和 BA.5 等相继出现的亚谱系的流行，SARS-CoV-2 奥密克戎感染已转变为区域性传染病。作为 BA.5 的一个亚谱系，BA.5.2.48 爆发并在中国演变成多种亚变体，没有明确的病毒学特征。在这里，我们评估了流行的 BA.5.2.48 亚变体 DY.2 和 DY.1.1（DY.1 的一个亚变体）的两个分离株的病毒学特征。与正常的 BA.5 刺突相比，双突变的 DY.1.1 刺突表现出有效的切割、降低的融合性和更高的 hACE2 结合亲和力。BA.5.2.48 在仓鼠中的空气传播能力比 BA.2 更强。与 BA.2 相比，BA.5.2.48 的致病性更强，这在奥密克戎致死性 H11-K18-hACE2 啮齿动物中得到了证实。在未感染和恢复期的仓鼠中，DY.1.1 在仓鼠鼻甲中的适应性强于 DY.2。因此，BA.5.2.48 的区域性爆发促进了其亚变体的多方向进化，获得了更高的致病性或上呼吸道的适应性，这与更高的传播性有关。
