Long-lasting humoral and cellular memory immunity to vaccinia virus Tiantan provides pre-existing immunity against mpox virus in Chinese population

Min Li,Yaxin Guo,Yao Deng,Wenhui Gao,Baoying Huang,Weiyong Yao,Yingze Zhao,Qing Zhang,Mengkun Huang,Maoshun Liu,Lei Li,Peipei Guo,Jinmin Tian,Xin Wang,Ying Lin,Jinxian Gan,Yuanyuan Guo,Yuechao Hu,Jianing Zhang,Xiaonan Yang,Bingli Shang,Mengjie Yang,Yang Han,Yalan Wang,Peilei Cong,Mengzhe Li,Qiaohong Chu,Danni Zhang,Qihui Wang,Tong Zhang,Guizhen Wu,Wenjie Tan,George F Gao,Jun Liu

doi:10.1016/j.celrep.2023.113609

Abstract

Investigating immune memory to vaccinia virus and pre-existing immunity to mpox virus (MPXV) among the population is crucial for the global response to this ongoing mpox epidemic. Blood was sampled from vaccinees inoculated with vaccinia virus Tiantan (VTT) strain born before 1981 and unvaccinated control subjects born since 1982. After at least 40 years of the inoculation, 60% or 5% VTT vaccinees possess neutralizing antibodies (NAbs) to VTT or MPXV, with at least 50% having Tcell memory to VTT protein antigens. Notably, 46.7% vaccinees show pre-existing Tcell responses to MPXV. Broad pre-existing CD8+ Tcell reactivities to MPXV are detected not only against conserved epitopes but also against variant epitopes between VTT and MPXV. Persistent NAbs and Tcell memory to VTT among vaccinees, along with pre-existing Tcells to MPXV among both vaccinees and the unvaccinated population, indicate a particular immune barrier to mpox.

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