成人接种2剂新冠灭活疫苗12个月后T细胞免疫应答特点

Characteristics of T cell immune responses in adults inoculated with 2 doses of SARS-CoV-2 inactivated vaccine for 12 months

目的评估成年人接种新型冠状病毒(SARS-CoV-2)灭活疫苗12个月后不同抗原特异性T细胞免疫应答的特点。方法解放军总医院第五医学中心2022年4-6月招募15名健康成年人,于接种2剂新冠灭活疫苗12个月后采集其静脉血标本,以基于多色流式细胞术的活化诱导标记法(AIM)检测SARS-CoV-2抗原特异性T淋巴细胞水平,并分析其记忆表型与亚群分化特点。结果成年人接种2剂灭活疫苗12个月后,90%以上个体可检测到Spike及Non-spike特异性CD4^(+)T细胞反应(S:14/15,P=0.0001;NS:15/15,P<0.0001);80%个体检测到Spike及Non-spike特异性CD8^(+)T细胞反应(S:12/15,P=0.0463;NS:12/15,P=0.0806)。抗原特异性CD4^(+)T细胞主要表现为中央记忆细胞(CM)、1型效应记忆细胞(EM1)记忆表型,以及1/17型辅助性T细胞(Th1/17)、2型辅助性T细胞(Th2)辅助表型。结论灭活疫苗接种后能诱导广泛且持久的抗原特异性CD4^(+)T细胞反应,可能是当前国内新型冠状病毒感染重症化比例较低的关键因素。

Objective To evaluate the characteristics of different antigen-specific T cell immune responses to severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)after inoculation with 2 doses of SARS-CoV-2 inactivated vaccine for 12 months.Methods Fifteen healthy adults were enrolled in this study and blood samples collected at 12 months after receiving two doses of SARS-CoV-2 inactivated vaccine.The level and phenotypic characteristics of SARS-CoV-2 antigen-specific T lymphocytes were detected by activation-induced markers(AIM)based on polychromatic flow cytometry.Results After 12 months of inoculation with 2 doses of SARS-CoV-2 inactivated vaccine,more than 90%of adults had detectable Spike and Non-spike antigen-specific CD4^(+)T cells immune responses(Spike:14/15,P=0.0001;Non-spike:15/15,P<0.0001).80%of adults had detectable Spike and Non-spike antigen-specific CD8^(+)T cells immune responses(Spike:12/15,P=0.0463;Non-spike:12/15,P=0.0806).Antigen-specific CD4^(+)T cells induced by SARS-CoV-2 inactivated vaccination after 12 months were composed of predominantly central memory(CM)and effector memory 1(EM1)cells.On the other hand,in terms of helper subsets,antigen-specific CD4^(+)T cells mainly showed T helper 1/17(Th1/17)and T helper 2(Th2)phenotypes.Conclusions SARS-CoV-2 inactivated vaccination generates durable and extensive antigen-specific CD4^(+)T cell memory responses,which may be the key factor for the low proportion of severe coronavirus disease 2019(COVID-19)infection in China.