评估恢复期晚期患者和疫苗接种者的 SARS-CoV-2 特异性 T 细胞反应：QuantiFERON 和激活诱导标志物检测的比较和联合应用，以及与抗体状态的关系。
Assessing SARS-CoV-2-specific T-cell reactivity in late convalescents and vaccinees: Comparison and combination of QuantiFERON and activation-induced marker assays, and relation with antibody status.
机构信息
Laboratory of Haematology, Transfusion Center, Legnano Hospital, ASST Ovest Milanese, via Papa Giovanni Paolo II, Legnano, Milan, Italy.
Department of Internal Medicine, Legnano and Cuggiono Hospitals, ASST Ovest Milanese, via Papa Giovanni Paolo II, Legnano, Milan, Italy.
出版信息
PLoS One. 2023 May 23;18(5):e0285728. doi: 10.1371/journal.pone.0285728. eCollection 2023.
OBJECTIVES
Monitoring of SARS-CoV-2 spread and vaccination strategies have relied on antibody (Ab) status as a correlate of protection. We used QuantiFERON™ (QFN) and Activation-Induced Marker (AIM) assays to measure memory T-cell reactivity in unvaccinated individuals with prior documented symptomatic infection (late convalescents) and fully vaccinated asymptomatic donors (vaccinees).
METHODS
Twenty-two convalescents and 13 vaccinees were enrolled. Serum anti-SARS-CoV-2 S1 and N Abs were measured using chemiluminescent immunoassays. QFN was performed following instructions and interferon-gamma (IFN-γ) measured by ELISA. AIM was performed on aliquots of antigen-stimulated samples from QFN tubes. SARS-CoV-2-specific memory CD4+CD25+CD134+, CD4+CD69+CD137+ and CD8+CD69+CD137+ T-cell frequencies were measured by flow cytometry.
RESULTS
In convalescents, substantial agreement was observed between QFN and AIM assays. IFN-γ concentrations and AIM+ (CD69+CD137+) CD4+ T-cell frequencies correlated with each other, with Ab levels and AIM+ CD8+ T-cell frequencies, whereas AIM+ (CD25+CD134+) CD4+ T-cell frequencies correlated with age. AIM+ CD4+ T-cell frequencies increased with time since infection, whereas AIM+ CD8+ T-cell expansion was greater after recent reinfection. QFN-reactivity and anti-S1 titers were lower, whereas anti-N titers were higher, and no statistical difference in AIM-reactivity and Ab positivity emerged compared to vaccinees.
CONCLUSIONS
Albeit on a limited sample size, we confirm that coordinated, cellular and humoral responses are detectable in convalescents up to 2 years after prior infection. Combining QFN with AIM may enhance detection of naturally acquired memory responses and help stratify virus-exposed individuals in T helper 1-type (TH1)-reactive (QFNpos AIMpos Abshigh), non-TH1-reactive (QFNneg AIMpos Abshigh/low), and pauci-reactive (QFNneg AIMneg Abslow).
目的
监测 SARS-CoV-2 的传播和疫苗接种策略依赖于抗体（Ab）状态作为保护的相关性。我们使用 QuantiFERON™（QFN）和激活诱导标志物（AIM）检测来测量先前有记录的症状性感染（晚期恢复期）和完全接种疫苗的无症状供体（接种者）的未接种个体的记忆 T 细胞反应。
方法
纳入 22 名恢复期患者和 13 名接种者。使用化学发光免疫分析测定血清抗 SARS-CoV-2 S1 和 N 抗体。按照说明书进行 QFN 检测，通过 ELISA 测定干扰素-γ（IFN-γ）。从 QFN 管中抗原刺激样本的等分试样中进行 AIM 检测。通过流式细胞术测量 SARS-CoV-2 特异性记忆 CD4+CD25+CD134+、CD4+CD69+CD137+和 CD8+CD69+CD137+T 细胞频率。
结果
在恢复期患者中，QFN 和 AIM 检测之间观察到高度一致性。IFN-γ浓度和 AIM+（CD69+CD137+）CD4+T 细胞频率相互关联，与 Ab 水平和 AIM+CD8+T 细胞频率相关，而 AIM+（CD25+CD134+）CD4+T 细胞频率与年龄相关。AIM+CD4+T 细胞频率随感染后时间的增加而增加，而在最近再次感染后，AIM+CD8+T 细胞扩增更大。QFN 反应性和抗 S1 滴度较低，而抗 N 滴度较高，与接种者相比，AIM 反应性和 Ab 阳性率没有统计学差异。
结论
尽管样本量有限，但我们证实，在感染后 2 年内，恢复期患者可检测到协调的、细胞和体液反应。将 QFN 与 AIM 结合使用可能会增强对自然获得的记忆反应的检测，并有助于将病毒暴露个体分层为辅助性 T 细胞 1 型（TH1）反应性（QFNpos AIMpos Abshigh）、非 TH1 反应性（QFNneg AIMpos Abshigh/low）和低反应性（QFNneg AIMneg Abslow）。
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