Costantini Veronica P, Nguyen Kenny, Lyski Zoe, Novosad Shannon, Bardossy Ana C, Lyons Amanda K, Gable Paige, Kutty Preeta K, Lutgring Joseph D, Brunton Amanda, Thornburg Natalie J, Brown Allison C, McDonald L Clifford, Messer William, Vinjé Jan
Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA;
Oak Ridge Institute for Science and Education, Oak Ridge, TN.
J Immunol. 2022 Mar 15;208(6):1500-1508. doi: 10.4049/jimmunol.2100934. Epub 2022 Feb 28.
Oral fluids offer a noninvasive sampling method for the detection of Abs. Quantification of IgA and IgG Abs in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG Abs against the prefusion-stabilized form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein expressed in suspension-adapted HEK-293 cells. Normalization against total Ab isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 prepandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA, 95.5%; IgG, 89.7%) without compromising specificity (IgA, 99%; IgG, 97%). No cross-reactivity with endemic coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/ml and 0.30 ng/ml, respectively. Salivary IgA and IgG Abs were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary Ab titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 wk in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.
口腔液提供了一种用于检测抗体的非侵入性采样方法。对唾液中的IgA和IgG抗体进行定量分析，有助于研究自然感染或接种疫苗后的黏膜和全身免疫反应。我们开发并验证了一种酶免疫测定法（EIA），用于检测和定量针对在悬浮适应的HEK-293细胞中表达的严重急性呼吸综合征冠状病毒2（SARS-CoV-2）刺突蛋白预融合稳定形式的唾液IgA和IgG抗体。针对总抗体同种型进行标准化，以考虑样本差异，如采集时间和样本体积。对从2个队列中纳入的187例SARS-CoV-2确诊病例采集的唾液样本以及373份大流行前的唾液样本进行了检测。两种EIA的敏感性都很高（IgA为95.5%；IgG为89.7%），且不影响特异性（IgA为99%；IgG为97%）。未观察到与地方性冠状病毒的交叉反应。SARS-CoV-2唾液IgA和IgG检测的检测限分别为1.98 ng/ml和0.30 ng/ml。轻度COVID-19症状患者唾液中的IgA和IgG抗体比重症患者更早被检测到。然而，重症患者的唾液抗体滴度高于轻度感染患者。轻度病例中，唾液IgA滴度在6周后迅速下降，但在重症病例中至少到第10周仍可检测到。无论疾病严重程度如何，所有患者的唾液IgG滴度都保持在较高水平。总之，IgA和IgG的EIA对确认当前或近期SARS-CoV-2感染以及评估IgA和IgG免疫反应具有高特异性和敏感性。
