Immunology and Allergy Unit, Santa Maria degli Angeli Hospital, Pordenone, Italy.
Laboratory for Hygiene and Public Health, University Hospital of Trieste, Trieste, Italy.
Clin Chim Acta. 2022 Jan 1;524:11-17. doi: 10.1016/j.cca.2021.11.023. Epub 2021 Nov 27.
Long-term kinetics of anti-RBD IgG and neutralizing antibodies were analyzed in a cohort of COVID-19 naïve health care workers (HCW) undergoing SARS-CoV-2 vaccination.
An anti-RBD IgG immunoassay and a surrogate virus neutralization test (sVNT) were performed at different time points up to 6 months after vaccination in 57 HCWs. Values of anti-RBD IgG predicting an high neutralizing bioactivity (>60%) were also calculated.
Mean (range) values of anti-RBD IgG were 294.7 (11.6-1554), 2583 (398-8391), 320.4 (42.3-1134) BAU/mL at T1 (21 days after the 1st dose [T0]), T2 (30 days after the 2nd dose) and T3 (+180 days after T0), respectively. Mean (range) percentages of neutralization (NS%) were 24 (0-76), 86 (59-96) and 82 (52-99) at T1, T2 and T3, respectively. Anti-RBD IgG values and NS% were positively correlated at T2 and T3 while anti-RBD IgG value predicting a NS% > 60 markedly differed at T2 and T3 (594 vs. 108 BAU/mL, respectively).
While a high neutralizing bioactivity was maintained at least 6 months after vaccination in almost all individuals, the mean values of anti-RBD-IgG showed a marked decline at 6 months. The absolute value of anti-RBD IgG is a poor marker of neutralizing bioactivity.
在接受 SARS-CoV-2 疫苗接种的 COVID-19 初治医护人员 (HCW) 队列中，分析了抗 RBD IgG 和中和抗体的长期动力学。
在 57 名 HCW 中，在接种疫苗后不同时间点（长达 6 个月）进行抗 RBD IgG 免疫测定和替代病毒中和试验 (sVNT)。还计算了预测高中和生物活性 (>60%)的抗 RBD IgG 值。
T1（第 1 剂后 21 天 [T0]）、T2（第 2 剂后 30 天）和 T3（T0 后 180 天）时，抗 RBD IgG 的平均值（范围）分别为 294.7（11.6-1554）、2583（398-8391）、320.4（42.3-1134）BAU/mL。T1、T2 和 T3 时的平均中和百分比 (NS%) 分别为 24（0-76）、86（59-96）和 82（52-99）。T2 和 T3 时，抗 RBD IgG 值和 NS% 呈正相关，而 T2 和 T3 时预测 NS%>60 的抗 RBD IgG 值明显不同（594 与 108 BAU/mL）。
在几乎所有个体中，接种疫苗后至少 6 个月仍保持高中和生物活性，但抗 RBD-IgG 的平均值在 6 个月时呈明显下降。抗 RBD IgG 的绝对值是中和生物活性的不良标志物。
