Microbiology Services, NHS Blood and Transplant, Colindale, UK.
Infection and Immunity, Univeristy College of London, London, UK.
Transfusion. 2022 Jul;62(7):1347-1354. doi: 10.1111/trf.16934. Epub 2022 Jun 2.
The therapeutic benefit of convalescent plasma (CP) therapy to treat COVID-19 may derive from neutralizing antibodies (nAbs) to SARS-CoV-2. To investigate the effects of antigenic variation on neutralization potency of CP, we compared nAb titers against prototype and recently emerging strains of SARS-CoV-2, including Delta and Omicron, in CP donors previously infected with SARS-CoV-2 before and after immunization.
Samples were assayed from previously SARS-CoV-2 infected donors before (n = 17) and after one (n = 43) or two (n = 71) doses of Astra-Zeneca or Pfizer vaccinations. Ab titers against Wuhan/wild type (WT), Alpha, Beta, and Delta SARS-CoV-2 strains were determined by live virus microneutralization assay while titers to Omicron used a focus reduction neutralization test. Anti-spike antibody was assayed by Elecsys anti-SARS-CoV-2 quantitative spike assay (Roche).
Unvaccinated donors showed a geometric mean titer (GMT) of 148 against WT, 80 against Alpha but mostly failed to neutralize Beta, Delta, and Omicron strains. Contrastingly, high GMTs were observed in vaccinated donors against all SARS-CoV-2 strains after one vaccine dose (WT:703; Alpha:692; Beta:187; Delta:215; Omicron:434). By ROC analysis, reactivity in the Roche quantitative Elecsys spike assay of 20,000 U/mL was highly predictive of donations with nAb titers of ≥1:640 against Delta (90% sensitivity; 97% specificity) and ≥1:320 against Omicron (89% sensitivity; 81% specificity).
Vaccination of previously infected CP donors induced high levels of broadly neutralizing antibodies against circulating antigenic variants of SARS-CoV-2. High titer donations could be reliably identified by automated quantitative anti-spike antibody assay, enabling large-scale preselection of high-titer convalescent plasma.
恢复期血浆（CP）治疗 COVID-19 的治疗益处可能源自针对 SARS-CoV-2 的中和抗体（nAb）。为了研究抗原变异对 CP 中和效力的影响，我们比较了先前感染过 SARS-CoV-2 的 CP 供体在接种阿斯利康或辉瑞疫苗之前和之后针对原型和最近出现的 SARS-CoV-2 株，包括 Delta 和奥密克戎株的 nAb 滴度。
从先前感染 SARS-CoV-2 的供体中采集样本，在接种（n=17）或接种一剂（n=43）或两剂（n=71）阿斯利康或辉瑞疫苗之前和之后。通过活病毒微量中和试验测定针对武汉/野生型（WT）、Alpha、Beta 和 Delta SARS-CoV-2 株的 Ab 滴度，而使用焦点减少中和试验测定针对 Omicron 的滴度。通过 Elecsys SARS-CoV-2 定量 Spike 抗体检测试剂盒（罗氏）测定抗刺突抗体。
未接种疫苗的供体对 WT 的几何平均滴度（GMT）为 148，对 Alpha 的 GMT 为 80，但对 Beta、Delta 和 Omicron 株基本无法中和。相比之下，接种一剂疫苗后，接种疫苗的供体对所有 SARS-CoV-2 株均显示出高 GMT（WT：703；Alpha：692；Beta：187；Delta：215；Omicron：434）。通过 ROC 分析，罗氏定量 Elecsys 刺突抗体检测试剂盒中 20,000 U/mL 的反应性高度预测了针对 Delta 的 nAb 滴度≥1:640（90%敏感性；97%特异性）和针对 Omicron 的 nAb 滴度≥1:320（89%敏感性；81%特异性）的捐赠。
先前感染 CP 的供体接种疫苗可诱导针对 SARS-CoV-2 循环抗原变异株的高水平广泛中和抗体。通过自动定量抗刺突抗体检测可以可靠地识别高滴度捐赠者，从而能够大规模预先筛选高滴度恢复期血浆。
