The newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlights the urgent need for assays that detect protective levels of neutralizing antibodies. We studied the relationship among anti-spike ectodomain (anti-ECD), anti–receptor-binding domain (anti-RBD) IgG titers, and SARS-CoV-2 virus neutralization (VN) titers generated by 2 in vitro assays using convalescent plasma samples from 68 patients with COVID-19. We report a strong positive correlation between both plasma anti-RBD and anti-ECD IgG titers and in vitro VN titers. The probability of a VN titer of ≥160, the FDA-recommended level for convalescent plasma used for COVID-19 treatment, was ≥80% when anti-RBD or anti-ECD titers were ≥1:1350. Of all donors, 37% lacked VN titers of ≥160. Dyspnea, hospitalization, and disease severity were significantly associated with higher VN titer. Frequent donation of convalescent plasma did not significantly decrease VN or IgG titers. Analysis of 2814 asymptomatic adults found 73 individuals with anti-ECD IgG titers of ≥1:50 and strong positive correlation with anti-RBD and VN titers. Fourteen of these individuals had VN titers of ≥1:160, and all of them had anti-RBD titers of ≥1:1350. We conclude that anti-RBD or anti-ECD IgG titers can serve as a surrogate for VN titers to identify suitable plasma donors. Plasma anti-RBD or anti-ECD titers of ≥1:1350 may provide critical information about protection against COVID-19 disease.
Eric Salazar, Suresh V. Kuchipudi, Paul A. Christensen, Todd Eagar, Xin Yi, Picheng Zhao, Zhicheng Jin, S. Wesley Long, Randall J. Olsen, Jian Chen, Brian Castillo, Christopher Leveque, Dalton Towers, Jason Lavinder, Jimmy Gollihar, Jose Cardona, Gregory Ippolito, Ruth Nissly, Ian Bird, Denver Greenawalt, Randall M. Rossi, Abhinay Gontu, Sreenidhi Srinivasan, Indira Poojary, Isabella M. Cattadori, Peter J. Hudson, Nicole M. Josleyn, Laura Prugar, Kathleen Huie, Andrew Herbert, David W. Bernard, John M. Dye, Vivek Kapur, James M. Musser
Usage data is cumulative from August 2023 through August 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 1,792 | 76 |
150 | 33 | |
Figure | 154 | 8 |
Table | 107 | 0 |
Supplemental data | 48 | 2 |
Citation downloads | 58 | 0 |
Totals | 2,309 | 119 |
Total Views | 2,428 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.