Longitudinal antibody titer, avidity, and neutralizing responses after SARS-CoV-2 infection

• Published in: Heliyon Vol. 8; no. 11; p. e11676
• Main Authors: Monroe, Jonathon M., Haralambieva, Iana H., Warner, Nathaniel D., Grill, Diane E., Quach, Huy Quang, Kennedy, Richard B.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2022; Published by Elsevier Ltd; Elsevier
• Subjects: Antibody avidity; COVID-19; Humoral immunity; Longitudinal immunity; Neutralization; SARS-CoV-2; COVID-19; Longitudinal immunity; SARS-CoV-2; Antibody avidity; Humoral immunity; Neutralization
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2022.e11676

While waning immunity and SARS-CoV-2 variant immune escape continue to result in high infection rates worldwide, associations between longitudinal quantitative, qualitative, and functional humoral immune responses after SARS-CoV-2 infection remain unclear. In this study, we found significant waning of antibody against Spike S1 (R = −0.32, p = 0.035) and N protein (R = −0.39, p = 0.008), while RBD antibody moderately decreased (R = −0.19, p = 0.203). Likewise, neutralizing antibody titer (ND50) waned over time (R = −0.46, p = 0.001). In contrast, antibody avidity increased significantly over time for Spike S1 (R = 0.62, p = 6.0e−06), RBD (R = 0.54, p = 2.0e−04), and N (R = 0.33, p = 0.025) antibodies. Across all humoral responses, ND50 strongly associated with Spike S1 (R = 0.85, p = 2.7e−13) and RBD (R = 0.78, p = 2.9e−10) antibodies. Our findings provide longitudinal insight into humoral immune responses after infection and imply the potential of Spike S1/RBD antibody titer as surrogate correlates of protection. SARS-CoV-2; COVID-19; Antibody avidity; Neutralization; Humoral immunity; Longitudinal immunity.