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

Jonathon M Monroe; Iana H Haralambieva; Nathaniel D Warner; Diane E Grill; Huy Quang Quach; Richard B Kennedy

doi:10.1016/j.heliyon.2022.e11676

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

Heliyon. 2022 Nov 19;8(11):e11676. doi: 10.1016/j.heliyon.2022.e11676. eCollection 2022 Nov.

Authors

Jonathon M Monroe¹, Iana H Haralambieva¹, Nathaniel D Warner², Diane E Grill², Huy Quang Quach¹, Richard B Kennedy¹

Affiliations

¹ Mayo Clinic Vaccine Research Group, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.
² Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, USA.

Abstract

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.

Keywords: Antibody avidity; COVID-19; Humoral immunity; Longitudinal immunity; Neutralization; SARS-CoV-2.