Rapid, High Throughput, Automated Detection Of SARS-Cov-2 Neutralizing Antibodies Against Native-Like Vaccine And Delta Variant Spike Trimers

Abstract

Traditional cellular and live-virus methods for detection of SARS-CoV-2 neutralizing antibodies (nAbs) are labor- and time-intensive, and thus not suited for routine use in the clinical lab to predict vaccine efficacy and natural immune protection. Here, we report the development and validation of a rapid, high throughput method for measuring SARS-CoV-2 nAbs against native-like trimeric spike proteins. This assay uses a blockade of hACE-2 binding (BoAb) approach in an automated digital immunoassay on the Quanterix HD-X platform. BoAb assays using vaccine and delta variant viral strains showed strong correlation with cell-based pseudovirus and live-virus neutralization activity. Importantly, we were able to detect similar patterns of delta variant resistance to neutralization in samples with paired vaccine and delta variant BoAb measurements. Finally, we screened clinical samples from patients with or without evidence of SARS-CoV-2 exposure by a single-dilution screening version of our assays, finding significant nAb activity only in exposed individuals. In principle, these assays offer a rapid, robust, and scalable alternative to time-, skill-, and cost-intensive standard methods for measuring SARS-CoV-2 nAb levels.

Enhanced IgG immune response to COVID‐19 vaccination in patients with sickle cell disease

“…Despite their immunocompromised state, patients with SCD generate a more robust (Figure 1A) IgG response to COVID‐19 vaccines compared to the general population, with similar prevalence of strong neutralizing antibodies (Figure 1B) even after examining natural COVID‐19 infection (Figure 1C,D). Based on correlation between RBD IgG level and BoAb neutralization activity, 12 patients with SCD may also generate a more robust neutralizing antibody response than control. The overall trend of higher IgG level in SCD compared to controls held across demographic and COVID‐19 vaccine‐related characteristics (Figure S1A–F), which suggests that the difference in COVID‐19 vaccine IgG response may reflect SCD‐related characteristics not present in the controls.…”

“…Therefore, the presence of NC‐specific IgG was used as marker of SARS‐CoV‐2 infection. Surrogate neutralization activity was measured by high‐throughput blockade of hACE‐2 binding (BoAb) as previously described, 12 except with two‐point dilution at 1:50 and 1:200 to improve throughput (Data S1). Recombinant viral proteins were derived from wildtype Wuhan‐Hu‐1 (GenBank: MN908947.3).…”