Are We Truly Protected - Assessment of Immunity Protection Against Mutating COVID-19 Strains and Assay Development
Abstract
With new viral variants in circulation, we sought to assess whether previously infected soldiers are protected against future SARS-CoV-2 infections by determining if humoral immunity acquired through natural SARS-CoV-2 infection is effective against multiple viral variants. We evaluated the neutralizing capacity of antibodies generated via memory B cells from convalescent patients against five different SARS-CoV-2 variants. PBMCs were stimulated for B cell activation for 6 days and cell supernatants were collected. Plaque reduction neutralization tests (PRNT) were conducted on supernatant samples in 96 well plates seeded with Vero E6 TMPRSS2 cells. In this cohort, some patients were infected with an ancestral virus (40 patients) and others with the more contemporary omicron variant (61 patients). Neutralizing antibody was detected in 10 out of the 40 samples harvested from individuals with ancestral COVID-19 and neutralizing capacity was low, yielding PRNT50 titers at the assay limit of detection (1:2) for 60 of the samples. Samples with higher PRNT50 titers often demonstrated more robust neutralizing activity across multiple variants, with one patient showing activity against the ancestral, beta, delta, and omicron BA.2 strains. Neutralizing antibody was more prevalent in samples harvested from patients infected with more contemporary viral variants, as 59 of samples had detectable PRNT50 titers. Neutralizing titers were also more robust in this cohort, exhibiting titers that were above the assay limit of detection in the majority of positive samples (58 ). These findings suggest that humoral immunity from infection with a more contemporary SARS-CoV-2 variant results in a memory response that is more robust with an increased likelihood of broader coverage against multiple variants compared to immunity stemming from infection with an ancestral strain.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 23, 2024
- Accession Number
- AD1221937
Entities
People
- Alexander J. Burdette
- Ana C. Rojas
- Ashley C Brown
- Kaley C. Hanrahan
- Thomas Gibbons
Organizations
- 59th Medical Wing