Table 1.
Memory B cell recall response in participants who lost their seropositive status after vaccination or infection.
| Participant | Total IgG | Total ASCs | Cal/09 IgG | RBD IgG | Spike IgG | Spike ASCs | |
|---|---|---|---|---|---|---|---|
| Normal responders | CVI-004 | + | + | + | + | + | + |
| P-073 | + | + | + | + | + | + | |
| Non-responders | CTR-351 | + | − | − | − | − | − |
| CVI-499 | + | + | − | − | − | − | |
| CVI-623 | + | − | − | − | |||
| CVI-732 | + | − | − | − | − | − | |
| Lost seroprotection post-vaccination | CVI-256 | + | + | − | +/− | +/− | + |
| CVI-313 | + | + | + | + | + | + | |
| MHC-031 | + | + | + | + | |||
| P-055 | + | + | + | + | + | + | |
| P-068 | + | + | + | + | + | + | |
| P-134 | + | + | + | + | + | + | |
| CTR-212 | + | + | − | − | − | − | |
| CVI-237 | + | + | + | +/− | +/− | − | |
| CVI-519 | + | − | + | +/− | +/− | − | |
| STM-064 | + | + | − | − | |||
| Lost seroprotection post-infection | P-164 | + | + | + | − | − | − |
| VTH-002 | + | + | − | − | |||
| P-014 | + | − | − | − |
Differentiated PBMC supernatants from the post-waned timepoints were tested for total IgG antibody levels, as well as IgG antibodies specific to A/H1N1/California/2009 pandemic influenza strain. In addition, the total number of IgG ASCs and the spike-specific ASCs were enumerated from differentiated PBMCs. The + symbol represents the presence of de novo recalled antibodies or ASCs; − represents the absence of de novo recalled antibodies or ASCs, +/− represents that the results were dissimilar based on the two times the experiment was repeated using different PBMC vials. Normal responders seroconverted as expected, nonresponders failed to seroconvert after vaccination, lost seroprotection groups initially seroconverted after vaccination or infection but later lost seroprotective status as shown by a lack of both RBD-binding and SARS-CoV-2 neutralizing antibodies.