Antibody Affinity Governs the Inhibition of SARS-CoV-2 Spike/ACE2 Binding in Patient Serum.
Sebastian FiedlerMonika A PiziorskaViola DenningerAlexey S MorgunovAlison IlsleyAnisa Y MalikMatthias M SchneiderSean R A DevenishGeorg MeislVasilis KosmoliaptsisAdriano AguzziHeike FieglerTuomas P J KnowlesPublished in: ACS infectious diseases (2021)
The humoral immune response plays a key role in suppressing the pathogenesis of SARS-CoV-2. The molecular determinants underlying the neutralization of the virus remain, however, incompletely understood. Here, we show that the ability of antibodies to disrupt the binding of the viral spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor on the cell, the key molecular event initiating SARS-CoV-2 entry into host cells, is controlled by the affinity of these antibodies to the viral antigen. By using microfluidic antibody-affinity profiling, we were able to quantify the serum-antibody mediated inhibition of ACE2-spike binding in two SARS-CoV-2 seropositive individuals. Measurements to determine the affinity, concentration, and neutralization potential of antibodies were performed directly in human serum. Using this approach, we demonstrate that the level of inhibition in both samples can be quantitatively described using the dissociation constants (KD) of the binary interactions between the ACE2 receptor and the spike protein as well as the spike protein and the neutralizing antibody. These experiments represent a new type of in-solution receptor binding competition assay, which has further potential applications, ranging from decisions on donor selection for convalescent plasma therapy, to identification of lead candidates in therapeutic antibody development, and vaccine development.
Keyphrases
- sars cov
- angiotensin converting enzyme
- angiotensin ii
- binding protein
- immune response
- respiratory syndrome coronavirus
- single cell
- high throughput
- protein protein
- amino acid
- dna binding
- cell therapy
- induced apoptosis
- stem cells
- bone marrow
- risk assessment
- signaling pathway
- climate change
- mesenchymal stem cells
- mass spectrometry
- single molecule
- circulating tumor cells
- coronavirus disease
- cell death
- human health
- zika virus
- pi k akt
- replacement therapy
- transcription factor