Antibody binding to SARS-CoV-2 S glycoprotein correlates with, but does not predict neutralization

• In this study Shilei Ding et al analyze how neutralization relates to binding of the Spike (S) in the context of viral or pseudoviral particles by a pseudovirus capture assay (VCA)  previously developed by this same group and a neutralization assay.  

• As it has been reported, although convalescent plasma therapy as some antibodies targeting S might potentially neutralize viral and pseudoviral particles, there is a proportion that won’t. What they demonstrate is that the capacity of antibodies to bind the S glycoprotein at the surface of viral particles ir required but not sufficient to mediate neutralization.  

• Here they show the importance of the interaction between antibody and S in neutralization. Thus, it should be taken in consideration in the development of new vaccines. 

Research Highlights

1.  Recognition of S glycoproteins at the surface of pseudoviral particles is required but no sufficient to neutralize 

2.  The decrease in neutralization over time might be due to the disappearance of antibodies able to recognize the S glycoprotein at the surface of viral particles. 

Impact for COVID-19 research:  

• Although this report do not alter our point of view of Covid-19, it does show how virus neutralization might vary depending on S binding which should be considered when using plasma from convalescent patients as a treatment 

Methodologies: 

• Study Type: in vitro. 

• Important cell lines/viral models used: Plasmids: Spike of SARS-CoV-2/1; pNL4.3 R-E-Luc: VSV-G-encoding plasmid (pSVCMV-IN-VSV-G). Cell lines: Cf2Th cells and 293T-ACE2 cell line  

• Key Techniques: Virus capture assay to measure the capacity of plasma samples and monoclonal ab. Neutralization assay using sera.  

Limitations: 

• Might have been worth it to do a time curse to analyze when ab/plasma lose the ability to bind the S glycoprotein. 

• Compare neutralization ability plasma and ab.