tetano
Editor, Senior Moderator
Protein Eng Des Sel
. 2023 Aug 10;gzad008.
doi: 10.1093/protein/gzad008. Online ahead of print. The variable conversion of neutralizing anti-SARS-CoV-2 single chain antibodies to IgG provides insight into RBD epitope accessibility
Matthew R Chang[SUP] 1 [/SUP], Hanzhong Ke[SUP] 1 2 [/SUP], Laura Losada Miguéns[SUP] 1 [/SUP], Christian Coherd[SUP] 1 [/SUP], Katrina Nguyen[SUP] 1 [/SUP], Maliwan Kamkaew[SUP] 1 [/SUP], Rebecca Johnson[SUP] 2 [/SUP], Nadia Storm[SUP] 2 [/SUP], Anna Honko[SUP] 2 [/SUP], Quan Zhu[SUP] 1 3 [/SUP], Anthony Griffiths[SUP] 2 [/SUP], Wayne A Marasco[SUP] 1 3 [/SUP]
Affiliations
Monoclonal antibody (mAb) therapies have rapidly become a powerful class of therapeutics with applications covering a diverse range of clinical indications. Though most widely used for the treatment of cancer, mAbs are also playing an increasing role in the defense of viral infections, most recently with palivizumab for prevention and treatment of severe respiratory syncytial virus infections in neonatal and pediatric populations. In addition, during the COVID-19 pandemic, mAbs provided a therapeutic bridge to the rollout of vaccines; however, their continued role as a therapeutic option for those at greatest risk of severe disease has become limited due to the emergence of neutralization resistant Omicron variants. Although there are many techniques for the identification of mAbs, including single B cell cloning and immunization of genetically engineered mice, the low cost, rapid throughput and technological simplicity of antibody phage display has led to its widespread adoption in mAb discovery efforts. Here we used our 27-billion-member naïve single-chain antibody single-chain variable fragment (scFv) phage library to identify a panel of neutralizing anti-severe acute respiratory syndrome coronavirus 2 scFvs targeting diverse epitopes on the receptor binding domain (RBD). Although typically a routine process, we found that upon conversion to immunoglobulin G, a number of our most potent clones failed to maintain their neutralization potency. Kinetic measurements confirmed similar affinity to the RBD; however, mechanistic studies provide evidence that the loss of neutralization is a result of structural limitations likely arising from initial choice of panning antigen. Thus this work highlights a risk of scFv-phage panning to mAb conversion and the importance of initial antigen selection.
Keywords: SARS-CoV-2; antibody discovery; neutralizing antibodies; phage display; phage panning.
. 2023 Aug 10;gzad008.
doi: 10.1093/protein/gzad008. Online ahead of print. The variable conversion of neutralizing anti-SARS-CoV-2 single chain antibodies to IgG provides insight into RBD epitope accessibility
Matthew R Chang[SUP] 1 [/SUP], Hanzhong Ke[SUP] 1 2 [/SUP], Laura Losada Miguéns[SUP] 1 [/SUP], Christian Coherd[SUP] 1 [/SUP], Katrina Nguyen[SUP] 1 [/SUP], Maliwan Kamkaew[SUP] 1 [/SUP], Rebecca Johnson[SUP] 2 [/SUP], Nadia Storm[SUP] 2 [/SUP], Anna Honko[SUP] 2 [/SUP], Quan Zhu[SUP] 1 3 [/SUP], Anthony Griffiths[SUP] 2 [/SUP], Wayne A Marasco[SUP] 1 3 [/SUP]
Affiliations
- PMID: 37561410
- DOI: 10.1093/protein/gzad008
Monoclonal antibody (mAb) therapies have rapidly become a powerful class of therapeutics with applications covering a diverse range of clinical indications. Though most widely used for the treatment of cancer, mAbs are also playing an increasing role in the defense of viral infections, most recently with palivizumab for prevention and treatment of severe respiratory syncytial virus infections in neonatal and pediatric populations. In addition, during the COVID-19 pandemic, mAbs provided a therapeutic bridge to the rollout of vaccines; however, their continued role as a therapeutic option for those at greatest risk of severe disease has become limited due to the emergence of neutralization resistant Omicron variants. Although there are many techniques for the identification of mAbs, including single B cell cloning and immunization of genetically engineered mice, the low cost, rapid throughput and technological simplicity of antibody phage display has led to its widespread adoption in mAb discovery efforts. Here we used our 27-billion-member naïve single-chain antibody single-chain variable fragment (scFv) phage library to identify a panel of neutralizing anti-severe acute respiratory syndrome coronavirus 2 scFvs targeting diverse epitopes on the receptor binding domain (RBD). Although typically a routine process, we found that upon conversion to immunoglobulin G, a number of our most potent clones failed to maintain their neutralization potency. Kinetic measurements confirmed similar affinity to the RBD; however, mechanistic studies provide evidence that the loss of neutralization is a result of structural limitations likely arising from initial choice of panning antigen. Thus this work highlights a risk of scFv-phage panning to mAb conversion and the importance of initial antigen selection.
Keywords: SARS-CoV-2; antibody discovery; neutralizing antibodies; phage display; phage panning.