Isolation and Characterization of Cross-Neutralizing Human Anti-V3 Single-Chain Variable Fragments (scFvs) Against HIV-1 from an Antigen Preselected Phage Library

Abstract

Recently conducted human phase- I trials showed protective effect of anti-HIV-1 broadly neutralizing antibodies (bnAbs). The V3 region of the HIV-1 envelope is highly conserved as it is the co-receptor binding site, and is highly immunogenic. Recombinant single-chain antibody fragments (scFvs) can serve as potential tools for construction of chimeric/bispecific antibodies that can target different epitopes on the HIV-1 envelope. Previously, we have constructed a V3 specific human scFv phage recombinant library by a combinational approach of Epstein-Barr virus (EBV) transformation and antigen (V3) preselection, using peripheral blood mononuclear cells (PBMCs), from a subtype C HIV-1 infected antiretroviral naive donor. In the present study, by biopanning this recombinant scFv phage library with V3B (subtype B) and V3C (subtype C) peptides, we identified unique cross reactive anti-V3 scFv monoclonals. These scFvs demonstrated cross-neutralizing activity when tested against subtype A, subtype B, and subtype C viruses. Further, molecular modeling of the anti-V3 scFvs with V3C and V3B peptides predicted their sites of interaction with the scFvs, providing insights for future immunogen design studies. A large collection of such monoclonal antibody fragments with diverse epitope specificities can be useful immunotherapeutic reagents along with antiretroviral drugs to prevent HIV-1 infection and disease progression.

Inhalation monoclonal antibody therapy: a new way to treat and manage respiratory infections

“…In recent years, immunotherapy has represented a potential intervention to mitigate virus spread and disease severity. A number of mAbs have been isolated from a variety of sources by utilising different strategies for therapeutics or preventive approaches against infectious viral diseases such as the human cytomegalovirus (Gerna et al 2016 ), influenza (DiLillo et al 2014 ; Tan et al 2016 ; Biswas et al 2020 ), human immunodeficiency virus (Kumar et al 2012 , 2018 , 2019a ; Khan et al 2017 ), respiratory syncytial virus (Tang et al 2019 ), SARS-CoV-2 (Pinto et al 2020 ; Parray et al 2020a ; Schoof et al 2020 ; Perween et al 2021 ), Ebola (Flyak et al 2018 ), Zika (Sapparapu et al 2016 ), rabies (Kim et al 2017 ), HBV (Hong et al 2019 ), and dengue (Durham et al 2019 ). Two of these mAbs are currently approved for the treatment of viral infections; palivizumab for the prevention of respiratory syncytial virus (RSV) infection in high-risk children (Olchanski et al 2018 ); and ibalizumab has been introduced for the treatment of HIV-infected individuals who have acquired multidrug antiretroviral therapy (ART) resistance (Rizza et al 2019 ).…”

The SARS CoV-2 spike directed non-neutralizing polyclonal antibodies cross-react with Human immunodeficiency virus (HIV-1) gp41

“…Neutralization assays were carried out using luciferase reporter cell line (TZM-bl) as previously described by Kumar et al, 2012, 2018 [21] , [22] . In brief, env-pseudotyped molecular clones were incubated with serum antibody dilutions for 60 min at 37°C in a CO 2 incubator and then 10000 TZM-bl cells were added to the virus sera mixture in the presence of 25 μg mL -1 DEAE-dextran (Sigma, Inc.).…”

A broadly neutralising monoclonal antibody overcomes the mutational landscape of emerging SARS-CoV2 variant of concerns

“…In case of titration experiments, puri ed mAbs (100 µL per well) were added as three fold serial dilutions starting with 5 μg mL -1 . Standard protocols of blocking (5% skimmed milk in PBS) and washing of ELISA plates (4 times with PBS-0.05% Tween-20) were followed as described previously 11,12 .…”