Open AccessA novel anti‐HIV‐1 bispecific bNAb‐lectin fusion protein engineered in a plant‐based transient expression system
Author(s) -
Seber Kasinger Lauren E.,
Dent Matthew W.,
Mahajan Garima,
Hamorsky Krystal Teasley,
Matoba Nobuyuki
Publication year - 2019
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.13090
Subject(s) - virology , glycan , biology , antibody , fusion protein , chimera (genetics) , nicotiana benthamiana , integrase , virus , neutralization , viral envelope , c type lectin , lectin , glycoprotein , microbiology and biotechnology , human immunodeficiency virus (hiv) , biochemistry , immunology , recombinant dna , gene
Summary The discovery of broadly neutralizing antibodies (bNAbs) has been a major step towards better prophylactic and therapeutic agents against human immunodeficiency virus type 1 (HIV‐1). However, effective therapy will likely require a combination of anti‐HIV agents to avoid viral evasion. One possible solution to this problem is the creation of bispecific molecules that can concurrently target two vulnerable sites providing synergistic inhibitory effects. Here, we describe the production in plants and anti‐HIV activity of a novel bispecific fusion protein consisting of the antigen‐binding fragment (Fab) of the CD4 binding site‐specific bNAb VRC01 and the antiviral lectin Avaren, which targets the glycan shield of the HIV‐1 envelope (VRC01 Fab ‐Avaren). This combination was justified by a preliminary experiment demonstrating the synergistic HIV‐1 neutralization activity of VRC01 and Fc‐fused Avaren dimer (Avaren‐Fc). Using the GENEWARE ® tobacco mosaic virus vector, VRC01 Fab ‐Avaren was expressed in Nicotiana benthamiana and purified using a three‐step chromatography procedure. Surface plasmon resonance and ELISA demonstrated that both the Avaren and VRC01 Fab moieties retain their individual binding specificities. VRC01 Fab ‐Avaren demonstrated enhanced neutralizing activity against representative HIV‐1 strains from A, B and C clades, compared to equimolar combinations of VRC01 Fab and Avaren. Notably, VRC01 Fab ‐Avaren showed significantly stronger neutralizing effects than the bivalent parent molecules VRC01 IgG and Avaren‐Fc, with IC 50 values ranging from 48 to 310 p m . These results support the continued development of bispecific anti‐HIV proteins based on Avaren and bNAbs, to which plant‐based transient overexpression systems will provide an efficient protein engineering and production platform.