Rational design of a trispecific antibody targeting the HIV-1 Env with elevated anti-viral activity

James J Steinhardt,Javier Guenaga,Mark K Louder,John R Mascola,Andrey Galkin,Chi-I Chiang,Lin Lei,Nicole A Doria-Rose,Robert T Bailer,Andrew B Ward,Hannah L Turner,Sijy O’Dell,Alexander K Andrianov,Krisha Mckee,Yuxing Li

doi:10.1038/s41467-018-03335-4

Abstract

HIV-1 broadly neutralizing antibodies (bNAbs) are being explored as passively administered therapeutic and preventative agents. However, the extensively diversified HIV-1 envelope glycoproteins (Env) rapidly acquire mutations to evade individual bNAbs in monotherapy regimens. The use of a “single” agent to simultaneously target distinct Env epitopes is desirable to overcome viral diversity. Here, we report the use of tandem single-chain variable fragment (ScFv) domains of two bNAbs, specific for the CD4-binding site and V3 glycan patch, to form anti-HIV-1 bispecific ScFvs (Bi-ScFvs). The optimal Bi-ScFv crosslinks adjacent protomers within one HIV-1 Env spike and has greater neutralization breadth than its parental bNAbs. Furthermore, the combination of this Bi-ScFv with a third bNAb recognizing the Env membrane proximal external region (MPER) results in a trispecific bNAb, which has nearly pan-isolate neutralization breadth and high potency. Thus, multispecific antibodies combining functional moieties of bNAbs could achieve outstanding neutralization capacity with augmented avidity.

Highlights

HIV-1 broadly neutralizing antibodies are being explored as passively administered therapeutic and preventative agents
Recent advances in the discovery of broadly neutralizing antibodies targeting the HIV-1 envelope glycoproteins (Env) have awakened great interest in their use as pre-exposure prophylaxis for prevention and as therapeutic agents, in combination with antiretroviral treatment (ART) for HIV remission and eradication1–3. bNAb isolation and characterization has been accelerated via the integration of emerging functional and structural information and new technologies of single B cell sorting and cloning4–9. bNAbs are therapeutically beneficial as they possess high capacity for viral neutralization
We selected bNAbs VRC01 (CD4bs-directed)[8] and PGT121 (V3-base glycan-directed)[9], which neutralize ~90 and 70% of circulating viruses, respectively, as a model system to determine whether a Bi-ScFv could improve breadth and potency over the capacities of the individual bNAbs

Summary

Introduction

HIV-1 broadly neutralizing antibodies (bNAbs) are being explored as passively administered therapeutic and preventative agents. One study showed that swapping the IgG1 hinge for a more flexibly IgG3 hinge lacking disulfide bonds (denoted as IgG3C-) greatly improved the potency of anti-HIV CrossMabs[34] While both the CrossMab and IgG3C- designs have significantly improved the potency and breadth of antibodies against HIV, they only target two epitopes, one corresponding to each antigen-binding Fragment (Fab) arm. This limits the potential increase of avidity that would result from simultaneous engagement of multiple functional moieties. Our approach that combines multi-functional moieties of individual bNAbs with profoundly elevated avidity and cooperative effect of multivalence interactions may be applied to generate superior antibody-based antiviral therapeutics against other infectious agents

Methods

Results

Conclusion