Abstract

The filoviruses, Marburg and Ebola viruses, cause lethal hemorrhagic fever. Marburg and Ebola virus has caused several outbreaks claiming the lives of thousands of people. No approved post-exposure drugs or vaccines exist for filovirus infection. Several crystal structures of Ebola and Marburg virus surface glycoprotein in complex with neutralizing antibodies are now available. These antibodies target either the receptor binding site (RBS) or the membrane proximal external region (MPER) of the viral surface glycoprotein. Using this structural information, our goal is to design filovirus vaccine candidates and a pool of neutralizing antibodies for therapeutic development.

Project Update

Identify and sequence-optimize natural Abs that neutralize filoviruses:

For this purpose, we have computationally screened the Abs repertoire of previously infected and naïve humans for Abs that are likely neutralizing filoviruses. We employed a rapid structure-based search of large sequence databases using position-specific scoring matrices to identify novel human Abs that are close in sequence and structure to the neutralizing antibodies (Figure 1). Next, we will re-engineer the sequence likely neutralizing Abs to maximize affinity thereby increasing potency and breadth. This helped us understand the structural determinants of human Abs neutralizing filoviruses by binding either to MPER or RBSs, imparting the critical knowledge for designing therapeutics

Epitope-focused antigen design:

With the knowledge of structural determinants of Abs critical for filovirus neutralization, we used scaffolding methods in Rosetta to engineer antigens that resemble MPER of viral glycoprotein. Libraries of these computationally designed immunogens will be screened in vitro and will be biophysically and biochemically validated. The antibody response to these immunogens will be tested in mice and guinea pigs.

Mentors:

Primary Advisor: Jens Meiler

Co-advisor: James Crowe

List of publications:

*Sangha AK, *Bender, BJ et al. Protocols for Molecular Modeling with Rosetta3 and RosettaScripts. Biochemistry 55, 4748–4763 (2016).

Sangha AK, Jinhui D et al. Role of non-local interactions between CDR loops in binding affinity of MR78 antibody to Marburg virus glycoprotein. Structure 25, 1-9 (2017).

*Authors contributed equally to this work