Journal Article

Epitope-focused immunogen design based on the ebolavirus glycoprotein HR2-MPER region

Malherbe, Delphine C., Martina, Cristina E., Sangha, Amandeep K., Meiler, Jens, Binshtein, Elad, Williamson, Lauren E., Zhang, Xuan, Fiala, Brooke, Dong, Jinhui, Sutton, Rachel, Kuzmina, Natalia, King, Neil P., Gilchuk, Pavlo, Nargi, Rachel, Rodriguez, Jessica, Ledwitch, Kaitlyn V., Armstrong, Erica, Crowe, James E., Bukreyev, Alexander, Schoeder, Clara T.

2022

Overview

The three human pathogenic ebolaviruses: Zaire (EBOV), Bundibugyo (BDBV), and Sudan (SUDV) virus, cause severe disease with high fatality rates. Epitopes of ebolavirus glycoprotein (GP) recognized by antibodies with binding breadth for all three ebolaviruses are of major interest for rational vaccine design. In particular, the heptad repeat 2 –membrane-proximal external region (HR2-MPER) epitope is relatively conserved between EBOV, BDBV, and SUDV GP and targeted by human broadly-neutralizing antibodies. To study whether this epitope can serve as an immunogen for the elicitation of broadly-reactive antibody responses, protein design in Rosetta was employed to transplant the HR2-MPER epitope identified from a co-crystal structure with the known broadly-reactive monoclonal antibody (mAb) BDBV223 onto smaller scaffold proteins. From computational analysis, selected immunogen designs were produced as recombinant proteins and functionally validated, leading to the identification of a sterile alpha motif (SAM) domain displaying the BDBV-HR2-MPER epitope near its C terminus as a promising candidate. The immunogen was fused to one component of a self-assembling, two-component nanoparticle and tested for immunogenicity in rabbits. Robust titers of cross-reactive serum antibodies to BDBV and EBOV GPs and moderate titers to SUDV GP were induced following immunization. To confirm the structural composition of the immunogens, solution NMR studies were conducted and revealed structural flexibility in the C-terminal residues of the epitope. Overall, our study represents the first report on an epitope-focused immunogen design based on the structurally challenging BDBV-HR2-MPER epitope.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Animals / Antibodies / Antibodies, Neutralizing / Antibodies, Viral / Antigenic determinants / Antigens / Biology and Life Sciences / C-Terminus / Computer applications / Crystal structure / Dengue fever / Design / E coli / Ebola virus / Ebolavirus / Engineering and Technology / Epitopes / Genetic aspects / Glycoproteins / Hemorrhagic Fever, Ebola / HIV / Human immunodeficiency virus / Immune response / Immunization / Immunogenicity / Medicine and Health Sciences / Monoclonal antibodies / Nanoparticles / NMR / Nuclear magnetic resonance / Peptides / Physical Sciences / Properties / Proteins / Protocol / Rabbits / Research and Analysis Methods / Self assembly / Severe acute respiratory syndrome coronavirus 2 / Structure / Testing / Transplants & implants / Vaccines / Viruses