MAPPING EPITOPES AND RECEPTOR BINDING DETERMINANTS OF LASSA VIRUS GLYCOPROTEIN USING Qβ PHAGE DISPLAY

Abstract

Lassa virus (LASV) is a highly infectious pathogen responsible for Lassa fever, a severe hemorrhagic disease endemic to West Africa. Despite its significant health burden, there are currently no widely available vaccines or effective antiviral treatments. The only surface glycoprotein (GP) of LASV is essential for viral entry and immune recognition, making it a prime target for therapeutic and vaccine development. This study involved the engineering and expression of recombinant phages through gene cloning, phage production, and purification, followed by epitope mapping and receptor-binding assays. Qubevirus (Qβ) phage display technology was used to investigate the immunological and receptor-binding properties of LASV GP complex by displaying three novel overlapping fragments, GPF1, GPF2, and GPF3, on the surface of recombinant phages. These engineered phages were screened for their ability to bind anti-GP antibodies and two known host receptors: lysosomal-associated membrane protein 1 (LAMP1) and α-dystroglycan (α-DG). The results demonstrated that GPF2 and GPF3 fragments exhibited strong reactivity with GP-specific antibodies, indicating the presence of accessible and immunodominant epitopes. In contrast, GPF1 showed minimal antibody binding, suggesting that its epitopes are conformational and not well presented on this system. Notably, GPF2 also displayed robust binding to both LAMP1 and α-dystroglycan, identifying it as a key determinant of receptor interaction and immune recognition. The findings highlight GPF2 as a critical region for both host cell entry and immune targeting. These insights were further supported by ELISA that quantified and confirmed the specificity of receptor binding and epitope exposure. Overall, this research provides valuable information on the antigenic landscape and receptor-binding domains of LASV GP. The use of Qβ phage display enabled precise mapping of functional regions, offering a promising platform for the development of subunit vaccines and antiviral drugs, aiming to block LASV infection.