This project will develop Immunotherapeutics for Biodefense against Lassa virus (LASV), an arenavirus that is the causative agent of Lassa fever (LF). LASV is a Biosafety Level 4 and NIAID Biodefense category A agent. LF is a major public health concern causing widespread loss of life and social disruption across West Africa. The goal of this proposal is to perform critical steps in the characterization and pre-clinical development of a new class of therapeutics to treat LF. This effort combines the expertise of virologists and immunologists at Tulane University and the University of Texas Medical Branch with scientists at Zalgen, a biotechnology company specialized in the development of immunotherapeutics, rapid diagnostics, and new vaccine platforms for emerging viral diseases with global impact. Studies proposed here will leverage our recent advances, including identification of lead candidate human monoclonal antibodies (huMAbs) that neutralize LASV infectivity and protect guinea pigs against fatal disease induced by LASV. Zalgen's exclusive technology for rapid development (<3 months) of high yield antibody expressing stable cell lines ensures that costs of producing therapeutic antibodies is minimized for primary Biodefense markets and secondary Public Health markets. In studies proposed in MILESTONE 1 we will generate multi-milligram quantities of IgG1 and IgG4 LASV huMAb subtypes in serum-free medium adapted mammalian cell transient expression platforms for purification to perform in vitro testing. We will also perform a panel of characterization assays with the huMAbs focusing on identification of a huMAb or combinations of huMAbs with broad LASV neutralization potential and low IC50. Additional studies will establish cross-reactivity profiles with related Ne and Old World arenaviral proteins and reactivity of LASV huMAbs with human cell membrane phospholipids. In MILESTONE 2 we will generate CHO or NS0 stable cell lines in chemically defined serum free medium and select high producing isolates. Limiting dilution cell cloning (LDCC) will be performed for isolation of stable, production grade CD-SFM-CHO or CD-SFM-NS0 clones. We also plan to generate Accession Cell Banks (ACB) for clonal cell lines of interest, and to convert to manufacturing with QA/QC to generate gram quantities of candidate huMAbs for in vivo studies. In MILESTONE 3 we will perform evaluation of pharmacokinetics of LASV huMAb subtypes in guinea pigs (GPs). We will also perform challenge - therapeutic dose finding studies with two lead candidate LASV huMAbs or huMAb combinations in GPs, following a single dose via optimal delivery route. Next, we will determine the therapeutic efficacy with LASV huMAbs or huMAb combinations in Good Laboratory Practice (GLP) GP studies throughout the course of a lethal infection timeline, via the optimally determined route of administration. Results of the GP studies will guide an evaluation of pharmacokinetics of two single LASV huMAbs (IgG1 or IgG4) or huMAb combinations in a GLP nonhuman primate (NHP) study, following a single intravenous, intraperitoneal, or subcutaneous dose. We will also perform therapeutic efficacy studies with LASV huMAbs or huMAb combinations in GLP NHP studies throughout the course of a lethal infection timeline, following two doses via optimal delivery route, at varying times post infection. This proposed effort will result in a new class of immunotherapeutics for LF.
The objective of this project is to create a safe, well tolerated, and effective drug that will treat or prevent Lassa fever, a severe and often-fatal disease that is a major biowarfare threat. Lassa fever is common is some parts of West Africa and therefore unlike many other biothreat agents Lassa virus would be easy to obtain and disseminate to developed countries. Recently, we isolated human antibodies that block infectivity of the Lassa virus and now we propose to use modern molecular biology techniques to generate and modify these antibodies in the laboratory in order to develop a much-needed commercial product.
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