Antivirals and vaccines against arenavirus infections
Michael J. Buchmeier, UC Irvine
Arenaviruses are rodent-borne pathogens that cause significant morbidity and mortality in humans. Pathogenic arenaviruses include Lassa (LASV), lymphocytic choriomeningitis (LCMV), Junin (JUNV), Machupo (MACV), Guanarito (GTOV), Sabia (SABV) and Whitewater Arroyo (WWAV) viruses. Following human infection with the Old World arenaviruses LCMV or LASV, cellular immunity plays a pivotal role in viral clearance and protective immunity. Therefore, it is important to develop sensitive reagents to measure the cell-mediated immune response in the context of human infection or vaccine studies. The identification of HLA-restricted epitopes is required to develop assays that can be used to determine the quality of immune responses, define correlates of protection and immunopathology, and ultimately guide the selection of candidate vaccines. This project utilizes bioinformatic predictions to identify candidate epitopes, in vitro binding assays and in vivo immunogenicity studies in transgenic mice to validate vaccine candidates and determine if they are protective against viral challenge.
Targeting the entry pathway of New World arenaviruses for anti-viral therapeutics
Paula M. Cannon, University of Southern California
The clade B New World arenaviruses contain several severe human pathogens, including the causative agents of Argentine, Bolivian and Venezuelan hemorrhagic fevers. Limited information is available about the molecular biology of these viruses. We are interested in the entry step of the viral life cycle, whereby the surface glycoprotein (GP) of these viruses binds to a cellular receptor and triggers fusion between the virus and the host cell membrane. At present, the cellular receptor(s) used by the pathogenic clade B viruses is unknown. Furthermore, the domains in GP that are involved in binding to the receptor and triggering fusion are also unknown. A greater understanding of these functional components would greatly facilitate the development of therapeutics targeted specifically to this stage of the viral life cycle. We are using a variety of approaches to identify the clade B cell surface receptor(s) including genetic complementation cloning of receptor-defective cells and GP-receptor immunoprecipitations. Simultaneously, we are using mutagenesis and binding assays to define domains within GP that are needed to bind to the receptor, and thereby identify a minimal receptor-binding domain within GP
Nipah and Hendra virus entry and budding
Benhur Lee, UC Los Angeles
Nipah and Hendra viruses are lethal paramyxoviruses that require high levels of containment. This project uses a Vesicular Stomatitis Virus (VSV) reporter platform to study the structural virology of the hanipaviral fusion cascade and develop high throughput assays to detect neutralizing and/or cross-reactive antibodies for diagnostics, surveillance, and vaccine development at less than BSL4 levels. The underlying rationale for the proposed studies is that serum neutralization assays and structural virology studies done with our VSV-rluc (Renilla luciferase) reporter pseudotypes will provide biologically relevant information more efficiently and economically than using their live viral counterparts. To accomplish our stated objectives, we propose the following specific aims: (1) to gain a supramolecular nanoscale understanding of the henipavirus fusion cascade using cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET) to visualize Nipah virus F and G oligomers pseudotyped onto VSV; (2) to study relevant serum samples from the Global Viral Forecasting Initiative using our henipavirus VSV pseudotypes; and (3) to use a beta-lactamase-Nipah matrix based assay for sensitive, specific and high throughput analysis of native henipavirus entry and budding at BSL2 conditions.