RP4: Monoclonal antibodies against henipaviruses, arenaviruses, and nairoviruses

PROJECT SUMMARY/ABSTRACT - RP4 (Monoclonal Antibodies against Henipaviruses, Arenaviruses and Nairoviruses) The paramyxoviruses, nairoviruses, and arenaviruses represent collections of diverse virus species, and these groups of viruses are ideal for prototype pathogen immunity approaches. The goal of developing medical countermeasures is to confer protective immunity, which can be provided by active immunization (as in RP1 and RP2 here) or by passive immunization with long-acting (90-day half-life) monoclonal antibodies (mAbs). In this RP4, we will used several different state-of-the-art antibody discovery approaches to isolate and engineer optimal mAbs for these 3 major groups of viruses. Virus-immune B cells will be interrogated with several well- developed human mAb discovery platforms, including high-throughput single cell sorting and single cell RNAseq techniques, or converted to stable human hybridoma cell lines. B cell line supernatants or recombinant mAbs will be subjected to high-throughput screening to identify Abs that bind to virus surface proteins and functionally inhibit virus replication. Our objectives include determining the principles governing optimal mAb combinations and synergy, developing new in vitro selection methods to enhance antibody neutralization potency and breadth, and genetically modifying mAbs for extended-half-life properties to enable the use of injections of long-lived antibodies to confer protective immunity and protection like that of vaccines. Lessons learned in the year 1 to 3 studies of the prototype pathogens Lassa, Machupo, Crimean-Congo hemorrhagic fever, Hendra, and Nipah viruses will be applied to new discovery campaigns for related viruses in the same family or genera, as a model for applying "plug and play" Test Cases for the prototype pathogen approach. Identifying antibodies to the related pathogens, will validate the prototype pathogens approach, preparing us for an unexpected epidemic of a previously unknown paramyxovirus, nairovirus, or arenavirus. Also, these programs will isolate promising medical countermeasures for additional potential causes of future epidemics. Further, incorporating screens for wide breadth of recognition in these studies may enable identification of pan-family or pan-genus antibodies that can but used for multiple related agents, including future related pathogens for which we have not yet specifically prepared. Identifying major sites of vulnerability on the virus surface proteins for recognition by neutralizing and/or protective antibodies also will be useful for our consortium partners working on antigen design. Prioritized mAbs then will be tested for therapeutic efficacy in multiple animal models of infection including nonhuman primates. The leads will be selected, and CHO cell lines will be made by Mapp Biopharmaceutical for Ab production, in preparation for cGMP manufacture and IND planning. The work promises to yield best-in-class mAb combinations for broad and potent activity against three groups of viruses that can be used to treat or prevent human virus infections. These studies will identify protective/neutralizing epitopes of mAbs through structural studies of antigen-Ab complexes that inform immunogen design in RP1/RP2 using rational vaccine antigen design approaches.