A high-throughput screening assay to identify inhibitory antibodies targeting alphavirus release

Several studies have demonstrated neutralizing antibodies to be highly effective against alphavirus infection in animal models, both prophylactically and remedially. In most studies, neutralizing antibodies have been evaluated for their ability to block viral entry in vitro but recent evidence suggests that antibody inhibition through other mechanisms, including viral budding/release, significantly contributes to viral control in vivo for a number of alphaviruses. We describe a BSL-2, cell-based, high-throughput screening system that specifically screens for inhibitors of alphavirus egress using chikungunya virus (CHIKV) and Mayaro virus (MAYV) novel replication competent nano-luciferase (nLuc) reporter viruses. Screening of both polyclonal sera and memory B-cell clones from CHIKV immune individuals using the optimized assay detected several antibodies that display potent anti-budding activity. We describe an "anti-budding assay" to specifically screen for inhibitors of viral egress using novel CHIKV and MAYV nLuc reporter viruses. This BSL-2 safe, high-throughput system can be utilized to explore neutralizing "anti-budding" antibodies to yield potent candidates for CHIKV and MAYV therapeutics and prophylaxis.