Negeviruses reduce replication of alphaviruses during co-infection

Negeviruses are a group of insect-specific virus (ISV) that have been found in many arthropods. Their presence in important vector species led us to examine their interactions with arboviruses during co-infections. Wild-type negeviruses reduced the replication of Venezuelan equine encephalitis virus (VEEV) and chikungunya virus (CHIKV) during co-infections in mosquito cells. Negev virus (NEGV) isolates were also used to express GFP and anti-CHIKV antibody fragments during co-infections with CHIKV. NEGV expressing anti-CHIKV antibody fragments was able to further reduce replication of CHIKV during co-infections, while reductions of CHIKV with NEGV expressing GFP were similar to titers with wild-type NEGV alone. These results are the first to show that negeviruses induce superinfection exclusion of arboviruses, and to demonstrate a novel approach to deliver anti-viral antibody fragments with paratransgenic ISVs. The ability to inhibit arbovirus replication and express exogenous proteins in mosquito cells make negeviruses a promising platform for control of arthropod-borne pathogens.