Aptamers Targeting Rabies Virus Inhibit Viral Replication Both In Vitro And In Vivo

Rabies is a fatal central nervous system (CNS) infectious disease affecting manywarm-blooded mammals. Human rabies is caused by infection with rabies virus (RABV). Whilepost-exposure immunization strategies are available to treat RABV-infected patients, they arelargely ineffective once the virus has invaded the CNS. Rabies continues to be a worldwide humanhealth threat, causing an estimated55,000deaths annually. Hence, there is an urgent need toidentify and develop alternative therapeutic strategies to treat rabies virus infections.Despite the relative infancy of the aptamer field, aptamers have been introduced into clinicaluse. In order to select the aptamers with potential against RABV, a cell surface-systematicevolution of ligands by exponential enrichment (Cell-SELEX) strategy was established. andDNA aptamers targeted to intact rabies infected BHK-21cells were generated. Through35iterative rounds of Cell-SELEX selection, DNA aptamers, which targeted to intact rabies infectedBHK-21cells were identified. All of the aptamers’ were determined to form stem-loop structures.Virus titer assay and quantitative reverse transcription (qRT-)PCR revealed that aptamers couldcould specifically inhibit the replication of RABV in cultured baby hamster kidney (BHK)-21cells, but that aptamers FO21and FO24were most effective, but did not inhibit the replication ofcanine distemper virus (CDV) or canine parvovirus (CPV).Then we established RVG-BHK-21cells, which expressed RABV glycoprotein on theBHK-21cell surface. We performed a SELEX procedure for the isolation of aptamers, whichtargeted RVG-BHK-21cells and could could specifically inhibit the replication of RABV incultured baby hamster kidney (BHK)-21cells, the GE54was most effective, but did not inhibit thereplication of canine distemper virus (CDV) or canine parvovirus (CPV).To test whether the aptamers inhibit virus replication and protect mice challenged by RABVin vivo, groups of8female BALB/c mice six to eight weeks of age were challenged by CVS-11orFJ strain in the absence or presence of aptamers. When mice were inoculated with aptamers for24h prior to inoculation with CVS-11, best group was approximately80%of the mice survived but GE54was approximately40%. Even mice challenged by street virus (FJ strain), mice couldsurvive.Collectively, these data show the feasibility of generating functionally effective aptamersagainst rabies virus-infected cells by the Cell-SELEX iterative procedure. Aptamers couldsignificantly protect the mice from a lethal dose of RABV in vitro and in vivo, as demonstrated bythe results for survival rate, weight lossand viral titers. These aptamers have proved to beclinically useful as therapeutic molecules with specific antiviral potential against RABVinfections.