Development and Preliminary Characterization of a Baculovirus Pseudotyped with Andes Virus Envelope Glycoproteins

Hantaviruses infect a range of animal hosts, with rodents serving as reservoirs and transmitting the virus to humans through aerosols of their secretions and excretions. These zoonotic infections can lead to Hantavirus Cardiopulmonary Syndrome (HCPS), which in Chile and Argentina is caused by the Andes virus (ANDV). ANDV is particularly concerning due to its >40% mortality rate and unique capacity for person‑to‑person transmission. To date, no vaccine or therapeutic has been approved by the FDA or equivalent agencies.

In this work, the GPC gene fragment of ANDV, which encodes the envelope glycoproteins Gn and Gc, was integrated into the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) genome using the MultiBac system. The construct was designed for dual expression under the polyhedrin (Polh) promoter for insect cells and the CMV promoter for mammalian cells. Although the GPC fragment was placed under both promoters, only robust expression under Polh has been confirmed, guiding current optimization efforts for mammalian expression. The resulting pseudotyped baculovirus showed strong expression and was successfully amplified to titers exceeding 10⁸ in Sf21 and Sf9 insect cells. The presence and localization of the glycoproteins were confirmed by Western blot using hybridoma-derived monoclonal antibodies and by indirect immunofluorescence assay (IFA). Ongoing work includes immunogold electron microscopy to visualize the ANDV´s glycoproteins on the virion surface and inoculation studies in Syrian hamsters to evaluate immunogenicity and neutralizations activity. While current experimental efforts may prove encouraging, they will be critical for establishing the immunogenic potential of the system and confirming its relevance as a vaccine platform. Although baculovirus-based pseudotyped vaccine candidates have been developed for other pathogens, this system represents a novel application in the context of ANDV. Its modular design and engineering flexibility may further support adaptation for antigen delivery or evaluation in other emerging infectious diseases.