A Bacterially-Expressed Recombinant Envelope Protein from Usutu Virus Induces Neutralizing Antibodies in Rabbits

Kinga Böszörményi, Janet Hirsch, Gwendoline Kiemenyi Kayere, Zahra Fagrouch, Nicole Heijmans, Roberto Rodriguez Garcia, Soesjiel Dwarka, Amy van Dijke, Boyd Aaldijk, Ronald Limpens, Montserrat Barcena, Bram Koster, Babs Verstrepen, Willy Bogers, Clemens Kocken, Gesine Cornellissen, Ernst Verschoor, Bart Faber

Usutu virus (USUV) is a flavivirus that uses mosquitos as vectors and birds as amplifying hosts. USUV can also cause infections in humans and infection can be associated with mild to severe symptoms. Development of an efficacious vaccine would therefore be highly desirable. Here, we describe the production of the USUV E protein in E.coli, its purification, and the characterization of the expression product. Immunizations of two rabbits with the refolded E-protein fraction, mixed with a strong adjuvant, resulted in the generation of neutralizing antibodies. Interestingly, neutralizing titers were also observed against the closely related West Nile Virus. The results are promising and warrant further research into the efficacy of this potential USUV vaccine.

Published February 2021 in Vaccines