Vaccine Efficacy of Self-Assembled Multimeric Protein Scaffold Particles Displaying the Glycoprotein Gn Head Domain of Rift Valley Fever Virus
Department of Virology, Wageningen Bioveterinary Research, 8221 RA Lelystad, The Netherlands
Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany
Boehringer Ingelheim Veterinary Research Center GmbH & Co. KG, 30559 Hannover, Germany
Boehringer Ingelheim, 69007 Lyon, France
Laboratory of Virology, Wageningen University and Research, 6708 PB Wageningen, The Netherlands
Author to whom correspondence should be addressed.
Current address: Department of Viroscience, Erasmus MC, 3015 CN Rotterdam, The Netherlands.
Academic Editor: Nirbhay Kumar
Vaccines 2021, 9(3), 301; https://doi.org/10.3390/vaccines9030301
Received: 19 February 2021 / Revised: 18 March 2021 / Accepted: 20 March 2021 / Published: 23 March 2021
(This article belongs to the Section Vaccines against (re)emerging and Tropical Infections Diseases)
Compared to free antigens, antigens immobilized on scaffolds, such as nanoparticles, generally show improved immunogenicity. Conventionally, antigens are conjugated to scaffolds through genetic fusion or chemical conjugation, which may result in impaired assembly or heterogeneous binding and orientation of the antigens. By combining two emerging technologies—i.e., self-assembling multimeric protein scaffold particles (MPSPs) and bacterial superglue—these shortcomings can be overcome and antigens can be bound on particles in their native conformation. In the present work, we assessed whether this technology could improve the immunogenicity of a candidate subunit vaccine against the zoonotic Rift Valley fever virus (RVFV). For this, the head domain of glycoprotein Gn, a known target of neutralizing antibodies, was coupled on various MPSPs to further assess immunogenicity and efficacy in vivo. The results showed that the Gn head domain, when bound to the lumazine synthase-based MPSP, reduced mortality in a lethal mouse model and protected lambs, the most susceptible RVFV target animals, from viremia and clinical signs after immunization. Furthermore, the same subunit coupled to two other MPSPs (Geobacillus stearothermophilus E2 or a modified KDPG Aldolase) provided full protection in lambs as well.