Immunogenicity and Antigenicity of the Recombinant Ectodomain of Rabies Virus Glycoprotein Containing the Human Collagen XVIII Trimerization Domain
Smekenov I. Bayandy G. Alybayev S. Baltakhozha N. Batanova Z. Akhmetsadykov N. Bissenbaev A.
September 2025Multidisciplinary Digital Publishing Institute (MDPI)
Vaccines
2025#13Issue 9
Background: Rabies remains a fatal zoonotic disease, necessitating effective and affordable vaccines. While current vaccines are effective, they require multiple doses and may not induce long-lasting immunity in all settings. The rabies virus glycoprotein (RABV-G) is the principal antigen responsible for eliciting virus-neutralizing antibodies, but its recombinant monomeric forms often suffer from poor immunogenicity due to misfolding and aggregation. Methods: A recombinant trimeric RABV-G ectodomain (rRABV-G-XVIII) was engineered by fusing it to a human collagen XVIII-derived trimerization domain. The protein was expressed in E. coli, purified under denaturing conditions, and refolded. Trimer formation was verified using size-exclusion chromatography. Mice were immunized with rRABV-G-XVIII, with or without adjuvant, and compared to a monomeric form (rRABV-GE). Antigen-specific antibody responses were measured by ELISA, neutralizing activity was assessed, and protective efficacy was evaluated via intracerebral challenge with the CVS-27 rabies strain. Results: rRABV-G-XVIII formed stable trimers and induced strong humoral immune responses, with high ELISA titers and virus-neutralizing activity comparable to an inactivated rabies vaccine. Mice immunized with rRABV-GE showed lower antibody responses and partial protection, which improved with adjuvant. All rRABV-G-XVIII-immunized mice were fully protected against rabies challenge, independent of adjuvant use. Conclusions: Stabilization of RABV-G in its native trimeric conformation markedly improves immunogenicity and protective efficacy. This approach offers a promising strategy for the development of rabies subunit vac-cines with simplified formulations and potential for cost-effective production in bacterial systems.
ELISA , expression , glycoprotein , human collagen XVIII , immunogenicity , mice immunization , rabies , trimeric protein
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Department of Molecular Biology and Genetics, Faculty of Biology and Biotechnology, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Scientific Research Institute of Biology and Biotechnology Problems, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Department of Molecular Biology and Genetics
Scientific Research Institute of Biology and Biotechnology Problems
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