International Journal of Nanomedicine (Aug 2025)

Adenovirus Nanoparticles Displaying RBD Induce a Protective Immune Response Against BA.5 in Mice

  • Mo C,
  • Wang Z,
  • Liu D,
  • Yang X,
  • Zhang Q,
  • Ye L,
  • Yuan S,
  • Deng S,
  • Lai Z,
  • Huang D,
  • Yang Y,
  • Xu D,
  • Yuan J,
  • Zhu Y,
  • Liu H,
  • Zhou C,
  • Liao X,
  • Li X,
  • Liu W,
  • Zhou R,
  • Tian X

Journal volume & issue
Vol. Volume 20, no. Issue 1
pp. 9771 – 9785

Abstract

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Chuncong Mo,1,2,* Zhongfang Wang,1,2,* Donglan Liu,2,* Xiaoyun Yang,2,* Qiong Zhang,2 Lihua Ye,1 Shuai Yuan,3 ShiDong Deng,1 Zhulan Lai,2 Deyi Huang,1 Yujie Yang,1,2 Duo Xu,2 Jinwei Yuan,2 Yuhui Zhu,1 Haoyi Liu,1 Chengxing Zhou,2 Xiaohong Liao,2 Xiao Li,1 Wenkuan Liu,1 Rong Zhou,1,2 Xingui Tian1 1State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, National Clinical Research Center for Respiratory Disease, National Center of Respiratory Medicine, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, Guangdong Province, 510182, People’s Republic of China; 2Guangzhou National Laboratory, Guangzhou, Guangdong Province, 510005, People’s Republic of China; 3Health and Quarantine Laboratory, Guangzhou Customs District Technology Center, Guangzhou, Guangdong Province, 510700, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xingui Tian, Email [email protected] Rong Zhou, Email [email protected]: Adenovirus (Ad) vectors demonstrated significant efficacy as vaccine vectors during the COVID-19 pandemic. Hexon is the major capsid protein, and multiple hypervariable regions (HVRs) have been used for displaying exogenous antigens and inducing a strong antibody responses.Methods: We utilized SpyCatcher/SpyTag technology to incorporate SpyTag into HVR2, 4, and 7 of the hexon of the bivalent vaccine strain rAd3/7, respectively, to construct recombinant Ad, rAd3/7-SpyTag. The receptor-binding domain (RBD) of the SARS-CoV-2 BA5.2 strain fused with SpyCatcher was expressed as SpyCatcher-RBD, Spycatcher-RBD and rAd3/7-SpyTag were incubated in vitro to prepare a novel nanoparticle vaccine candidate, rAd3/7-SpyRBD, against SARS-CoV-2. Characterize rAd3/7-SpyRBD using Western blot, ELISA, transmission electron microscopy (TEM), and particle size measurement, and verify its immunogenicity through mouse immunization.Results: We have successfully established a universal nanoparticle vaccine platform, rAd3/7-SpyTag, and the RBD protein was successfully displayed on the surface of rAd3/7-SpyTag. Compared with SpyCatcher-RBD, rAd3/7-SpyRBD can rapidly induce the production of antibodies and stronger immune responses. Both Spycatcher-RBD and rAd3/7-SpyRBD provide a protective immune response against BA.5 in mouse model mice and can be used as candidates for SARS-CoV-2 vaccine. We also found that rAd3/7-SpyRBD induced the production of neutralizing antibodies against Ad3 and Ad7, suggested that it could serve as an Ads vaccine candidate.Conclusion: We developed a universal nanoparticle vaccine platform and obtained a trivalent vaccine candidate rAd3/7-SpyRBD, against SARS-CoV-2, Ad3, and Ad7, and this is the first time to use SpyCatcher/SpyTag technology in a bivalent rAd3/7 vector for trivalent immunity.Keywords: adenovirus, SARS-CoV-2, nanoparticles, vaccine, SpyTag

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