Virus-Mimicking Nanovaccination Fights Lethal MERS-CoV Infection

Middle East respiratory syndrome coronavirus (MERS-CoV) infection is a highly lethal emerging zoonotic disease that is transmitted from camels to humans. Since the first identified case of MERS in 2012 in Saudi Arabia, there have been over 2,000 confirmed cases across 27 countries globally. The disease has a high mortality rate of over 34% and there is no vaccine or treatment available against the pathogen. As MERS-CoV is identified as one of the priority diseases by the World Health Organization, there is an urgent need for new vaccine technology against the pathogen. An international consortium comprised of scientists from the University of Texas Medical Branch (UTMB), National Taiwan University, and Academia Sinica has developed a novel nanoparticle vaccine mimicking the morphology of MERS-CoV against the infectious pathogen. The nanoparticle vaccine has proven to be safe and effective against a lethal challenge of MERS-CoV in a transgenic mouse model.

Due to the highly mutational nature of many emerging diseases, effective prophylactic strategies demand multidisciplinary collaborations for innovative solutions. The nanoparticle vaccine development was supported by the National Taiwan University and Academia Sinica Innovative Joint Program and the Ministry of Science and Technology of Taiwan, and the preclinical testing was performed at the biosafety level 3 laboratory at UTMB. By integrating the receptor binding domain of MERS-CoV with a capsid-like polymeric nanoshell loaded with a potent immunologic adjuvant, a highly potent nanoparticle vaccine can be prepared. In a mouse model, the vaccine stimulated a high and durable level of anti-MERS-CoV antibodies that can neutralize MERS-CoV antigens. In addition, the vaccine also triggered an elevated level of antigen-specific T cells, which is critical for MERS-CoV protection. In a study with live MERS-CoV challenge, mice vaccinated with the nanoparticle vaccine showed 100% survival whereas all the non-vaccinated mice succumbed to the lethal challenge. Unlike live attenuated virus vaccines, the nanoparticle vaccine demonstrates superior safety and is comprised entirely of biocompatible materials. The international team aims to assess the nanoparticle vaccine in non-human primates before moving to clinical trials.

The international consortium is led by Prof. Chien-Te Kent Tseng at UTMB’s Department of Microbiology and Immunology, Prof. Hui-Wen Chen (陳慧文) at NTU’s Department of Veterinary Medicine, and Dr. Che-Ming Jack Hu (胡哲銘) at the Institute of Biomedical Sciences, Academia Sinica. The paper presenting the results entitled “Viromimetic STING Agonist-Loaded Hollow Polymeric Nanoparticles for Safe and Effective Vaccination against Middle East Respiratory Syndrome Coronavirus” was published online in the journal Advanced Functional Materials on April 12th, 2019. doi:10.1002/adfm.201807616.