Significant Spike-Specific IgG and Neutralizing Antibodies in Mice Induced by a Novel Chimeric Virus-Like Particle Vaccine Candidate for Middle East Respiratory Syndrome Coronavirus

Middle East respiratory syndrome coronavirus (MERS-CoV) is a major health concern to the general population, with no available licensed therapeutic or vaccine. Virus-like particles (VLPs) comprise viral structural proteins, which represent a safe and highly immunogenic vaccine delivery platform able to induce potent adaptive immune responses. The study aimed to develop immunogenic chimeric VLPs (cVLPs) against MERS-CoV infection via co-expression of modified Spike (S) of MERS-CoV and M1 of H5N1 in a baculoviral expression system. The results indicated that chimeric MERS VLPs were morphologically similar to native MERS-CoV. Whereafter six-to-eight-week-old female BALB/c mice were intramuscularly injected with 1 μg of cVLPs of MERS-S. ELISA and pseudovirus neutralization assay showed high titers of S protein-specific IgG and neutralizing antibodies were induced by the cVLPs. Hence, the cVLPs are promising prophylactic vaccine candidates against MERS-CoV infections.