Evaluation of immune response in BALB/c mice generated by SARS-CoV-2 membrane-envelope virus-like particles

In late December 2019, SARS-CoV-2 emerged in Wuhan, China. Since then, several variants have been identified. The delta variant, a variant of concern, originated in Lucknow, India. Since then, there has been an urgent need to develop effective therapeutics and vaccine candidates against SARS-CoV-2. Virus-Like Particles (VLPs) are promising vaccine candidates. The advantage of VLP-based vaccines is that they resemble viral structures. In this study, we developed SARS-CoV-2 Virus-Like Particles. The docking and MD simulations analysis confirmed the presence of strong interactions between M and E proteins. The purified VLPs were confirmed by TEM and FESEM, with a size range of 100-120 nm. Immunization of BALB/c mice with purified VLPs elicited a strong immune response, as measured by ELISA. The immunized mice serum showed high titers of IgG, IgM, and IFN-γ. qRT-PCR cytokine analysis showed a Th1/Th2 response. The virus-neutralization assay confirmed the presence of neutralizing antibodies in the sera of immunized mice. These results show that VLP-based vaccines can be effective against SARS-CoV-2 and constitute a scalable, safe, and effective vaccine platform.