Liposome-Mediated Delivery of MERS Antigen Induces Potent Humoral and Cell-Mediated Immune Response in Mice.

Masood Alam Khan,Ajamaluddin Malik,Abdulmohsen M Alruwetei,Bader Y Alhatlani,Arif Khan,Osamah Al Rugaie,Mohammad A Alzohairy

doi:10.3390/molecules27020403

Abstract

The advancements in the field of nanotechnology have provided a great platform for the development of effective antiviral vaccines. Liposome-mediated delivery of antigens has been shown to induce the antigen-specific stimulation of the humoral and cell-mediated immune responses. Here, we prepared dried, reconstituted vesicles (DRVs) from DPPC liposomes and used them as the vaccine carrier system for the Middle East respiratory syndrome coronavirus papain-like protease (DRVs-MERS-CoV PLpro). MERS-CoV PLpro emulsified in the Incomplete Freund’s Adjuvant (IFA-MERS-CoV PLpro) was used as a control. Immunization of mice with DRVs-MERS-CoV PLpro did not induce any notable toxicity, as revealed by the levels of the serum alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) in the blood of immunized mice. Immunization with DRVs-MERS-CoV PLpro induced greater antigen-specific antibody titer and switching of IgG1 isotyping to IgG2a as compared to immunization with IFA-MERS-CoV PLpro. Moreover, splenocytes from mice immunized with DRVs-MERS-CoV PLpro exhibited greater proliferation in response to antigen stimulation. Moreover, splenocytes from DRVs-MERS-CoV PLpro-immunized mice secreted significantly higher IFN-γ as compared to splenocytes from IFA-MERS-CoV PLpro mice. In summary, DRVs-MERS-CoV PLpro may prove to be an effective prophylactic formulation to prevent MERS-CoV infection.

Highlights

In the last two decades, the appearance of severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1), the Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has posed a serious threat to the existence of human population across the world [1]
The level of IL-4 was found to be 352 ± 51 pg/mL in the supernatant of splenocytes from mice immunized with Incomplete Freund’s Adjuvant (IFA)-MERS-CoV Papain-like Protease (PLpro) as compared to an IL-4 level of 376 ± 66 pg/mL in mice immunized with DRVs-MERS-CoV PLpro (Figure 5B)
Various nanoparticles, including the Virosomes, Poly(lactide-co-glycolide) nanoparticles, liposomes, and nano-emulsions have been implicated as promising vaccine carriers and immunoadjuvants [26,27,28,29,30]

Summary

Introduction

In the last two decades, the appearance of severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1), the Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has posed a serious threat to the existence of human population across the world [1]. A successful vaccine against MERS-CoV infection should be able to activate neutralizing antibodies and antigen-specific T-cell responses. It should be safe and should not induce toxic manifestations in immunized individuals. Recombinant MERS-CoV and viral-vector-based vaccines have been shown to induce both humoral and cell-mediated immune responses. They were effective in reducing the MERS-CoV infection in animal models [8]. MERS-CoV PLpro deubiquitinates interferon regulatory factor 3 (IRF3) and suppresses the production of interferon β (IFN-β) [18] It is considered a very important drug target in order to develop effective therapeutic agents [19]. The outcomes showed that liposome-encapsulated MERS-PLpro induced stronger antigen-specific antibody and T cell responses in mice

Materials

Preparation and Characterization of DRVs

Immunization of Mice

Characterization of DRVs

Discussion