Multivalent messenger ribonucleic acid-lipid nanoparticle vaccine against SARS-CoV-2

Recent articles posted on bioRxiv* The preprint server analyzed a multivalent messenger ribonucleic acid (mRNA) -lipid nanoparticle (LNP) vaccine construct against a specific β-coronavirus (β-CoV).

Background

Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome-Related CoV (MERS-CoV), and Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) all have significant mortality rates worldwide. It is β-CoV showing. .. The SARS-CoV-2 mRNA-based Moderna and Pfizer-BioNTech CoV Disease 2019 (COVID-19) vaccine experience approved in 2020/2021 underscores the need for rapid deployment of better vaccines for successful management measures. doing.

The emergence of highly pathogenic and infectious SARS-CoV-2 variants with improved antigenic escape enhances immunity to numerous SARS-CoV-2 variants against various members of the current pandemic and β-CoV families. It emphasizes the demand for multivalent vaccines. general.

mRNA vaccines range from being able to be manufactured at a minimal price compared to inactivated virus and protein-based vaccines, being rapidly designed and synthesized, and providing real-time clinical data showing the safety of the mRNA platform in humans. There are advantages. Widely reactive multivalent vaccination is required to prevent immune evasion and to immunize against rapidly evolving viral variants. Recent studies show that homodimerization of β-CoV receptor binding domains (RBDs) enhances their immunogenicity and stability. These findings mean that different β-CoVRBD heterodimers or homodimers may improve the likelihood of inducing cross-reactive cellular and humoral immune responses.

About research

In current research, researchers aimed for multivalent development Coronaviridae A vaccine that can be manufactured and manufactured quickly. The team evaluated the immunogenicity of mice against SARS-CoV after immunization with the original strain of SARS-CoV-2, multiple variant of concern (VOC), and four RBD mRNA-LNP vaccine candidates. These vaccination candidates had SARS-CoV-2 / SARS-CoVRBD heterodimers or homodimers encoded by mRNA. Researchers have found that vaccination is cross-reactivity to the recently discovered SARS-CoV-2 beta (B.1.351) and delta (B.1.617.2) VOCs with donor SARS-CoV-2 and SARS-CoV strains. I investigated how well the antibody was induced. Shows improved antigenic escape.

Researchers have 1) green fluorescent protein (control), 2) SARS-CoV CUHK-W1 RBD (R306–K523), 3) SARS-CoV-2 Wuhan-Hu-1 reference strain RBD (R319-K537). Designed 5 mRNA frameworks to code. ), 4) SARS-CoV / SARS-CoV-2 RBD heterodimer, and 5) SARS-CoV-2RBD homodimer. The mRNA encoding RBD was transfected into human fetal kidney 293T (HEK293T) cells and combined with a lipid mixture tuned to produce LNP. Dynamic light scattering (DLS) was used to quantify the diameters of various RBD mRNA-LNP batches.

On days 0 and 14, a group of male C57BL / 6J mice were injected intramuscularly with 10 g of each vaccine in 80 μL phosphate buffered saline to assess the immunogenicity of RBD mRNA-LNP. .. Blood is drawn from mice 2 weeks after boost and the SARS-CoV and SARS-CoV-2 pure spike (S) protein coated plates are used in a direct-linked enzyme-linked immunosorbent assay (ELISA) to test sera for antibody production. Did.

Results and conclusions

The results of the study showed that transfection of HEK293T cells with RBD-encoding mRNA was high in each recombinant RBD, as verified by Western blot evaluation with cross-reactive anti-SARS-CoV-2 / SARS-CoV RBD antibody. It has been shown to contribute to production.This inference showed that mRNA is translatable In vivo.. The DLS showed minimal variation in diameter between batches, an average particle size of 120 nm, and a size that allowed effective cell absorption and tissue penetration.

In particular, substantial immunoglobulin G (IgG) titers that respond to both S proteins were induced by four RBD mRNA-LNP vaccinations. The monomeric mRNA-LNP responded preferentially to the immune S protein as expected, but the change in titer was not significant. There was no significant difference in mean anti-S protein IgG concentrations induced by the SARS-CoV-2 homodimer and the monomeric mRNA-LNP. This indicated that dimerization did not enhance SARS-CoV-2RBD immunogenicity in the setting of these mRNA-LNP vaccines.

Compared to the other three vaccines, heterodimeric mRNA LNP produced a larger anti-SARS-CoV-2 S protein IgG titer and succeeded in inducing antibodies against the SARS-CoVS protein. Robust and equivalent IgG1 and IgG2a responses to the SARS-CoV-2 S protein are induced by the heterodimer mRNA-LNP and show a balanced type 2 T helper (Th2) / Th1 immune response.

In mRNA-LNP immune animals, the profile of neutralizing antibody production was similar to that found in S protein-binding antibodies. As a result, all four RBD mRNA vaccines produced antibodies that effectively neutralize SARS-CoV-2 and SARS-CoV-based antibodies. Pseudo virus Vero cell infection. Heterodimer and monomeric SARS-CoV-2 mRNA-LNP elicited a similar S-protein binding IgG response, whereas heterodimer vaccination was more effective in eliciting. Neutralizing antibody Towards both stocks.

The ability of serum samples from SARS-CoV-2 heterodimer RBD mRNA immune mice to neutralize serum samples from beta, Wuhan-E484K, and Wuhan-N501Y pseudoviruses was 5.4, 14.5, respectively, compared to Wuhan pseudovirus. And decreased by 2.3 times.Similarly, neutralization Effectiveness Pairs to delta were reduced 11.7-fold in heterodimeric RBD mRNA-induced mouse sera.

In summary, in this study, all vaccine constructs analyzed elicited a significant antiviral antibody response, and heterodimer vaccines crossed SARS-CoV-2 Wuhan-Hu-1, beta, delta variants. It was shown to elicit a sufficient IgG response to neutralize. And SARS-CoV.

*Important Notices

bioRxiv publishes unpeer-reviewed preliminary scientific reports and should not be considered definitive, guide clinical / health-related behaviors, or be treated as established information.