Wollner, C. J. | Search bioRxiv

bioRxiv2025

mRNA-LNP Vaccines Encoding for Dengue Optimized prM/ENV Proteins Induce Protective Immunity without ADE

Dengue virus (DENV) is the most common mosquito-borne virus in the world, causing nearly 400 million infections annually, with the number of cases predict to increase over time. Despite this prevalence there are no widely approved vaccine for DENV naive individuals or therapeutics. DENV consists of four distinct serotypes, DENV 1-4, that share 60-70% homology. Development of a safe and efficacious pan-Dengue vaccine has been complicated by the potential of antibody-dependent enhancement, in which cross-reactive non-neutralizing antibodies can enhance infection and disease. We previously demonstrated that a mRNA-LNP encoding for DENV-1 prM and Envelope proteins generates homotypic neutralizing immune responses and protects against a lethal challenge. The DENV-1 vaccine avoided ADE by eliminating the fusion loop (FL), one of the dominant ADE epitopes. Using a similar design methodology, here we present mRNA-LNP prM-E vaccines for DENV 2, 3, and 4. These vaccines maintained the {Delta}FL modifications, but encode a chimeric E protein to improve VLP expression and stability. All three vaccines elicited neutralizing titers of serotype specific antibodies mice and protected against a lethal homotypic DENV challenge. Mutation of the FL lowered ADE in vaccinated mouse sera. We formulated monotypic vaccines into a tetravalent vaccine and evaluated for immunogenicity and protection in mice. The tetravalent vaccine elicited neutralizing humoral responses against all DENV serotypes and protected against lethal challenges. Cumulatively, our monovalent DENV mRNA-LNP vaccines against all DENV serotypes generate protective immunity and lower the potential for ADE, leading to the development of a first-generation ADE-altered tetravalent DENV vaccine.

microbiology↗

bioRxiv2021

A mRNA-LNP vaccine against Dengue Virus elicits robust, serotype-specific immunity

Dengue virus (DENV) is the most common vector-borne viral disease with nearly 400 million worldwide infections each year concentrated in the tropical and subtropical regions of the world. Severe dengue complications are often associated with a secondary heterotypic infection of one of the four circulating serotypes. In this scenario, humoral immune responses targeting cross-reactive, poorly-neutralizing epitopes can lead to increased infectivity of susceptible cells via antibody-dependent enhancement (ADE). In this way, antibodies produced in response to infection or vaccination are capable of contributing to enhanced disease in subsequent infections. Currently, there are no available therapeutics to combat DENV disease, and there is an urgent need for a safe and efficacious vaccine. Here, we developed a nucleotide-modified mRNA vaccine encoding for the membrane and envelope structural proteins from DENV serotype 1 encapsulated into lipid nanoparticles (prM/E mRNA-LNP). Vaccination of mice elicited robust antiviral immune responses comparable to viral infection with high levels of neutralizing antibody titers and antiviral CD4+ and CD8+ T cells. Immunocompromised AG129 mice vaccinated with the prM/E mRNA-LNP vaccine were protected from a lethal DENV challenge. Vaccination with either a wild-type vaccine, or a vaccine with mutations in the immunodominant fusion-loop epitope, elicited equivalent humoral and cell mediated immune responses. Neutralizing antibodies elicited by the vaccine were sufficient to protect against a lethal challenge. Both vaccine constructs demonstrated serotype specific immunity with minimal serum cross-reactivity and reduced ADE compared to a live DENV1 viral infection. IMPORTANCEWith 400 million worldwide infections each year, dengue is the most common vector-born viral disease. 40% of the worlds population is at risk with dengue experiencing consistent geographic spread over the years. With no therapeutics available and vaccines performing sub optimally, the need for an effective dengue vaccine is urgent. Here we develop and characterize a novel mRNA vaccine encoding for the dengue serotype 1 envelope and premembrane structural proteins that is delivered via a lipid nanoparticle. Our DENV1 prM/E mRNA-LNP vaccine induces neutralizing antibody and cellular immune responses in immunocompetent mice and protects an immunocompromised mouse from a lethal DENV challenge. Existing antibodies against dengue can enhance subsequent infections via antibody-dependent enhancement. Importantly our vaccine only induced serotype specific immune responses and did not induce ADE.

microbiology↗