Design and Immunoinformatic Assessment of Candidate Multivariant mRNA Vaccine Construct against Immune Escape Variants of SARS-CoV-2

Revisiting the dimensions of universal vaccine with special focus on COVID-19: Efficacy versus methods of designing

Even though the use of SARS-CoV-2 vaccines during the COVID-19 pandemic showed unprecedented success in a short time, it also exposed a flaw in the current vaccine design strategy to offer broad protection against emerging variants of concern. However, developing broad-spectrum vaccines is still a challenge for immunologists. The development of universal vaccines against emerging pathogens and their variants appears to be a practical solution to mitigate the economic and physical effects of the pandemic on society. Very few reports are available to explain the basic concept of universal vaccine design and development. This review provides an overview of the innate and adaptive immune responses generated against vaccination and essential insight into immune mechanisms helpful in designing universal vaccines targeting influenza viruses and coronaviruses. In addition, the characteristics, safety, and factors affecting the efficacy of universal vaccines have been discussed. Furthermore, several advancements in methods worthy of designing universal vaccines are described, including chimeric immunogens, heterologous prime-boost vaccines, reverse vaccinology, structure-based antigen design, pan-reactive antibody vaccines, conserved neutralizing epitope-based vaccines, mosaic nanoparticle-based vaccines, etc. In addition to the several advantages, significant potential constraints, such as defocusing the immune response and subdominance, are also discussed.

Integrated structural proteomics and machine learning-guided mapping of a highly protective precision vaccine against mycoplasma pulmonis

Mycoplasma pulmonis (M. pulmonis) is an emerging respiratory infection commonly linked to prostate cancer, and it is classified under the group of mycoplasmas. Improved management of mycoplasma infections is essential due to the frequent ineffectiveness of current antibiotic treatments in completely eliminating these pathogens from the host. The objective of this study is to design and construct effective and protective vaccines guided by structural proteomics and machine learning algorithms to provide protection against the M. pulmonis infection. Through a thorough examination of the entire proteome of M. pulmonis, four specific targets Membrane protein P80, Lipoprotein, Uncharacterized protein and GGDEF domain-containing protein have been identified as appropriate for designing a vaccine. The proteins underwent mapping of cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL) (IFN)-γ ±, and B-cell epitopes using artificial and recurrent neural networks. The design involved the creation of mRNA and peptide-based vaccine, which consisted of 8 CTL epitopes associated by GGS linkers, 7 HTL (IFN-positive) epitopes, and 8 B-cell epitopes joined by GPGPG linkers. The vaccine designed exhibit antigenic behavior, non-allergenic qualities, and exceptional physicochemical attributes. Structural modeling revealed that correct folding is crucial for optimal functioning. The coupling of the MEVC and Toll-like Receptors (TLR)1, TLR2, and TLR6 was examined through molecular docking experiments. This was followed by molecular simulation investigations, which included binding free energy estimations. The results indicated that the dynamics of the interaction were stable, and the binding was strong. In silico cloning and optimization analysis revealed an optimized sequence with a GC content of 49.776 % and a CAI of 0.982. The immunological simulation results showed strong immune responses, with elevated levels of active and plasma B-cells, regulatory T-cells, HTL, and CTL in both IgM+IgG and secondary immune responses. The antigen was completely cleared by the 50th day. This study lays the foundation for creating a potent and secure vaccine candidate to combat the newly identified M. pulmonis infection in people.

Advances of Reverse Vaccinology for mRNA Vaccine Design against SARS-CoV-2: A Review of Methods and Tools

mRNA vaccines are a new class of vaccine that can induce potent and specific immune responses against various pathogens. However, the design of mRNA vaccines requires the identification and optimization of suitable antigens, which can be challenging and time consuming. Reverse vaccinology is a computational approach that can accelerate the discovery and development of mRNA vaccines by using genomic and proteomic data of the target pathogen. In this article, we review the advances of reverse vaccinology for mRNA vaccine design against SARS-CoV-2, the causative agent of COVID-19. We describe the steps of reverse vaccinology and compare the in silico tools used by different studies to design mRNA vaccines against SARS-CoV-2. We also discuss the challenges and limitations of reverse vaccinology and suggest future directions for its improvement. We conclude that reverse vaccinology is a promising and powerful approach to designing mRNA vaccines against SARS-CoV-2 and other emerging pathogens.

Design and in silico analysis of mRNA vaccine construct against Salmonella

Salmonella infections are continuously growing. Causative serovars have gained enhanced drug resistance and virulence. Current vaccines have fallen short of providing sufficient protection. mRNA vaccines have come up with huge success against SARS-CoV-2; Pfizer-BioNTech and Moderna vaccines have resulted in >90% efficacy with efficient translocation, expression, and presentation of antigen to the host immune system. Herein, based on the same approach a mRNA vaccine construct has been designed and analyzed against Salmonella by joining regions of genes of outer membrane proteins C and F of S. Typhi through a flexible linker. Construct was flanked by regulatory regions that have previously shown better expression and translocation of encoded protein. GC content of the construct was improved to attain structural and thermodynamic stability and smooth translation. Sites of strong binding miRNAs were removed through codon optimization. Protein encoded by this construct is structurally plausible, highly antigenic, non-allergen to humans, and does not cross-react to the human proteome. It is enriched in potent, highly antigenic, and conserved linear and conformational epitopes. Most conserved conformational epitopes of core protein lie on extended beta hairpins exposed to the cellular exterior. Stability and thermodynamic attributes of the final construct were found highly comparable to the Pfizer-BioNTech vaccine construct. Both contain a stable stem-loop structure downstream of the start codon and do not offer destabilizing secondary structures upstream of the start codon. Given structural and thermodynamic stability, effective immune response, and epitope composition the construct is expected to provide broad-spectrum protection against clinically important Salmonella serovars.Communicated by Ramaswamy H. Sarma.

Recombinant Hemagglutinin protein and DNA-RNA-combined nucleic acid vaccines harbored by Yeast elicit protective immunity against H9N2 Avian Influenza infection

A safe, convenience, and effective vaccine for controlling avian influenza virus infection is crucial in scale poultry production. Yeasts are considered useful vaccine vehicles for the delivery of antigens, which has been used to protect human and animal health. We report here the development of H9N2 strain hemagglutinin (HA)-based recombinant protein vaccines (rH9HA) and DNA-RNA-combined vaccine (rH9-DNA-RNA) in Saccharomyces cerevisiae for the first time. The immunogenicity assay indicated that both rH9HA and rH9-DNA-RNA could induce robust production of serum IgG, mucosal sIgA, and cellular immune responses. The reshape and diversification of gut microbiota and an enriched Lactobacillus, Debaryomyces were observed after oral immunization with rH9HA or rH9-DNA-RNA yeast vaccine, which might contribute to modulate the intestinal mucosal immunity and antiviral process. Oral immunized birds with either rH9HA or rH9-DNA-RNA were effectively protected from H9N2 virus challenge. Our findings suggested that yeast-derived H9N2 HA-based recombinant protein vaccines and DNA-RNA-combined nucleic acid vaccines are feasible and efficacious, opening up a new avenue for rapid and cost-effective production of avian influenza vaccines to achieve good protection effect.