Computational peptide engineering approach for selection of the new C05 antibody-driven peptide with potency to blocking influenza a virus attachment; from in silico to in vivo

Antiviral drugs are currently used to prevent or treat viral infections like influenza A Virus (IAV). Nonetheless, annual genetic mutations of influenza viruses make them resistant to efficient treatment by current medications. Antiviral peptides have recently attracted researchers' attention and can potentially supplant the current medications. This study aimed to design peptides against IAV propagation. For this purpose, P2 and P3 peptides were computationally designed based on the HCDR3 region of the C05 antibody (a monoclonal antibody that neutralizes influenza HA protein and inhibits the virus attachment). The synthesized peptides were tested against the influenza A virus (A/Puerto Rico/8/34 (H1N1)) in vitro, and the most efficient peptide was selected for in vivo experiments. It was shown that the designed peptide shows much more prophylactic and therapeutic effects against the virus. These findings demonstrated that the designed peptide can control the virus infection without any cytotoxicity effect. Antiviral peptide design is acknowledged as a critical tactic to manage viral infections by preventing viral binding to the host cells.Communicated by Ramaswamy H. Sarma.

Fusion Protein Consisting of Hemagglutinin Small Subunit and Truncated Nucleoprotein as a Universal Influenza Vaccine Candidate: Starting In-Silico Evaluation Toward In Vitro Expression

Background

Influenza virus is a respiratory pathogen, which causes high degree of mortality and morbidity during seasonal epidemics and sporadic pandemics. By selecting conserved antigenic proteins, for example, hemagglutinin small subunit (HA2) and nucleoprotein (NP), we aimed to develop a vaccine based on a fusion protein leading to both cellular and humoral responses that are the most challenging aspects in designing a universal vaccine.

Materials and Methods

The bioinformatics analysis was performed for HA2-NP structure and function prediction. Primers for the antigenic part of NP were designed using bioinformatics tools. The desired product was amplified via polymerase chain reaction using the designed primers, which was then penetrated into T vector, followed by insertion into pET28a vector in order to construct pET28a/NP. The pET28a/HA2, previously generated in our lab, was digested with the same restriction enzymes as pET28a/NP (HindIII/Xhol). Then, NP was inserted to the downstream region of HA2 to construct pET28a/HA2.

Results

The generated pET28a/HA2-NP was transformed into Escherichia coli BL21 (DE3). The expression was induced by isopropyl β-d-l-thiogalactopyranoside. The results showed that the antigenic segment of NP was successfully cloned into pET28a/ HA2. The protein band of HA2-NP was observed on sodium dodecyl sulfate polyacrylamide gel electrophoresis, confirmed by Western blotting and purified with Ni-NTA purification system (QIAGEN, Germany).

Conclusion

As currently available vaccines can cause some allergic reactions, using a chimer protein based on the bioinformatics analysis is continual, safe, and affordable, thus stimulating both cellular and humoral immunity systems. Our construct could potentially provide a basis for a universal vaccine candidate.

The Power and Limitations of Influenza Virus Hemagglutinin Assays

Influenza virus hemagglutinins (HAs) are surface proteins that bind to sialic acid residues at the host cell surface and ensure further virus internalization. Development of methods for the inhibition of these processes drives progress in the design of new antiviral drugs. The state of the isolated HA (i.e. combining tertiary structure and extent of oligomerization) is defined by multiple factors, like the HA source and purification method, posttranslational modifications, pH, etc. The HA state affects HA functional activity and significantly impacts the results of numerous HA assays. In this review, we analyze the power and limitations of currently used HA assays regarding the state of HA.

The sweet tooth of bacteria: common themes in bacterial glycoconjugates

Humans have been increasingly recognized as being superorganisms, living in close contact with a microbiota on all their mucosal surfaces. However, most studies on the human microbiota have focused on gaining comprehensive insights into the composition of the microbiota under different health conditions (e.g., enterotypes), while there is also a need for detailed knowledge of the different molecules that mediate interactions with the host. Glycoconjugates are an interesting class of molecules for detailed studies, as they form a strain-specific barcode on the surface of bacteria, mediating specific interactions with the host. Strikingly, most glycoconjugates are synthesized by similar biosynthesis mechanisms. Bacteria can produce their major glycoconjugates by using a sequential or an en bloc mechanism, with both mechanistic options coexisting in many species for different macromolecules. In this review, these common themes are conceptualized and illustrated for all major classes of known bacterial glycoconjugates, with a special focus on the rather recently emergent field of glycosylated proteins. We describe the biosynthesis and importance of glycoconjugates in both pathogenic and beneficial bacteria and in both Gram-positive and -negative organisms. The focus lies on microorganisms important for human physiology. In addition, the potential for a better knowledge of bacterial glycoconjugates in the emerging field of glycoengineering and other perspectives is discussed.