Immunoinformatics-Based Identification of the Conserved Immunogenic Peptides Targeting of Zika Virus Precursor Membrane Protein

Computational insights in design of Crimean-Congo hemorrhagic fever virus conserved immunogenic nucleoprotein peptides containing multiple epitopes

Crimean-Congo hemorrhagic fever virus (CCHFV) belongs to Nairoviridae family and has tripartite RNA genome. It is endemic in various countries of Asia, Africa, and Europe and is primarily transmitted by Hyalomma ticks but nosocomial transmission also been reported. Vaccines for CCHF are in early phase of clinical trial; therefore, this work is centered on identification of potential immunogenic peptide as vaccine candidates with application of different immunoinformatics approaches. Eleven conserved (>90%) peptides of CCHFV nucleoprotein were selected for CD8+ T-cell (NetMHCpan 4.1b and NetCTLpan 1.1 server) and CD4+ T-cell (NetMHCIIpan-4.0 server and Tepitool) epitope prediction. Three peptides containing multiple CD8+ and CD4+ T-cell and B-cell epitopes were identified on basis of consensus prediction approach. Peptides displayed good antigenicity score of 0.45-0.68 and predicted to bind with diverse human leukocyte antigen (HLA) alleles. Molecular docking was performed with epitopes to HLA and HLA-epitopes complex to T-cell receptor (TCR). In most of the cases, docked complex of HLA-epitope and HLA-epitopes-TCR have the binding energy close to respective natural bound peptide complex with HLA and TCR. Molecular dynamic simulation also revealed that HLA-peptide complexes have minimum fluctuation and deviation than HLA-peptide-TCR docked over 50 ns simulation run. Considering these findings, identified peptides can serve as potential vaccine candidates for CCHFV disease.

Designing a Conserved Immunogenic Peptide Construct from the Nucleocapsid Protein of Puumala orthohantavirus

Puumala orthohantavirus (PUUV) is an emerging zoonotic virus endemic to Europe and Russia that causes nephropathia epidemica, a mild form of hemorrhagic fever with renal syndrome (HFRS). There are limited options for treatment and diagnosis of orthohantavirus infection, making the search for potential immunogenic candidates crucial. In the present work, various bioinformatics tools were employed to design conserved immunogenic peptides containing multiple epitopes of PUUV nucleocapsid protein. Eleven conserved peptides (90% conservancy) of the PUUV nucleocapsid protein were identified. Three conserved peptides containing multiple T and B cell epitopes were selected using a consensus epitope prediction algorithm. Molecular docking using the HPEP dock server demonstrated strong binding interactions between the epitopes and HLA molecules (ten alleles for each class I and II HLA). Moreover, an analysis of population coverage using the IEDB database revealed that the identified peptides have over 90% average population coverage across six continents. Molecular docking and simulation analysis reveal a stable interaction with peptide constructs of chosen immunogenic peptides and Toll-like receptor-4. These computational analyses demonstrate selected peptides' immunogenic potential, which needs to be validated in different experimental systems.

Zika virus precursor membrane peptides induce immune response in peripheral blood mononuclear cells

Zika virus is a re-merging flavivirus allied to serious mental health conditions in the fetuses. There is currently no preventives or treatment available for Zika infection. In this work, we have extended the in silico analysis by performing the molecular docking of previous reported three conserved Zika virus precursor membrane (prM) peptides (MP1, MP2 and MP3) with HLA complex (pHLA) and T cell receptors (TCR) and also evaluated the peptide specific immune response in human peripheral blood mononuclear cells (PBMC). Most of the CD8+ and CD4+ T cell peptides-HLA complexes demonstrated good binding energies (ΔG) and HADDOCK scores in molecular docking analysis. Immunogenic response of peptides is measured as human peripheral blood mononuclear cell (PBMC) proliferation and interferon-gamma (IFN-γ) production using a 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and a sandwich enzyme-linked immunosorbent assay (ELISA) respectively on ten different healthy blood samples. Peptide MP3 exhibited significant results in eight (cell proliferation) and seven (IFN-γ secretion) healthy volunteers' blood samples out of ten. Additionally, peptides MP1 and MP2 presented significant cell proliferation and IFN-γ release in six healthy blood samples. Thus, the outcomes from in silico and in vitro studies showed the immunogenic potential of peptides which need to validated in different experimental system before considering as candidate vaccine against Zika virus infection.