Protective CD8+ T-cell response against Hantaan virus infection induced by immunization with designed linear multi-epitope peptides in HLA-A2.1/Kb transgenic mice

Integrating immunoinformatics and computational epitope prediction for a vaccine candidate against respiratory syncytial virus

Respiratory syncytial virus (RSV) poses a significant global health threat, especially affecting infants and the elderly. Addressing this, the present study proposes an innovative approach to vaccine design, utilizing immunoinformatics and computational strategies. We analyzed RSV's structural proteins across both subtypes A and B, identifying potential helper T lymphocyte, cytotoxic T lymphocyte, and linear B lymphocyte epitopes. Criteria such as antigenicity, allergenicity, toxicity, and cytokine-inducing potential were rigorously examined. Additionally, we evaluated the conservancy of these epitopes and their population coverage across various RSV strains. The comprehensive analysis identified six major histocompatibility complex class I (MHC-I) binding, five MHC-II binding, and three B-cell epitopes. These were integrated with suitable linkers and adjuvants to form the vaccine. Further, molecular docking and molecular dynamics simulations demonstrated stable interactions between the vaccine candidate and human Toll-like receptors (TLR4 and TLR5), with a notable preference for TLR4. Immune simulation analysis underscored the vaccine's potential to elicit a strong immune response. This study presents a promising RSV vaccine candidate and offers theoretical support, marking a significant advancement in vaccine development efforts. However, the promising in silico findings need to be further validated through additional in vivo studies.

Vaccination-Route-Dependent Adjuvanticity of Antigen-Carrying Nanoparticles for Enhanced Vaccine Efficacy

Vaccination-route-dependent adjuvanticity was identified as being associated with the specific features of antigen-carrying nanoparticles (NPs) in the present work. Here, we demonstrated that the mechanical properties and the decomposability of NP adjuvants play key roles in determining the antigen accessibility and thus the overall vaccine efficacy in the immune system when different vaccination routes were employed. We showed that soft nano-vaccines were associated with more efficient antigen uptake when administering subcutaneous (S.C.) vaccination, while the slow decomposition of hard nano-vaccines promoted antigen uptake when intravenous (I.V.) vaccination was employed. In comparison to the clinically used aluminum (Alum) adjuvant, the NP adjuvants were found to stimulate both humoral and cellular immune responses efficiently, irrespective of the vaccination route. For vaccination via S.C. and I.V. alike, the NP-based vaccines show excellent protection for mice from Staphylococcus aureus (S. aureus) infection, and their survival rates are 100% after lethal challenge, being much superior to the clinically used Alum adjuvant.

Advances and perspectives in the development of vaccines against highly pathogenic bunyaviruses

Increased human activities around the globe and the rapid development of once rural regions have increased the probability of contact between humans and wild animals. A majority of bunyaviruses are of zoonotic origin, and outbreaks may result in the substantial loss of lives, economy contraction, and social instability. Many bunyaviruses require manipulation in the highest levels of biocontainment, such as Biosafety Level 4 (BSL-4) laboratories, and the scarcity of this resource has limited the development speed of vaccines for these pathogens. Meanwhile, new technologies have been created, and used to innovate vaccines, like the mRNA vaccine platform and bioinformatics-based antigen design. Here, we summarize current vaccine developments for three different bunyaviruses requiring work in the highest levels of biocontainment: Crimean-Congo Hemorrhagic Fever Virus (CCHFV), Rift Valley Fever Virus (RVFV), and Hantaan virus (HTNV), and provide perspectives and potential future directions that can be further explored to advance specific vaccines for humans and livestock.

Correlation analysis of CD8+ cell overexpression and prognosis of hemorrhagic fever with renal syndrome-a case-control study

Background

Hemorrhagic fever with Renal Syndrome (HFRS) is an infectious disease caused by Hantavirus with fever, hemorrhage and acute kidney injury (AKI) as clinical characteristics. The research on the etiology and pathogenesis of diseases has become a focus of attention. However, there are few related medical studies in children with HFRS. The prognosis of the children with HFRS remains to be explored.

Objectives

We explored risk factors in children with HFRS and summarize sensitive indicators that are conducive to the prognosis of the disease.

Methods

We designed a case-control study and recruited 182 HFRS pediatric patients (2014.01-2022.08). They were divided into two groups according to the severity of disease, including the control group(158 cases with mild and moderate subgroup)and the observation group (24 cases with severe and critical subgroup). Risk factors influencing prognosis were analyzed by binary logistic regression. The cutoff value, sensitivity and specificity of the risk factors prediction were calculated by receiver operating characteristic (ROC) and Yoden index.

Results

Lymphocyte subsets characteristics analysis showed that in observation group the indexes were decreased in lymphocyte, T lymphocytes (CD3)⁺, helper/inducible T lymphocytes (CD4⁺)/inhibition/cytotoxic T cells (CD8⁺), B lymphocytes (CD19⁺); and the elevated index was CD8⁺, the difference were all significant between two groups. (P < 0.05). With death as the primary outcome, it was found that the serum CD8⁺ (odds ratio [OR] 2.91, 95% confidence interval [CI] 1.65, 4.00; P < 0.01) was risk factor and significantly associated with mortality. The cutoff value of the serum CD8⁺ was 845 × 10⁶/L, the sensitivity and specificity were 78.5%, 85.4%. With complications as the secondary outcomes, the serum CD8⁺ (OR 2.69, 95% CI 1.15, 4.88; P < 0.01) was found to be risk factors. The cutoff of the serum CD8⁺ was 690 × 10⁶/L, the sensitivity and specificity were 69.3%, 75.1% respectively.

Conclusion

CD8⁺ may be significantly correlated with the severity and prognosis of HFRS in children.

IL-15 induced bystander activation of CD8+ T cells may mediate endothelium injury through NKG2D in Hantaan virus infection

Introduction

Hantaan virus (HTNV) can cause endothelium injury in hemorrhagic fever with renal syndrome (HFRS) patients. Bystander activation of CD8+ T cells by virus infection has been shown that was involved in host injury, but it is unclear during HTNV infection. This project aimed to study the effect of bystander-activated CD8+ T cell responses in HTNV infection.

Methods

The in vitro infection model was established to imitate the injury of endothelium in HFRS patients. Flow cytometry was performed to detect the expression of markers of tetramer+ CD8+ T cells and human umbilical vein endothelial cells (HUVECs). The levels of interleukin-15 (IL-15) in serum and supermanant were detected using ELISA kit. The expression of MICA of HUVECs was respectively determined by flow cytometry and western blot. The cytotoxicity of CD8+ T cells was assessed through the cytotoxicity assay and antibody blocking assay.

Results

EBV or CMV-specific CD8+ T cells were bystander activated after HTNV infection in HFRS patients. HTNV-infected HUVECs in vitro could produce high levels of IL-15, which was positively correlated with disease severity and the expression of NKG2D on bystander-activated CD8+ T cells. Moreover, the elevated IL-15 could induce activation of CD122 (IL-15Rβ)+NKG2D+ EBV/CMV-specific CD8+ T cells. The expression of IL-15Rα and ligand for NKG2D were upregulated on HTNV-infected HUVECs. Bystander-activated CD8+ T cells could exert cytotoxicity effects against HTNV-infected HUVECs, which could be enhanced by IL-15 stimulation and blocked by NKG2D antibody.

Discussion

IL-15 induced bystander activation of CD8+ T cells through NKG2D, which may mediate endothelium injury during HTNV infection in HFRS patients.

Comparative Immunoreactivity Analyses of Hantaan Virus Glycoprotein-Derived MHC-I Epitopes in Vaccination

MHC-I antigen processes and presentation trigger host-specific anti-viral cellular responses during infection, in which epitope-recognizing cytotoxic T lymphocytes eliminate infected cells and contribute to viral clearance through a cytolytic killing effect. In this study, Hantaan virus (HTNV) GP-derived 9-mer dominant epitopes were obtained with high affinity to major HLA-I and H-2 superfamilies. Further immunogenicity and conservation analyses selected 11 promising candidates, and molecule docking (MD) was then simulated with the corresponding MHC-I alleles. Two-way hierarchical clustering revealed the interactions between GP peptides and MHC-I haplotypes. Briefly, epitope hotspots sharing good affinity to a wide spectrum of MHC-I molecules highlighted the biomedical practice for vaccination, and haplotype clusters represented the similarities among individuals during T-cell response establishment. Cross-validation proved the patterns observed through both MD simulation and public data integration. Lastly, 148 HTNV variants yielded six types of major amino acid residue replacements involving four in nine hotspots, which minimally influenced the general potential of MHC-I superfamily presentation. Altogether, our work comprehensively evaluates the pan-MHC-I immunoreactivity of HTNV GP through a state-of-the-art workflow in light of comparative immunology, acknowledges present discoveries, and offers guidance for ongoing HTNV vaccine pursuit.

Deciphering the immunogenic T-cell epitopes from spike protein of SARS-CoV-2 concerning the diverse population of India

Scientists are rigorously looking for an efficient vaccine against the current pandemic due to the SARS-CoV-2 virus. The reverse vaccinology approach may provide us with significant therapeutic leads in this direction and further determination of T-cell/B-cell response to antigen. In the present study, we conducted a population coverage analysis referring to the diverse Indian population. From the Immune epitope database (IEDB), HLA- distribution analysis was performed to find the most promiscuous T-cell epitope out of In silico determined epitope of Spike protein from SARS-CoV-2. Epitopes were selected based on their binding affinity with the maximum number of HLA alleles belonging to the highest population coverage rate values for the chosen geographical area in India. 404 cleavage sites within the 1288 amino acids sequence of spike glycoprotein were determined by NetChop proteasomal cleavage prediction suggesting the presence of adequate sites in the protein sequence for cleaving into appropriate epitopes. For population coverage analysis, 179 selected epitopes present the projected population coverage up to 97.45% with 56.16 average hit and 15.07 pc90. 54 epitopes are found with the highest coverage among the Indian population and highly conserved within the given spike RBD domain sequence. Among all the predicted epitopes, 9-mer TRFASVYAW and RFDNPVLPF along with 12-mer LLAGTITSGWTF and VSQPFLMDLEGK epitopes are observed as the best due to their decent docking score and best binding affinity to corresponding HLA alleles during MD simulations. Outcomes from this study could be critical to design a vaccine against SARS-CoV-2 for a different set of populations within the country.Communicated by Ramaswamy H. Sarma.

Immunogenic Properties of MVs Containing Structural Hantaviral Proteins: An Original Study

Hemorrhagic fever with renal syndrome (HFRS) is an emerging infectious disease that remains a global public health threat. The highest incidence rate is among zoonotic disease cases in Russia. Most cases of HFRS are reported in the Volga region of Russia, which commonly identifies the Puumala virus (PUUV) as a pathogen. HFRS management is especially challenging due to the lack of specific treatments and vaccines. This study aims to develop new approaches for HFRS prevention. Our goal is to test the efficacy of microvesicles (MVs) as PUUV nucleocapsid (N) and glycoproteins (Gn/Gc) delivery vehicles. Our findings show that MVs could deliver the PUUV N and Gn/Gc proteins in vitro. We have also demonstrated that MVs loaded with PUUV proteins could elicit a specific humoral and cellular immune response in vivo. These data suggest that an MV-based vaccine could control HFRS.