Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia. Japanese encephalitis (JE) caused by JEV is characterized by extensive inflammatory cytokine secretion, microglia activation, blood-brain barrier (BBB) breakdown, and neuronal death, all of which contribute to the vicious cycle of inflammatory damage. There are currently no effective treatments for JE. Mesenchymal stem cells (MSCs) have been demonstrated to have a therapeutic effect on many central nervous system (CNS) diseases by regulating inflammation and other mechanisms. In vivo, 8- to 10-week-old mice were infected intraperitoneally with JEV and syngeneic bone marrow MSCs were administered through the caudal vein at 1 and 3 days post-infection. The mortality, body weight, and behavior were monitored daily. Brains from each group were harvested at the indicated times for hematoxylin and eosin staining, immunohistochemical observation, flow cytometric analysis, TUNEL staining, Western blot, quantitative real-time polymerase chain reaction, and BBB permeability assays. In vitro, co-culture and mixed culture experiments of MSCs with either microglia or neurons were performed, and then the activation state of microglia and survival rate of neurons were tested 48 h post-infection. MSC treatment reduced JEV-induced mortality and improved the recovery from JE in our mouse model. The inflammatory response, microglia activation, neuronal damage, BBB destruction, and viral load (VL) were significantly decreased in the MSC-treated group. In co-culture experiments, MSCs reprogrammed M1-to-M2 switching in microglia and improved neuron survival. Additionally, the VL was decreased in Neuro2a cells in the presence of MSCs accompanied by increased expression of interferon-α/β. MSC treatment alleviated JEV-induced inflammation and mortality in mice.

Efficient isolation of endogenously assembled viral RNA-protein complexes is essential for understanding virus replication mechanisms. We have developed an affinity purification strategy based on an RNA affinity tag that allows large-scale preparation of native viral RNA-binding proteins (RBPs). The streptavidin-binding aptamer S1 sequence was inserted into the 3′ end of dengue virus (DENV) 5′–3′ UTR RNA, and the DENV RNA UTR fused to the S1 RNA aptamer was expressed in living mammalian cells. This allowed endogenous viral ribonucleoprotein (RNP) assembly and isolation of RNPs from whole cell extract, through binding the S1 aptamer to streptavidin magnetic beads. Several novel host DENV RBPs were subsequently identified by liquid chromatography with tandem mass spectrometry (LC-MS/MS), including RPS8, which we further implicate in DENV replication. We proposed efficient S1 aptamer-based isolation of viral assembled RNPs from living mammalian cells will be generally applicable to the purification of high- and low-affinity RBPs and RNPs under endogenous conditions.

Old World orthohantaviruses , including Hantaan virus (HTNV), cause hemorrhagic fever with renal syndrome (HFRS) in Eurasia. Available inactivated vaccines often induce low neutralizing antibodies and short-term protection. We evaluated nucleic acid vaccines expressing a prefusion-stabilized HTNV glycoprotein in female BALB/c mice. Both DNA and mRNA-LNP versions elicited robust neutralizing antibodies by strongly activating germinal centers, which protected mice against high-dose HTNV challenge. We further tested heterologous prime-boost regimens, where mice primed with inactivated vaccine received different boosters. All boosters increased neutralizing titers, but only the prefusion-stabilized glycoprotein mRNA-LNP vaccine raised titers to the level achieved by its own full primary vaccination course. This demonstrates the immunogen’s superiority in developing next-generation vaccines and its unique ability to potently recall memory B cells induced by suboptimal inactivated vaccines. Thus, prefusion-stabilized glycoprotein-based nucleic acid vaccines are promising candidates for advanced orthohantavirus vaccine development.

Influenza viruses remain a major global public health concern, causing significant morbidity and mortality annually despite widespread vaccination efforts. The limitations of current seasonal vaccines, including strain-specific efficacy and manufacturing delays, have accelerated the development of next-generation candidates aiming for universal protection. This review comprehensively summarizes the recent progress in universal influenza vaccine research. We first outline the key conserved antigenic targets, such as the hemagglutinin (HA) stem, neuraminidase (NA), and matrix proteins (M2e, NP, and M1), which are crucial for eliciting broad cross-reactive immunity. We then delve into advanced antigen design strategies, including immunofocusing, multi-antigen combinations, computationally optimized broadly reactive antigens (COBRA), and nanoparticle-based platforms. Furthermore, we evaluate evolving vaccine delivery systems, from traditional inactivated and live-attenuated vaccines to modern mRNA and viral vector platforms, alongside the critical role of novel adjuvants in enhancing immune responses. The convergence of these disciplines—structural biology, computational design, and nanotechnology—is driving the field toward a transformative goal. We conclude that the successful development of a universal influenza vaccine will likely depend on the strategic integration of these innovative approaches to overcome existing immunological and logistical challenges, ultimately providing durable and broad-spectrum protection against diverse influenza virus strains.

Objective: The increase in vascular permeability and bleeding caused by systemic endothelial damage is the most basic pathological change of hemorrhagic fever with renal syndrome(HFRS) caused by Hantavirus, but there is a lack of early biomarkers to detect the severity and prognosis of HFRS. Soluble thrombomodulin (sTM) is a sensitive marker of endothelial damage. In this study we investigated the role of sTM in the evaluation of the severity and prognosis of HFRS patients. Methods: A retrospective analysis was conducted on 51 patients with HFRS treated in the Infectious Diseases Department of the Second Affiliated Hospital of Air Force Medical University from January 2023 to January 2024. We compared the changes of sTM among patients with HFRS in different phases and subtypes, and analyzed the correlation between sTM and related laboratory diagnostic indicators. Additionally, we evaluated the differences of sTM and related laboratory diagnostic indicators between survivors and non-survivors, and assessed the predictive ability of sTM for the mortality risk of HFRS patients based on the ROC curve, and determined the cut-off value of sTM. Results: In the HFRS phases, sTM increased during the febrile phase, reached its peak during the hypotensive phase, and decreased during the oliguria-dipuria phase. In the HFRS subtypes, there was no difference between the mild and moderate subtypes ( P > 0.05), while in the moderate, severe, and critical subtypes, it showed a “stepwise” increase ( P < 0.05), with the greatest jump being from “severe” to “critical” ( P < 0.0001). Linear regression analysis revealed a strong positive correlation between sTM and SOFA scores (R² = 0.6076, P < 0.0001). The level of sTM in the non-survivor group (62.25 (54.60, 81.98) TU/mL) was significantly higher than that in the survivor group (28.10 (21.40, 44.15) TU/mL). The ROC curve indicated that the AUC of sTM was 0.9317, which had a high predictive value for the mortality risk of HFRS patients and was second only to SOFA (0.9309), and the combined AUC could reach 0.9492. When the cut-off of sTM was 49.98 TU/mL, the sensitivity and specificity were 81.36% and 100%. In addition, the Kaplan-Meiers survival analysis showed that when sTM ≥ 49.8 TU/mL, the 28-day mortality rate of HFRS patients was higher ( P < 0.01). Conclusion: sTM serves as a valuable biomarker for risk stratification and prognosis evaluation in HFRS.

Objective: The hemorrhagic fever with renal syndrome (HFRS) is an acute viral infectious disease characterized by multi‐system damage involving complex mechanisms. Effective identification of critically ill patients is essential for the prognosis of HFRS. The aim of this study was to investigate the utility of the neutrophil CD64 index (nCD64 index) in predicting the severity of HFRS. Methods: This study included 64 HFRS patients from the Center for Infectious Diseases of the Second Affiliated Hospital of Air Force Medical University between October 2023 and March 2024. The expression of CD64 on neutrophils was assessed using flow cytometry, and the nCD64 index was calculated. White blood cell (WBC), Procalcitonin (PCT), C‐reactive protein (CRP), Il‐6, and creatinine levels were measured for each patient, and Sequential Organ Failure Assessment (SOFA) scores were determined. Results: The expression of nCD64 was generally elevated in HFRS patients and demonstrated a positive correlation with WBC, neutrophil, lymphocyte, monocyte, and PCT, as well as a negative correlation with platelet. The receiver operating characteristic (ROC) curve of nCD64 index for predicting high SOFA score patients outperformed those of CRP, creatinine and WBC, and was equivalent to that of IL‐6 and PCT. Conclusion: The nCD64 index has the potential to serve as an effective biomarker for monitoring disease progression and assessing treatment efficacy in HFRS.