Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused huge social and economic distress. Given its rapid spread and the lack of specific treatment options, SARS-CoV-2 needs to be inactivated according to strict biosafety measures during laboratory diagnostics and vaccine development. The inactivation method for SARS-CoV-2 affects research related to the natural virus and its immune activity as an antigen in vaccines. In this study, we used size exclusion chromatography, western blotting, ELISA, an electron microscope, dynamic light scattering, circular dichroism, and surface plasmon resonance to evaluate the effects of four different chemical inactivation methods on the physical and biochemical characterization of SARS-CoV-2. Formaldehyde and β-propiolactone (BPL) treatment can completely inactivate the virus and have no significant effects on the morphology of the virus. None of the four tested inactivation methods affected the secondary structure of the virus, including the α-helix, antiparallel β-sheet, parallel β-sheet, β-turn, and random coil. However, formaldehyde and long-term BPL treatment (48 h) resulted in decreased viral S protein content and increased viral particle aggregation, respectively. The BPL treatment for 24 h can completely inactivate SARS-CoV-2 with the maximum retention of the morphology, physical properties, and the biochemical properties of the potential antigens of the virus. In summary, we have established a characterization system for the comprehensive evaluation of virus inactivation technology, which has important guiding significance for the development of vaccines against SARS-CoV-2 variants and research on natural SARS-CoV-2.

Influenza is a potentially fatal acute respiratory viral disease caused by the influenza virus. Influenza viruses vary in antigenicity and spread rapidly, resulting in seasonal epidemics. Vaccination is the most effective strategy for lowering the incidence and fatality rates of influenza-related disorders, and it is also an important method for reducing seasonal influenza infections. Mammalian Madin–Darby canine kidney (MDCK) cell lines are recommended for influenza virus growth, and such cell lines have been utilized in several commercial influenza vaccine productions. The limit dilution approach was used to screen ATCC-MDCK cell line subcellular strains that are especially sensitive to H1N1, H3N2, BV, and BY influenza viruses to increase virus production, and research on influenza virus culture media was performed to support influenza virus vaccine development. We also used RNA sequencing to identify differentially expressed genes and a GSEA analysis to determine the biological mechanisms underlying the various levels of susceptibility of cells to influenza viruses. MDCK cell subline 2B6 can be cultured to increase titer and the production of the H1N1, H3N2, BV, and BY influenza viruses. MDCK-2B6 has a significantly enriched and activated in ECM receptor interaction, JAK-STAT signaling, and cytokine receptor interaction signaling pathways, which may result in increased cellular susceptibility and cell proliferation activity to influenza viruses, promote viral adsorption and replication, and elevate viral production, ultimately. The study revealed that MDCK-2B6 can increase the influenza virus titer and yield in vaccine production by increasing cell sensitivity and enhancing proliferative activity.

Since 2022, mpox epidemics have been sustaining and escalating over the world, posing a significant public health challenge. While significant progress has been made in diagnostic methodologies, prophylactic vaccines, and therapeutic interventions to mitigate monkeypox virus (MPXV) infection, scientific understanding of MPXV and related orthopoxviruses continues to evolve progressively. In order to keep pace with recent advancements, herein we review progress in mpox research from five key perspectives. This article first summarizes the latest epidemiological profiles, incorporating different viral lineages globally and in China, while highlighting their evolutionary history and distinct clinical characteristics. The virological profiles of MPXV shed light on its complete infectious lifecycle and the formation of distinct virus particle types. Clinically approved classical detection methods and emerging novel testing techniques are provided, establishing a framework for early diagnosis of mpox patients. The efficacy and safety of both licensed vaccines and those under development are analyzed to underscore their value in preventing mpox infection. Additionally, progress in approved and newly identified potential therapeutic agents is summarized and discussed, aiming to provide insights for further drug development and clinical treatment strategies.

The production efficiency of a cell substrate directly affects the yield of target products such as viruses, while its density is mainly regulated by the type of culture medium and culture conditions. In this study, Vero cells were used as model cells for systematic medium screening, and a high-efficiency medium for biological drug production was identified. Through the results of cell proliferation by a cell counting kit (CCK)-8 assay, 5-Ethynyl-2′-deoxyuridine(EdU) assay, real-time quantitative PCR (RT-qPCR) and Western blotting, we found that adding an appropriate amount of vitamin B to the conventional basic medium can significantly improve and maintain the high-density growth of Vero cells. In addition, the molecular mechanism of the high-density culture of Vero cells promoted by B vitamins is explained for the first time by using the systems multi-omics analysis methods. Here, we determined that B vitamins regulate cell proliferation through the synthesis and metabolism of unsaturated fatty acids, affecting the productivity of cell substrate in industrial production. This study provides an important tool for the screening of key components of cell-based high-efficiency medium.

Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in late 2019, the virus has been mutating continuously, resulting in the continuous emergence of variants and creating challenges for epidemic prevention and control. Here, we immunized mice with different vaccine candidates, revealing the immune, protein, and metabolomic changes that take place in vaccines composed of different variants. We found that the prototype strain and Delta- and Omicron-variant inactivated vaccine candidates could all induce a high level of neutralizing antibodies and cellular immunity responses in mice. Next, we found that the metabolic and protein profiles were changed, showing a positive association with immune responses, and the level of the change was distinct in different inactivated vaccines, indicating that amino acid variations could affect metabolomics and proteomics. Our findings reveal differences between vaccines at the metabolomic and proteomic levels. These insights provide a novel direction for the immune evaluation of vaccines and could be used to guide novel strategies for vaccine design.