During the Coronavirus disease 2019 (COVID-19) pandemic, vaccination against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has proven to be an important measure to help control disease spread and improve patient outcome. There are four distinct vaccine categories: inactivated viral vaccines, messenger RNA (mRNA) vaccines, adenovirus vector-based vaccines, and adjuvanted protein vaccines. In 2021, increased cases of myocarditis and pericarditis were reported after mRNA and adenovirus vector-based COVID-19 vaccination. A similar reporting pattern has not been observed after receipt of inactivated virus vaccines. Here, we present a case of clinically suspected acute myocarditis in a 26-year-old female, occurring 11 days after the administration of Sinopharm Vero Cell, an inactivated virus COVID-19 vaccine. This event led to acute heart failure, with marked clinical resolution observed within 34 days.

Coxiella burnetii is the bacterial causative agent of the zoonosis Q fever. This bacterium undergoes lipopolysaccharide (LPS) phase transition similar to Enterobacteriaciae upon in vitro passage. Full-length, phase I C. burnetii LPS is a critical virulence factor and profoundly impacts vaccine-induced immunogenicity; thus, LPS phase is an important consideration in C. burnetii experimentation and Q fever vaccine design. Typically, phase I LPS-expressing organisms are obtained from the tissues of infected experimental animals. In this process, residual phase II LPS-expressing organisms are thought to be cleared by the host immune system. Here, we propose an efficient and non-animal-based method for the enrichment of C. burnetii phase I LPS-expressing bacteria in vitro. We utilize both Vero cell culture to selectively enrich solutions with phase I and intermediate phase LPS-expressing bacteria. This simple and quick method decreases reliance on experimental animals and is a sustainable solution for Q fever diagnostic and vaccine development hurdles.

Despite ongoing control efforts, the mosquito population and diseases vectored by them continue to thrive worldwide, causing major health concerns. There has been growing interest in the use of botanicals as alternatives to insecticides due to their widespread insecticidal properties, biodegradability, and adaptability to ecological conditions. In this study, we investigated the larvicidal activity and cytotoxicity effects of solvent extracts from three aromatic plants-Curcuma longa (turmeric), Ocimum americanum (hoary basil), and Petroselinum crispum (parsley)-against Aedes albopictus. Subsequently, we examined the phytochemical composition of the extracts through gas chromatography-mass spectrometry (GC-MS) analysis. Results revealed that the hexane extracts of O. americanum and P. crispum exhibited the greatest larvicidal activity with the lowest median lethal concentration (LC50) values (<30 µg/mL) at 24 h post-treatment, with the former found to be significantly less toxic towards African monkey kidney (Vero) cells. The GC-MS analysis of the said extract indicated the presence of different classes of metabolites, including phenylpropanoids, very long-chain alkanes, fatty acids and their derivatives, and terpenes, with the most abundant component being methyl eugenol (55.28%), most of which, have been documented for their larvicidal activities. These findings provide valuable insights into the potential use and development of bioinsecticides, particularly from O. americanum.

Toxoplasmosis is a zoonotic disease that infects most animals, including humans. Pyrimethamine/sulfadiazine is the standard treatment for toxoplasmosis. Although this treatment has been successful, it is often associated with side effects that cannot be tolerated. Therefore, various compounds have been proposed as alternative treatments for toxoplasmosis. Antimicrobial peptides (AMPs) act on various pathogens, from viruses to protozoa. The purpose of the present study was to evaluate the effects of CM11 on in vitro and in vivo Toxoplasma gondii infection. For in vitro experiments, VERO cells were treated with different concentrations of CM11 (1-128 μg/ml) compared to sulfadiazine (SDZ) (0.78-100 μg/ml). MTT and lactate dehydrogenase (LDH) assays evaluated the cell viability and plasma membrane integrity. Then, the inhibitory concentration (IC50) values were determined for treating tachyzoites of T. gondii before or on cells previously infected. Annexin V-FITC/propidium iodide (PI) staining was used to distinguish viable and apoptotic cells. The effect of CM11, SDZ, and a combination of CM11 and SDZ was evaluated in the BALB/c mouse model of acute toxoplasmosis. CM11 was effective on tachyzoites of T. gondii and had a time and dose-dependent manner. The results of the MTT assay showed that the CC50 values of CM11 and SDZ were estimated at 17.4 µg/ml and 62.3 µg/ml after 24-h, respectively. The inhibitory concentration (IC50) of CM11 and SDZ on infected cells was estimated at 1.9 µg/ml and 1.4 µg/ml after 24-h, respectively. The highest rate of apoptosis (early and late) in high concentrations of SDZ and CM11 was determined for tachyzoites (2.13 % and 13.88 %), non-infected VERO cells (6.1 % and 19.76 %), and infected VERO cells (7.45 % and 29.9 %), respectively. Treating infected mice with CM11 and a combination of CM11 and SDZ had increased survival time. Based on the mentioned results, it can be concluded that CM11 has a beneficial effect on tachyzoites of T. gondii in vitro. The result of the mouse model suggests that CM11, either alone or in combination with other chemotherapeutic agents, could be a potential therapeutic for toxoplasmosis. Hence, antimicrobial peptides could be applied as promising anti-toxoplasma agents for treating toxoplasmosis.

Post-vaccination adverse reactions have been reported with varying symptoms and severity owing to research and production time pressures during the coronavirus disease 2019 (COVID-19) pandemic. In this article, we report a rare case of Guillain-Barré syndrome (GBS) in a patient with COVID-19 with acute respiratory distress syndrome (ARDS) after receiving Sinopharm\'s Vero Cell vaccine (China). The patient who was initially negative for COVID-19 was diagnosed with GBS based on paralysis that developed from the lower extremities to the upper extremities, as confirmed by cytoalbuminologic dissociation in the cerebrospinal fluid. The patient\'s condition worsened with ARDS caused by COVID-19 infection during the hospital stay, and SpO2 decreased to 83% while receiving oxygen through a non-rebreather mask (15 l/min) on day 6. The patient was treated with standard therapy for severe COVID-19, invasive mechanical ventilation, and five cycles of therapeutic plasma exchange (TPE) with 5% albumin replacement on day 11 due to severe progression. The patient was weaned off the ventilator on day 28, discharged on day 42, and was completely healthy after 6 months without any neurological sequelae until now. Our report showed the potential of TPE for GBS treatment in critically ill patients with COVID-19 after COVID-19 vaccination.

Infectious bronchitis virus (IBV) has restricted cell and tissue tropism. IBVs, except the Beaudette strain, can infect and replicate in chicken embryos, primary chicken embryo kidneys, and primary chicken kidney cells, only. The limited viral cell tropism of IBV substantially hinders in vitro cell-based research on pathogenic mechanisms and vaccine development. Herein, the parental H120 vaccine strain was serially passaged for five generations in chicken embryos, 20 passages in CK cells and 80 passages in Vero cells. This passaging yielded a Vero cell-adapted strain designated HV80. To further understand viral evolution, serial assessments of infection, replication, and transmission in Vero cells were performed for the viruses obtained every tenth passage. The ability to form syncytia and the replication efficiency significantly after the 50th passage (strain HV50). HV80 also displayed tropism extension to DF-1, BHK-21, HEK-293 T, and HeLa cells. Whole genome sequencing of viruses from every tenth generation revealed a total of 19 amino acid point mutations in the viral genome by passage 80, nine of which occurred in the S gene. The second furin cleavage site appeared in viral evolution and may be associated with cell tropism extension of HV80.

An electrochemical protocol was designed to enable Vero cells to transfer electrons to an electrode without any added redox mediator. The cells were cultured on the surface of electrodes polarized at the optimal potential of 400 mV/silver pseudo-reference. Gold, carbon, and CNT-coated carbon electrodes displayed similar current record patterns. Extracellular electron transfer was sustained for several days. Its intensity, up to 1.5 pA.cell-1, was in the range of the electron flows implemented by cell respiration. A large fraction of the current vanished as soon as anoxic conditions were established, which suggests a mitochondrial origin for a large proportion of the electrons. The current records always showed a two-phase pattern. The occurrence of the two phases was not due to an evolution of the cell mat structure, which was fully established during the first day of polarization and did not change significantly thereafter. Increasing the cell seeding density decreased the maximum current reached during the first phase and the duration of the phase. These observations put together lead us to propose a model, in which only the cells adhered on the electrode surface produced current by metabolizing glutamine during the first phase. The possible role of this extracellular electron transfer as an alternative cell respiration pathway is discussed. The key roles it could play in regulating pH and pO2 gradients are considered, specifically to explain the pH gradient reversal observed in cancer cells. These pioneering results pave the way for electrochemical sensors to directly address cellular metabolic pathways.

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.

Human rhinoviruses (HRVs) are small non-enveloped RNA viruses that belong to the Enterovirus genus within the Picornaviridae family and are known for causing the common cold. Though symptoms are generally mild in healthy individuals, the economic burden associated with HRV infection is significant. A vaccine could prevent disease. The Vero-cell-based viral vaccine platform technology was considered for such vaccine development. Unfortunately, most HRV strains are unable to propagate on Vero cells due to a lack of the major receptor of HRV group A and B, intercellular adhesion molecule (ICAM1, also known as CD54). Therefore, stable human ICAM1 expressing Vero cell clones were generated by transfecting the ICAM1 gene in Vero cells and selecting clones that overexpressed ICAM1 on the cell surface. Cell banks were made and expression of ICAM1 was stable for at least 30 passages. The Vero_ICAM1 cells and parental Vero cells were infected with four HRV prototypes, B14, A16, B37 and A57. Replication of all four viruses was detected in Vero_ICAM1, but not in the parental Vero cells. Altogether, Vero cells expressing ICAM1 could efficiently propagate the tested HRV strains. Therefore, ICAM1-expressing cells could be a useful tool for the development and future production of polyvalent HRV vaccines or other viruses that use ICAM1 as a receptor.

Suid herpesvirus 1 (SuHV-1), known as pseudorabies virus (PRV), is one of the most devastating swine pathogens in China, particularly the sudden occurrence of PRV variants in 2011. The higher pathogenicity and cross-species transmission potential of the newly emerged variants caused not only colossal economic losses, but also threatened public health. To uncover the underlying pathogenesis of PRV variants, Tandem Mass Tag (TMT)-based proteomic analysis was performed to quantitatively screen the differentially expressed cellular proteins in PRV-infected Vero cells. A total of 7072 proteins were identified and 960 proteins were significantly regulated: specifically 89 upregulated and 871 downregulated. To make it more credible, the expression of XRCC5 and XRCC6 was verified by western blot and RT-qPCR, and the results dovetailed with the proteomic data. The differentially expressed proteins were involved in various biological processes and signaling pathways, such as chaperonin-containing T-complex, NIK/NF-κB signaling pathway, DNA damage response, and negative regulation of G2/M transition of mitotic cell cycle. Taken together, our data holistically outline the interactions between PRV and host cells, and our results may shed light on the pathogenesis of PRV variants and provide clues for pseudorabies prevention.