CD4+/CD8+ T lymphocytes imbalance in children with severe 2009 pandemic influenza A (H1N1) pneumonia

Review of the potential pharmacological role of erucic acid: a monounsaturated omega-9 fatty acid

This comprehensive review aims to provide an overview of the pharmacological properties of erucic acid (EA) and highlight areas that require further research. EA is an omega-9 fatty acid found in certain vegetable oil, such as rapeseed oil has demonstrated favourable effects in rodents, including ameliorating myocardial lipidosis (fat accumulation in the heart muscle), congestive heart disease, hepatic steatosis (fat accumulation in the liver), and memory impairments. These findings have prompted regulatory bodies to establish limits on EA content in food oils. The studies were performed on rodents and led to caution on ingesting the EA at high levels. Moreover, EA is frequently utilized as a nutritional supplement for the treatment of adrenoleukodystrophy, myocardial disease, and memory improvement. The review of the article indicated that EA improves cognitive function, has a part in Huntington's disease, interacts with peroxisome proliferator-activated receptors, inhibits elastase and thrombin, has anti-inflammatory, antioxidant, and anti-tumour properties, and inhibits influenza A virus. This article elucidates the pharmacological effects of EA, an omega-9 fatty acid.

Analysis of clinical characteristics and risk factors for death due to severe influenza in children

OBJECTIVE

The study analyzed the clinical features of children who had severe influenza and discussed on the risk factors associated with death in this population.

METHODS

A total of 167 children with severe influenza admitted to the intensive care unit of our hospital from January 2018 to August 2023 were selected and divided into the death group (27 cases) and the survival group (140 cases). Demographic characteristics and clinical data were collected and compared between the two groups. Logistic regression analysis was used to explore the risk factors for death in children with severe influenza.

RESULTS

The male-to-female ratio of the 167 children with severe influenza was 2.21:1, the median age was 3 years, and influenza A accounted for 70.66%. The CD4+ T cells percentage and CD4/CD8 were lower in the death group; the percentage of comorbid underlying diseases, mechanical ventilation, other systemic involvement, comorbid associated encephalopathy or encephalitis, and red blood cell distribution width (RDW), lactate dehydrogenase, activated partial thromboplastin time (APTT), and interleukin 6 were higher in the death group. The mechanical ventilation, associated encephalopathy or encephalitis, RDW, APTT, and CD4/CD8 were the independent risk factors for death.

CONCLUSION

Mechanical ventilation, comorbid encephalopathy or encephalitis, increased RDW, prolonged APTT, and decreased CD4/CD8 are independent risk factors for death in children with severe influenza.

Exploration of the mechanisms of Callicarpa nudiflora Hook. et Arn against influenza A virus (H1N1) infection

BACKGROUND

In our preliminary research on screening traditional Chinese medicine extracts for anti-H1N1 activity, we discovered that the 75 % ethanol extract of Callicarpa nudiflora Hook. & Arn (C. nudiflora) exhibited promising anti-H1N1 infection activity. However, the underlying active components and mechanism of action remain to be elucidated.

AIM OF THE STUDY

This experiment further explores the potential active components and mechanisms of action of C. nudiflora against H1N1.

METHODS

In this study, the composition of the C. nudiflora was determined using UPLC-Q-Orbitrap-MS/MS. The inhibitory effect of C. nudiflora on H1N1 was investigated using a Madin-Darby canine kidney (MDCK) cell model infected with H1N1, and the protective effect of C. nudiflora on H1N1-infected mice was examined using a Balb/c mouse model infected with H1N1. The potential mechanisms of action were demonstrated at the mRNA and protein levels.

RESULTS

A total of 21 compounds were detected in C. nudiflora, which was found to act on the replication stages of H1N1. Moreover, C. nudiflora improved the survival rate of H1N1-infected mice, enhanced the organ index, alleviated the trend of weight loss, reduced lung viral load, mitigated lung tissue damage, and regulated CD4/CD8 and Th1/Th2 immune balance. Molecular mechanism studies revealed that C. nudiflora can regulate the expression of key genes in the toll-like receptor and STAT signaling pathway.

CONCLUSION

C. nudiflora can inhibit H1N1 replication. It also can exert a regulatory effect on the immune response of H1N1-infected mice, and mitigate inflammatory damage by modulating the expression of key genes in the toll-like receptor and STAT signaling pathways, indicating its potential for development as an anti-H1N1 drug.

An influenza virus vector candidate vaccine stably expressing SARS-CoV-2 receptor-binding domain produces high and long-lasting neutralizing antibodies in mice

Viral infectious pathogens, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza virus, can cause extremely high infection rates and mortality in humans. Therefore, it is urgent to develop an effective vaccine against coronavirus and influenza virus infection. Herein, we used the influenza virus as a vector to express the SARS-CoV-2 spike receptor-binding domain (RBD) and hemagglutinin-esterase-fusion (HEF) protein of the influenza C virus. We then evaluated the feasibility and effectiveness of this design strategy through experiments in vitro and in vivo. The results showed that the chimeric viruses could stably express the HEF protein and the SARS-CoV-2 spike RBD at a high level. BALB/c mice, infected with the chimeric virus, exhibited mild clinical symptoms, yet produced high specific antibody levels against RBD and HEF, including neutralizing antibodies. Importantly, high neutralizing antibodies could be retained in the sera of mice for at least 20 weeks. Altogether, our data provided a new strategy for developing safe and effective COVID-19 and influenza virus vaccines.

Peripheral blood T cells response in human parainfluenza virus-associated lower respiratory tract infection in children

Human Parainfluenza virus (HPIV) causes lower respiratory tract infections (LRTI) mostly in young children. Respiratory viral infections may decline T cells in circulation and display enhanced pathogenicity. This study is aimed to analyze T cells alterations due to HPIV in children with LRTIs. Children (N = 152) with bronchitis or pneumonia, admitted in tertiary care hospitals were included in the study. Respiratory samples (throat or nasopharyngeal swabs) were taken and HPIV genotypes (1-4) were analyzed through RT-PCR. Peripheral blood T cells, CD3+, CD4+, CD8+, and CD19+, were analyzed in confirmed HPIV positive and healthy control group children through flow cytometry. The positivity rate of HPIV was 24.34% and the most prevalent genotype was HPIV-3 (20.40%). HPIV-1 and HPIV-2 were detected in 0.66% and 02% children respectively. The T lymphocyte counts were observed significantly reduced in children infected with HPIV-3. CD4+ cell (1580 ± 97.87) counts did not change significantly but the lowest CD8+ T cell counts (518.5 ± 74.00) were recorded. Similarly, CD3+ and CD19 cell ratios were also reduced. The CD4/CD8 ratio was significantly higher (3.12 ± 0.59) in the study population as compared to the control group (2.18 ± 0.654). Changes in the count of CD8+ T cells were more pronounced in patients with bronchiolitis and pneumonia. It is concluded that CD8+ T cells show a reduced response to HPIV-3 in children with severe LRTIs suggesting a strong association of these cells with disease severity.

β-sitosterol ameliorates influenza A virus-induced proinflammatory response and acute lung injury in mice by disrupting the cross-talk between RIG-I and IFN/STAT signaling

β-Sitosterol (24-ethyl-5-cholestene-3-ol) is a common phytosterol Chinese medical plants that has been shown to possess antioxidant and anti-inflammatory activity. In this study we investigated the effects of β-sitosterol on influenza virus-induced inflammation and acute lung injury and the molecular mechanisms. We demonstrate that β-sitosterol (150–450 μg/mL) dose-dependently suppresses inflammatory response through NF-κB and p38 mitogen-activated protein kinase (MAPK) signaling in influenza A virus (IAV)-infected cells, which was accompanied by decreased induction of interferons (IFNs) (including Type I and III IFN). Furthermore, we revealed that the anti-inflammatory effect of β-sitosterol resulted from its inhibitory effect on retinoic acid-inducible gene I (RIG-I) signaling, led to decreased STAT1 signaling, thus affecting the transcriptional activity of ISGF3 (interferon-stimulated gene factor 3) complexes and resulting in abrogation of the IAV-induced proinflammatory amplification effect in IFN-sensitized cells. Moreover, β-sitosterol treatment attenuated RIG-I-mediated apoptotic injury of alveolar epithelial cells (AEC) via downregulation of pro-apoptotic factors. In a mouse model of influenza, pre-administration of β-sitosterol (50, 200 mg·kg⁻¹·d⁻¹, i.g., for 2 days) dose-dependently ameliorated IAV-mediated recruitment of pathogenic cytotoxic T cells and immune dysregulation. In addition, pre-administration of β-sitosterol protected mice from lethal IAV infection. Our data suggest that β-sitosterol blocks the immune response mediated by RIG-I signaling and deleterious IFN production, providing a potential benefit for the treatment of influenza.

Erucic acid from Isatis indigotica Fort. suppresses influenza A virus replication and inflammation in vitro and in vivo through modulation of NF-κB and p38 MAPK pathway

Isatis indigotica Fort. (Ban-Lan-Gen) is an herbal medicine prescribed for influenza treatment. However, its active components and mode of action remain mostly unknown. In the present study, erucic acid was isolated from Isatis indigotica Fort., and subsequently its underlying mechanism against influenza A virus (IAV) infection was investigated in vitro and in vivo. Our results demonstrated that erucic acid exhibited broad-spectrum antiviral activity against IAV resulting from reduction of viral polymerase transcription activity. Erucic acid was found to exert inhibitory effects on IAV or viral (v) RNA-induced pro-inflammatory mediators as well as interferons (IFNs). The molecular mechanism by which erucic acid with antiviral and anti-inflammatory properties was attributed to inactivation of NF-κB and p38 MAPK signaling. Furthermore, the NF-κB and p38 MAPK inhibitory effect of erucic acid led to diminishing the transcriptional activity of interferon-stimulated gene factor 3 (ISGF-3), and thereby reducing IAV-triggered pro-inflammatory response amplification in IFN-β-sensitized cells. Additionally, IAV- or vRNA-triggered apoptosis of alveolar epithelial A549 cells was prevented by erucic acid. In vivo, erucic acid administration consistently displayed decreased lung viral load and viral antigens expression. Meanwhile, erucic acid markedly reduced CD8⁺ cytotoxic T lymphocyte (CTL) recruitment, pro-apoptotic signaling, hyperactivity of multiple signaling pathways, and exacerbated immune inflammation in the lung, which resulted in decreased lung injury and mortality in mice with a mouse-adapted A/FM/1/47-MA(H1N1) strain infection. Our findings provided a mechanistic basis for the action of erucic acid against IAV-mediated inflammation and injury, suggesting that erucic acid may have a therapeutic potential in the treatment of influenza.

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Erucic acid from Isatis indigotica Fort. exhibited broad-spectrum anti-influenza virus activity.

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Erucic acid reduced IAV polymerase transcription activity.

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Erucic acid suppressed IAV-triggered inflammation as well as pro-inflammatory amplification effects in IFN-sensitized cells.

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Erucic acid protected mice from lethal IAV infection.

T-lymphocyte subsets as a predictive biomarker for stroke-associated pneumonia

The aim of this study was to facilitate the clinical treatment and prognosis of stroke-associated pneumonia (SAP) by examining changes in T-lymphocyte subsets. Stroke patients admitted in Suzhou Hospital between 2014 and 2016 participated in the study. Patients were divided into a pneumonia group (50 patients) and a non-pneumonia group (254 patients) based on a diagnosis of pneumonia. Information regarding risk factors for ischemic stroke was collected from all patients using a questionnaire. Compared with non-SAP patients, SAP patients were older, dysphagic, smokers, had higher NIH stroke scale (NIHSS) scores and neutrophil: lymphocyte ratio, had higher leukocyte, neutrophil, and CD8 levels, had lower CD3, CD4, and lymphocyte levels, and had a lower CD4:CD8 ratio. Patients with a higher NIHSS score had higher CD8 levels, lower CD3 and CD4 levels, and a lower CD4:CD8 ratio. No significant differences in T-lymphocyte subsets were found between the left and right cerebral hemispheres. After adjusting for other variables, smoking, dysphagia, NIHSS score, and CD4:CD8 ratio were positively associated with SAP. The areas under the receiver operating characteristic curve for dysphagia, NIHSS score, CD4:CD8 ratio, CD4:CD8 ratio + NIHSS score, and Dysphagia+ CD4:CD8 ratio + NIHSS score were 0.583 (95% CI: 0.490-0.675), 0.791 (95% CI: 0.724-0.859), 0.676 (95% CI: 0.593-0.759), 0.846 (95% CI: 0.790-0.902), and 0.867 (95% CI: 0.815-0.918), respectively. A few T-lymphocyte subsets may increase susceptibility to pneumonia after acute ischemic stroke. Thus, the detection of T-lymphocyte subsets may predict the risk of SAP in such patients.

Development of cross-protective influenza a vaccines based on cellular responses

Seasonal influenza vaccines provide protection against matching influenza A virus (IAV) strains mainly through the induction of neutralizing serum IgG antibodies. However, these antibodies fail to confer a protective effect against mismatched IAV. This lack of efficacy against heterologous influenza strains has spurred the vaccine development community to look for other influenza vaccine concepts, which have the ability to elicit cross-protective immune responses. One of the concepts that is currently been worked on is that of influenza vaccines inducing influenza-specific T cell responses. T cells are able to lyse infected host cells, thereby clearing the virus. More interestingly, these T cells can recognize highly conserved epitopes of internal influenza proteins, making cellular responses less vulnerable to antigenic variability. T cells are therefore cross-reactive against many influenza strains, and thus are a promising concept for future influenza vaccines. Despite their potential, there are currently no T cell-based IAV vaccines on the market. Selection of the proper antigen, appropriate vaccine formulation and evaluation of the efficacy of T cell vaccines remains challenging, both in preclinical and clinical settings. In this review, we will discuss the current developments in influenza T cell vaccines, focusing on existing protein-based and novel peptide-based vaccine formulations. Furthermore, we will discuss the feasibility of influenza T cell vaccines and their possible use in the future.

Clearance of influenza virus infections by T cells: risk of collateral damage?

Influenza A viruses are a major cause of respiratory infections in humans. To protect against influenza, vaccines mainly aim at the induction of antibodies against the two surface proteins and do not protect against influenza A viruses from other subtypes. There is an increasing interest in heterosubtypic immunity that does protect against different subtypes. CD8 and CD4 T cells have a beneficial effect on the course of influenza A virus infection and can recognize conserved IAV epitopes. The T cell responses are tightly regulated to avoid collateral damage due to overreaction. Different studies have shown that an aberrant T cell response to an influenza virus infection could be harmful and could contribute to immunopathology. Here we discuss the recent findings on the balance between the beneficial and detrimental effects of T cell responses in influenza virus infections.

Oral administration of patchouli alcohol isolated from Pogostemonis Herba augments protection against influenza viral infection in mice

Seasonal influenza A infection results in considerable morbidity and mortality. The limited efficacy of available therapeutic strategies stresses the need for development and study of new molecules against influenza virus (IFV). Patchouli alcohol (PA), the major chemical constituent of Pogostemonis Herba, was previously found to strongly inhibit influenza H1N1 replication in vitro. In the present study, the in vivo anti-IFV effect of PA was investigated. In a mouse model infected with lethal levels of FM1, oral administration of PA (20 mg/kg to 80 mg/kg) for 7 d post IFV infection significantly increased the survival rate and survival time. For IFV infection at nonlethal levels, the quantity of IFV in the lungs 5 d after infection was significantly reduced after PA (20 mg/kg to 80 mg/kg) administration. Anti-IFV IgA, IgM, and IgG titers in serum on day 6 were significantly higher in the PA-treated group than the IFV-control group. Anti-IFV immune response augmentation was further confirmed by the elevated production of CD3+, CD4+, and CD8+ T cell levels in blood. Furthermore, the levels of inflammatory cytokines, including TNF-alpha, IL-10 and IFN-gamma in serum of mice, were regulated. Lung inflammation was reduced significantly after PA administration, and the effect may be mediated, at least in part, by regulating the lung levels of inflammatory cytokines. Thus, oral administration of PA appears to be able to augment protection against IFV infection in mice via enhancement of host immune responses, and attenuation of systemic and pulmonary inflammatory responses.