Perceived stress and psychological disorders in healthcare professionals: a multiple chain mediating model of effort-reward imbalance and resilience.

Background: Healthcare professionals have shown more psychological disorders such as anxiety and depression due to the nature of work, which can cause job burnout, decrease the quality of medical services, and even endanger medical safety. The aim of the study is to explore the serial multiple mediating role of effort- reward imbalance and resilience between perceived stress and psychological disorders among healthcare professionals. Methods: A cross-sectional study was conducted in China from February to April 2023. A total of 2098 healthcare professionals at a tertiary general hospital was investigated by the following self-reported questionnaires: Hospital Anxiety and Depression Scale (HADS), Perceived Stress Scale (PSS), The Effort-Reward Imbalance (ERI), Healthcare professionals Resilience Scale (MSRS). Results: Anxiety and depression are interrelated (r = 0.362, p < 0.01), and they were positively related to perceived stress (r = 0.640/0.607, p < 0.01) and ERI (r = 0.422/0.383, p < 0.01), and negatively related to resilience (r = -0.343/-0.320, p < 0.01). After controlling demographic factors, the variance in anxiety and depression was explained by perceived stress was 37.7 and 35.0%. Bootstrap analyses examining the pathway of perceived stress-ERI-resilience-anxiety revealed significant direct effects [B = 0.560, 95%CI (0.528, 0.591)], as well as indirect effects mediated independently by ERI [B = 0.045, 95%CI (0.029, 0.060)], resilience [B = 0.031, 95%CI (0.017, 0.047)], or a combination of both [B = 0.004, 95%CI (0.002, 0.007)]. Similarly, in the path of perceived stress-ERI-resilience-anxiety-depression, significant direct effects were found [B = -0.310, 95%CI(0.265, 0.351)], along with indirect effects mediated individually by ERI [B = 0.033, 95%CI(0.013, 0.052)], resilience [B = 0.014, 95%CI (0.001, 0.028)], and anxiety [B = 0.218, 95%CI (0.190, 0.246)], or by both or three together (B = 0.032). Conclusion: This study proved the hypothesis that ERI and resilience played a mediating role in perceived stress and psychological disorders, revealed the potential mechanism of anxiety in stress and depression, and proposed a solution for perceived stress to psychological distress, which can provide a basis for the intervention of healthcare professionals in the face of mental health crisis.

Analysis of Subclinical Thyroid Dysfunction and Metabolic Abnormality in 28568 Healthy People.

We analyzed the detection rates of metabolic syndrome (MetS) and subclinical thyroid dysfunction, including subclinical hyperthyroidism (SCHyper) and subclinical hypothyroidism (SCH), in healthy people, as well as their relationship. Clinical data were collected from 28,568 healthy individuals who underwent physical examinations. The detection rates of SCHyper, SCH, and MetS, as well as in different genders and ages, were analyzed. The detection rate of SCHyper and SCH in females was significantly higher than that in males (P < 0.001), but that of MetS in males was significantly higher than that in females (P < 0.001). In each age group, the detection rate of SCH in females was higher than that in males (P < 0.001). The detection rate of SCH was significantly different in different age groups (P < 0.001). The detection rates of hyperlipidemia (P < 0.001), obesity (P = 0.004), hypertension (P = 0.009), and hyperglycemia (P < 0.001) in the female SCH group were significantly higher than those in the normal group. The detection rates of hyperlipidemia (P = 0.006), obesity (P = 0.04), and hypertension (P = 0.04) in the male SCH group were higher than those in the normal group. The males with SCHyper were more prone to hyperlipidemia (P = 0.02) and obesity (P = 0.03). In addition, the female SCHyper group was not significantly different from the normal group (P > 0.05). Conclusively, the detection rate of SCHyper and SCH in females is higher than that in males, which increases with age. Attention should be paid to subclinical thyroid dysfunction in elderly people, especially females. Early individualized screening and early intervention should be carried out for people with abnormal metabolism.

Psychology, stress, insomnia, and resilience of medical staff in China during the COVID-19 policy opening: a cross-sectional survey.

Background: Since 8 January 2023 China has liberalized its control of COVID-19. In a short period of time, the infection rate of COVID-19 in China has risen rapidly, which has brought a heavy burden to medical staff. This study aimed to investigate the psychological status, stress, insomnia, effort-reward imbalance, resilience, and influencing factors of medical staff in China during the period of epidemic policy liberalization. Methods: This survey was conducted from 6 February to 27 March 2023 with non-random sampling. An online questionnaire survey was conducted using HADS, PSS-14, ISI, ERI, and the resilience assessment scale for medical staff. The levels of psychological, stress, insomnia, effort-reward imbalance, and resilience of medical staff during the pandemic policy opening period were measured. Results: A total of 2,038 valid questionnaires were collected. 68.5% and 53.9% of medical staff had different degrees of anxiety and depression, respectively. Excessive stress, insomnia, and high effort and low reward were 40.2%, 43.2%, and 14.2%, respectively. Gender, Profession, education level, and age are important factors that lead to anxiety and depression. Women, nurses, higher education, longer working years and hours, high effort, and low reward are risk factors for the above conditions. There was a certain correlation among the five scales, among which anxiety, depression, stress, insomnia, effort-reward imbalance, and other factors were positively correlated, while resilience was negatively correlated with these factors. Conclusion: This study found that anxiety, depression, stress, insomnia, and other psychological problems of medical staff in China during the policy opening period of COVID-19 were more serious than before. At the individual and organizational levels, it is necessary to improve the well-being of medical staff, optimize the allocation of human resources, and promote the mental health of medical staff with a focus on prevention and mitigation, with the entry point of improving resilience and preventing the effort-reward imbalance.

Hope and depression: the mediating role of social support and spiritual coping in advanced cancer patients.

BACKGROUND: Depression is the most common mental disorder in patients with advanced cancer, which may lead to poor prognosis and low survival rate. This study aims to explore the serial multiple mediating roles of social support and spiritual coping between hope and depression among patients with advanced cancer. METHODS: A cross-sectional study was conducted in China between May and August 2020. A total of 442 advanced cancer patients were investigated by the following self-reported questionnaires: Herth Hope Index (HHI), Spiritual Coping Questionnaire (SCQ, Chinese version), Social Support Rating Scale (SSRS), Hospital Anxiety and Depression Scale (HADS). RESULTS: Depression was negatively correlated with hope, social support, and positive spiritual coping (P < 0.01), and positively correlated with negative spiritual coping (P < 0.01). Hope explained 16.0% of the variance in depression. Bootstrap analyses of the hope--social support--positive spiritual coping--depression showed that there were direct [B = -0.220, 95%CI(- 0.354, - 0.072)] and indirect effects of hope on depression mediated solely by social support [B = -0.122, 95%CI(- 0.200, - 0.066)] and positive spiritual coping [B = -0.112, 95%CI(- 0.217,-0.025)], or by both together [B = -0.014, 95%CI(- 0.038,-0.003)]. Similarly, the hope--social support--negative spiritual coping--depression showed that there were direct [B = -0.302, 95%CI(- 0.404, - 0.190)] and indirect effects of hope on depression mediated solely by social support [B = -0.126, 95%CI(- 0.205, - 0.071)] and negative spiritual coping [B = -0.033, 95%CI(- 0.080,-0.002)], or by both together [B = -0.010, 95%CI(- 0.030,-0.001)]. CONCLUSIONS: This study proves the hypothesis that social support and spiritual coping play intermediary roles between hope and depression. Interventions established through hope, social support and spiritual coping can effectively prevent depression from occurring.

Glutamate blunts cell-killing effects of neutrophils in tumor microenvironment.

Neutrophils are the first defenders of the innate system for injury and infection. They have gradually been recognized as important participants in tumor initiation and development due to their heterogeneity and plasticity. In the tumor microenvironment (TME), neutrophils can exert antitumor and protumor functions, depending on the surroundings. Tumor cells systemically alter intracellular amino acid (AA) metabolism and extracellular AA distribution to meet their proliferation need, leading to metabolic reprogramming and TME reshaping. However, the underlying mechanisms that determine how altered AAs affect neutrophils in TME are less-explored. Here, we identified that abundant glutamate releasing from tumor cells blunted neutrophils' cell-killing effects toward tumor cells in vitro and in vivo. Mass spectrometric detection, flow cytometry, and western blot experiments proved that increased levels of pSTAT3/RAB10/ARF4, mediated by glutamate, were accompanied with immunosuppressive phenotypes of neutrophils in TME. We also discovered that riluzole, an FDA-approved glutamate release inhibitor, significantly inhibited tumor growth by restoring neutrophils' cell-killing effects and decreasing glutamate secretion from tumor cells. These findings highlight the importance of tumor-released glutamate on neutrophil transformation in TME, providing new possible cancer treatments targeting altered glutamate metabolism.

Associations between food-specific IgG and health outcomes in an asymptomatic physical examination cohort.

BACKGROUND: Although the association of food-specific IgG with the development and progression of specific diseases was shown by many studies, it is also present in the population without clinical symptoms. However, the association between food-specific IgG and physical examination outcomes in healthy people has not been studied yet. METHODS: An asymptomatic physical examination cohort (APEC) was selected according to the inclusion and exclusion criteria, the physical examination data were compared between IgG positive and IgG negative groups, and their odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression. RESULTS: The data of 28,292 subjects were included in the analysis. The overall IgG positive rate was up to 52.30%, mostly with mild to moderate IgG positivity. The multivariable Logistic regression showed the prevalence of hypertriglyceridemia, abnormal fasting blood glucose and overweight was lower in the IgG (+) positive group (OR 0.87, 95% CI 0.83-0.92; OR 0.93, 95% CI 0.87-0.99; OR 0.92, 95% CI 0.87-0.96) but there was a higher prevalence of thyroid disease (OR 1.09, 95% CI 1.04-1.15). CONCLUSION: Food-specific IgG positivity was widespread in the APEC and was associated with lower prevalence of hypertriglyceridemia, abnormal fasting blood glucose and overweight. The underlying physiological mechanism merits further study.

The association between hypertension and the risk of gallstone disease: a cross-sectional study.

BACKGROUND: To explore the association between hypertension and the risk of gallstone disease. METHODS: We collected the data about the subjects receiving physical examination. Gallstone disease was diagnosed by abdominal ultrasound. Multivariable logistic regression was used to study the association between blood pressure and the risk of gallstone disease. SPSS version 23.0 was used for statistical analysis, and two-tailed P < 0.05 was defined as statistically significant. RESULTS: A total of 318,403 people were included in the study and 171,276 (53.8%) of them were men and 147,127 (46.2%) were women. Among them, 27,463 (8.6%) were diagnosed with gallstone disease on ultrasound examination, with 12,452 (3.9%) cases of gallstones and 15,017 (4.7%) cases of cholecystectomy. Multivariable logistic regression showed that hypertension was significantly associated with the risk of gallstone disease (OR = 1.05; 95% CI: 1.02-1.10; P = 0.03) and gallstones (OR = 1.12; 95% CI: 1.06-1.19; P < 0.01) and the association between hypertension and gallstone disease was stronger in women than in men. However, hypertension was not significantly correlated with cholecystectomy (OR = 0.99; 95% CI: 0.95-1.04; P = 0.85). Additionally, results showed that with the severity of hypertension increased, the risk of gallstone disease was also marked elevated (P for trend < 0.001). CONCLUSIONS: The gallstone disease was prevalent and hypertension is significantly associated with the gallstone disease risk with a significant dose-response association. This study showed that the association between hypertension and cholecystectomy was not statistically significant, maybe hypertension correlated with gallstones but not with symptomatic gallstone disease which would require cholecystectomy.

Body mass index in relation to prostate-specific antigen-related parameters.

BACKGROUND: Only a few previous studies conducted to assess the association between body mass index (BMI) and prostate-specific antigen (PSA) related parameters have taken prostate volume (PV) and blood volume (BV) into consideration. The objective of this study was to assess the relationship between BMI and parameters of PSA concentrations in Chinese adult men. METHODS: A total of 86,912 men who have received annual physical examination at the First Affiliated Hospital of Army Medical University from 1 January 2011 to 31 December 2018 were included in this study. Linear regression models were performed to assess the relationship between BMI, PV, BV and PSA, and analyze the correlation between BMI and PSA, PSA density and PSA mass. RESULTS: The univariable linear regression showed that PV, BV, systolic pressure (SBP), pulse, fasting blood glucose (FBG) and age were significantly associated with PSA level (P < 0.05). The multivariate linear regression demonstrated that PV, BV, FBG and age were significantly associated with PSA level (P < 0.05). WHR and BMI is negatively associated with PSA and PSA density (P < 0.05), and no statistically significant association was found between PSA mass and WHR and (P = 0.268) or BMI (P = 0.608). CONCLUSIONS: The findings of this large-sample, hospital-based study in China indicate that PV was positively associated with serum PSA concentrations, while BMI and BV were inversely related with PSA levels. PSA mass can be used to estimate the PSA concentration without being affected by obesity in Chinese men.

Decreased phosphorylation facilitates the degradation of the endogenous protective molecule c-Ski in vascular smooth muscle cells.

The dysfunction of vascular smooth muscle cells (VSMCs) is critical for atherosclerosis (AS) progression. Autophagy is indispensable during phenotypic switching and proliferation of VSMCs, contribute to AS development. Cellular Sloan-Kettering Institute (c-Ski), the repressor of TGF-ß signaling, is involved in diverse physiological and pathological processes. We previously defined c-Ski also as an endogenous protective molecule against AS via inhibiting abnormal proliferation and autophagy of VSMCs. However, the endogenous level of c-Ski in VSMCs is markedly decreased during the progression of AS, so that the protective effect is drastically weakened. Elucidating the molecular mechanisms is key to the understanding of AS development and treatment. We determined that oxidized low-density lipoprotein (ox-LDL) and platelet-derived growth factor (PDGF) directly induced the degradation of c-Ski protein, closely associated with reducing its phosphorylation. Serine383 (S383) was identified as the crucial phosphorylation site for stabilizing protein expression and nuclear location of c-Ski, which was responsible for its transcriptional suppression of autophagy-related genes. Decreased S383 phosphorylation facilitated nuclear export and degradation of c-Ski, thereby lessened its inhibitory effect on induction of autophagy genes. These findings provide a novel view of c-Ski modification and function modulation under some vascular injury factors, which point to a new potential therapeutic strategy by targeting c-Ski.

Dynamic SARS-CoV-2-Specific Immunity in Critically Ill Patients With Hypertension.

Background: The current outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses an unprecedented health crisis. The most common chronic illness among patients infected with SARS-CoV-2 is hypertension. Immune dysregulation plays an important role in SARS-CoV-2 infection and in the development of hypertension; however, the dynamic immunological characteristics of COVID-19 patients with hypertension remain largely unclear. Methods: In total, 258 hypertensive patients infected with SARS-CoV-2 were included in this study. CD38+HLA-DR+ and CD38+PD-1+ CD8+ T cells, IFNγ+CD4+ and IFNγ+CD8+ T cells, the titers of IgG, IgM, and IgA against SARS-CoV-2 spike protein, and SARS-CoV-2 throat viral loads were measured weekly over 4 weeks after the onset of symptoms. Clinical outcomes were also monitored. Findings: CD4+ T lymphopenia was observed in 100% of the severe and critical cases. Compared with the surviving patients, the patients with fatal outcomes exhibited high and prolonged expression of CD38+HLA-DR+ and CD38+PD-1+ on CD8+ T cells, low expression of SARS-CoV-2-specific IFNγ+CD4+ and IFNγ+CD8+ T cells, low titers of IgG, IgM, and IgA against SARS-CoV-2 spike protein, and high SARS-CoV-2 viral load during the illness. In the surviving patients, the viral load was significantly inversely correlated with SARS-CoV-2-specific IFNγ+CD8+and IFNγ+CD4+ T cells, IgG, IgM, and IgA. Interpretation: T lymphopenia is common in critical or severe COVID-19 cases with hypertension. Prolonged activation and exhaustion of CD8+ T cells were associated with severe disease. The delayed SARS-CoV-2-specific antibody responses may be insufficient for overcoming severe SARS-CoV-2 infection in the absence of SARS-CoV-2-specific cellular responses.

Effects of walkability on physical activity and obesity: a prospective observational study protocol.

INTRODUCTION: The prevalence of overweight and obesity is increasing worldwide, which could lead to a set of chronic and metabolic diseases. Physical activity is a modifiable factor for obesity, which was reported to be correlated with the built environment. However, the effects of the built environment on physical activity are not consistent. Walkability is a convenient way to assess the built environment. We aim to prospectively explore the relationship among walkability, physical activity and obesity in Chinese participants in Chongqing, a hilly city and provide evidence for future urban planning. METHODS AND ANALYSIS: Participants will be recruited from people who receive health examination in the Health Management Centre, the First Affiliated Hospital to Army Medical University. Exposure variables are WalkScores calculated within the areas around workplace and residential addresses of participants. The primary outcomes are body mass index measured through health examination at baseline and follow-ups, and daily walking steps recorded by WeChat mini application for 30 days after every time of health examination. Other health-related data of the participants will also be collected. Multivariate regression analysis will be performed to examine the relationship between exposure variables and outcomes. ETHICS AND DISSEMINATION: The Protocol is approved by the Ethics Committee of the First Affiliated Hospital to Army Medical University (KY201839). The results will be actively disseminated through peer-review journals and conference publications. REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR1800017680).

The Prevalence of Single and Multiple Thyroid Nodules and Its Association with Metabolic Diseases in Chinese: A Cross-Sectional Study.

PURPOSE: The present study aims to investigate the prevalence of single and multiple thyroid nodules and its association with metabolic diseases in subjects who participated in the heath examination in China. METHODS: This is a cross-sectional study. The participants who attend the physical examination at the Health Management Center of Southwest Hospital, Army Military Medical University, between January 2014 and December 2018, were included. Thyroid nodules were diagnosed by thyroid ultrasound. Multivariable logistic regression was used to investigate the association between metabolic diseases and nodular thyroid disease. RESULTS: A total of 9,146 subjects were included in this study; of them, 2,961 were diagnosed with thyroid nodules, with a prevalence of 32.4%. The prevalence in women was significantly higher than that in men (45.2% vs 26.0%; χ 2 = 339.56, P < 0.001), and the prevalence was gradually increased with age (Z = 20.05, P < 0.001), and the prevalence was gradually increased with age (. CONCLUSIONS: The prevalence of thyroid nodules was relatively high. Age, female gender, and diabetes are positively associated with nodular thyroid disease. High LDL cholesterolemia is more likely to be associated with multiple thyroid sarcoidosis.

Relationship between body mass index and concentrations of prostate specific antigen: a cross-sectional study.

The possible relationship between body mass index (BMI) and prostate-specific antigen (PSA) concentrations is controversial. The objective of this study was to assess the relationship between BMI and PSA concentrations in Chinese men. A total of 81,122 men who had undergone annual medical examinations at the First Affiliated Hospital of Army Medical University between 1 January 2011 and 31 December 2018 were included. Univariate and multivariate linear regression models were used to assess the relationship between BMI and PSA concentrations. The nonlinear relationship was analyzed using a generalized additive model with a spline smoothing function. Subsequently, a stratified linear regression model was used for subgroup analysis. The mean age and BMI of the participants were 45.91 ± 12.21 years and 24.79 ± 3.11 kg/m2, respectively. After adjustment for age, waist circumference-hip circumference ratio, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase and aspartate aminotransferase, BMI was negatively related to PSA level (p < .001). A nonlinear relationship was detected, and different relationships between BMI and PSA concentrations were observed on each side of the inflection point (BMI = 23.11 kg/m2). Our study revealed an inverse, nonlinear relationship between BMI and PSA concentrations. Thus, this relationship may be a concern when establishing reference intervals or decision limits for PSA concentrations.

Antioxidants: potential antiviral agents for Japanese encephalitis virus infection.

Japanese encephalitis (JE) is prevalent throughout eastern and southern Asia and the Pacific Rim. It is caused by the JE virus (JEV), which belongs to the family Flaviviridae. Despite the importance of JE, little is known about its pathogenesis. The role of oxidative stress in the pathogenesis of viral infections has led to increased interest in its role in JEV infections. This review focuses mainly on the role of oxidative stress in the pathogenesis of JEV infection and the antiviral effect of antioxidant agents in inhibiting JEV production. First, this review summarizes the pathogenesis of JE. The pathological changes include neuronal death, astrocyte activation, and microglial proliferation. Second, the relationship between oxidative stress and JEV infection is explored. JEV infection induces the generation of oxidants and exhausts the supply of antioxidants, which activates specific signaling pathways. Finally, the therapeutic efficacy of a variety of antioxidants as antiviral agents, including minocycline, arctigenin, fenofibrate, and curcumin, was studied. In conclusion, antioxidants are likely to be developed into antiviral agents for the treatment of JE.

Identification of B cell epitopes of dengue virus 2 NS3 protein by monoclonal antibody.

Dengue virus is a major international public health concern, and there is a lack of available effective vaccines. Virus-specific epitopes could help in developing epitope peptide vaccine. Previously, a neutralizing monoclonal antibody (mAb) 4F5 against nonstructural protein 3 (NS3) of dengue virus 2 (DV2) was developed in our lab. In this work, the B cell epitope recognized by mAb 4F5 was identified using the phage-displayed peptide library. The results of the binding assay and competitive inhibition assay indicated that the peptides, residues 460-469 (U460-469 RVGRNPKNEN) of DV2 NS3 protein, were the B cell epitopes recognized by mAb 4F5. Furthermore, the epitope peptides and a control peptide were synthesized and then immunized female BALB/c mice. ELISA analysis showed that immunization with synthesized epitope peptide elicited a high level of antibody in mice, and immunofluorescent staining showed that the antisera from fusion epitope-immunized mice also responded to DV2 NS3 protein, which further characterized the specific response of the present epitope peptide. Therefore, the present work revealed the specificity of the newly identified epitope (U460-469) of DV2 NS3 protein, which may shed light on dengue virus (DV) vaccine design, DV pathogenesis study, and even DV diagnostic reagent development.

Myosin Vc, a member of the actin motor family associated with Rab8, is involved in the release of DV2 from HepG2 cells.

OBJECTIVE: The pathogenesis of the dengue virus (DV) infection has not been well defined. We have reported that actin and Rab8 are involved in DV2 infection. Myosin Vc (Myo5c) is a novel member of the class V myosins and regulates the actin-mediated membrane trafficking associated with Rab8. In this study, the involvement of Myo5c in the release of DV2 was investigated in HpeG2 cells. METHODS: Distributions of actin, Myo5c, DV2 and Rab8 were revealed by fluorescent staining. HepG2(Myo5c-tail) cells expressing a dominant-negative mutant of Myo5c were constructed by transfection and were assessed by Western blotting. The viral titers were detected by plaque assay, and the expression of Rab8 was analyzed by flow cytometry. RESULTS: DV2 infection altered the distribution pattern of Myo5c, which might be associated with the depolymerization of actin, though colocalization rates of Myo5c with DV2 or actin were low. Furthermore, the release of DV2, but not the intracellular viral production, was reduced from HepG2(Myo5c-tail) cells. Moreover, Myo5c colocalized with Rab8 and an increase of Rab8 was associated with the decrease of the viral release caused by the Myo5c tail. CONCLUSIONS: Our data suggest that Myo5c associated with Rab8 is involved in the release of DV2 from HepG2 cells.

Entry of dengue virus serotype 2 into ECV304 cells depends on clathrin-dependent endocytosis, but not on caveolae-dependent endocytosis.

Caveolae- and clathrin-mediated endocytosis are major internalization pathways used by several pathogens; however, their distinctive roles in dengue virus (DV) entry have not been addressed. In this study, we compared the involvement of caveolae- and clathrin-mediated endocytosis in the infectious entry of DV serotype 2 (DV2) into human endothelial-like ECV304 cells. Confocal microscopy study on DV2-infected cells showed that viral antigens were co-localized with clathrin heavy chains, epidermal growth factor pathway substrate clone 15 (Eps15), and adaptin-alpha, but not with caveolin-1. Treatment with chlorpromazine, which inhibits clathrin-dependent endocytosis, led to reduced virus entry into cells, whereas treatment with nystatin, a caveolae inhibitory agent, did not. Furthermore, gene silencing of Eps15 resulted in an average of 75% reduced infection of ECV304 cells by DV2. Our results demonstrated that DV2 enters ECV304 cells by clathrin-dependent endocytosis, not by caveolae-dependent endocytosis.

Passive protection assay of monoclonal antibodies against dengue virus in suckling mice.

Dengue fever and dengue hemorrhagic fever/dengue shock syndrome are highly infectious diseases caused by dengue virus (DV). Specific monoclonal antibodies (mAbs) against DV are vital for diagnosis, pathological studies, and passive immune therapy. In this study, purified DV serotype 2 (DV2) was used as antigen and BALB/c mice were immunized to induce specific antibodies. We established five hybridoma cell lines, called 78#, 1E7, 7F7, 8F12, and 8H1, respectively, and evaluated them by enzyme-linked immunosorbent assay, indirect immunofluorescence assay, Western blot, plaque reduction neutralization test, and suckling mice protection assay. Lines 78#, 1E7, 7F7, and 8F12 showed a neutralizing effect, and lines 78#, 1E7, 8F12, and 8H1 recognized envelope glycoprotein of DV2. Among them, lines 78# and 8F12 had stronger neutralizing ability in vitro and could protect some suckling mice from virus challenge. Our results demonstrate that immunization with purified virion is efficient for the production of specific neutralizing mAbs against DV2, and these mAbs could be useful tools for studying or treating DV infection.

Production of a monoclonal antibody against non-structural protein 3 of dengue-2 virus by intrasplenic injection.

Dengue fever and dengue hemorrhagic fever/dengue shock syndrome are highly infectious diseases caused by dengue virus (DV). DV non-structural protein 3 (NS3) is known to possess ATPase, helicase, and protease activity that is a constitutive part of the replication complex of DV. In this study, we discuss the cloning, expression, and purification of the DV-2 NS3 protein to immunize mice by intrasplenic injection and then to generate a monoclonal antibody (MAb). One MAb, named 4F5, was obtained and it was specific to NS3 of DV-2. Immunofluorescence show that 4F5 recognizes the native protein in infected ECV304 cells. Likewise, C6/36-infected lysates were used in Western blot analysis, and we observed the specific characteristic band that defines NS3. We conclude that MAb 4F5 may be a useful tool, not only to study the replicative process of DV, but also to generate specific diagnostic tools for DV infection.

Vimentin is required for dengue virus serotype 2 infection but microtubules are not necessary for this process.

The present study investigated the effect of microtubules (MTs) and vimentin during dengue virus serotype 2 (DV2) infection. Immunostaining showed that DV2 infection induced MT and vimentin reorganization. Colocalization of DV2 antigens with MTs or vimentin were often observed in ECV304 cells. MT-disrupting agents could enhance DV2 release but did not affect other steps of virus replication. In contrast, disruption of vimentin inhibited DV2 infection. Our results suggest that an MT-dependent mechanism may not be necessary for DV2 infection, and MT disruption may promote DV2 release. However, vimentin is required for DV2 infection.