Selenium-GPX4 axis protects follicular helper T cells from ferroptosis.

Follicular helper T (TFH) cells are a specialized subset of CD4+ T cells that essentially support germinal center responses where high-affinity and long-lived humoral immunity is generated. The regulation of TFH cell survival remains unclear. Here we report that TFH cells show intensified lipid peroxidation and altered mitochondrial morphology, resembling the features of ferroptosis, a form of programmed cell death that is driven by iron-dependent accumulation of lipid peroxidation. Glutathione peroxidase 4 (GPX4) is the major lipid peroxidation scavenger and is necessary for TFH cell survival. The deletion of GPX4 in T cells selectively abrogated TFH cells and germinal center responses in immunized mice. Selenium supplementation enhanced GPX4 expression in T cells, increased TFH cell numbers and promoted antibody responses in immunized mice and young adults after influenza vaccination. Our findings reveal the central role of the selenium-GPX4-ferroptosis axis in regulating TFH homeostasis, which can be targeted to enhance TFH cell function in infection and following vaccination.

Therapeutic vaccination with lentiviral vector in HBV-persistent mice and two inactive HBsAg carriers.

BACKGROUND & AIMS: Immunotherapy for chronic hepatitis B virus (HBV) infection has not yet demonstrated sufficient efficacy. We developed a non-integrative lentiviral-vectored therapeutic vaccine for chronic hepatitis B and tested its antiviral effects in HBV-persistent mice and two inactive HBsAg carriers. METHODS: Lentiviral vectors (LVs) encoding the core, preS1, or large HBsAg (LHBs) proteins of HBV were evaluated for immunogenicity in HBV-naïve mice and therapeutic efficacy in a murine model of chronic HBV infection. In addition, two inactive HBsAg carriers each received two doses of 5×107 transduction units (TU) or 1×108 TU of lentiviral-vectored LHBs (LV-LHBs), respectively. The endpoints were safety, LHBs-specific T-cell responses, and serum HBsAg levels during a 24-week follow-up. RESULTS: In the mouse models, LV-LHBs was the most promising in eliciting robust antigen-specific T cells and in reducing the levels of serum HBsAg and viral load. By the end of the 34-week observation period, six out of ten (60%) HBV-persistent mice vaccinated with LV-LHBs achieved serum HBsAg loss and significant depletion of HBV-positive hepatocytes in the liver. In the two inactive HBsAg carriers, vaccination with LV-LHBs induced a considerable increase in the number of peripheral LHBs-specific T cells in one patient, and a weak but detectable response in the other, accompanied by a sustained reduction of HBsAg (-0.31 log10 IU/ml and -0.46 log10 IU/ml, respectively) from baseline to nadir. CONCLUSIONS: A lentiviral-vectored therapeutic vaccine for chronic HBV infection demonstrated the potential to improve HBV-specific T-cell responses and deplete HBV-positive hepatocytes, leading to a sustained loss or reduction of serum HBsAg. IMPACT AND IMPLICATIONS: Chronic HBV infection is characterized by an extremely low number and profound hypo-responsiveness of HBV-specific T cells. Therapeutic vaccines are designed to improve HBV-specific T-cell responses. We show that immunization with a lentiviral-vectored therapeutic HBV vaccine was able to expand HBV-specific T cells in vivo, leading to reductions of HBV-positive hepatocytes and serum HBsAg.

Analysis of unsuccessful tests and the effect of prolonged clinical sample preprocessing in the GeneXpert MTB/RIF assay.

BACKGROUND: The GeneXpert MTB/RIF (Xpert) assay is a widely used technology for detecting Mycobacterium tuberculosis (MTB) in clinical samples. However, the study on the failure of the Xpert assay during routine implementation and its potential solutions is limited. METHODS: We retrospectively analyzed the records of unsuccessful tests in the Xpert and the GeneXpert MTB/RIF Ultra (Ultra) assays between April 2017 and April 2021 at the Shanghai Public Health Clinical Center. To further investigate the effect of prolonged preprocessing on clinical sputum, an additional 120 sputum samples were collected for Xpert testing after 15 min, 3 h, and 6 h preprocessing. The analysis was performed by SPSS version 19.0 software. RESULTS: A total of 11,314 test records were analyzed, of which 268 (2.37%) had unsuccessful test results. Among these, 221 (1.95%) were reported as "Error", 43 (0.38%) as "Invalid", and 4 (0.04%) as "No result". The most common clinical specimen for Xpert tests was sputum, accounting for 114 (2.17%) unsuccessful tests. The failure rate of urine specimens was lower than that of sputum (OR = 0.12, 95% CI: 0.02-0.88, χ2 = 6.22, p = 0.021). In contrast, the failure rate of stool specimens was approximately twice as high as that of sputum (OR = 1.93, 95% CI: 1.09-3.40, χ2 = 5.35, p = 0.014). In the prolonged preprocessing experiment, 102 cases (85%) yielded consistent results in Xpert tests. Furthermore, 7 cases (5.83%) detected an increase in MTB load, 8 cases (6.67%) detected a decrease in MTB load, and 3 cases (2.5%) yielded incongruent results in MTB and rifampicin resistance detection. CONCLUSIONS: The primary cause of unsuccessful tests in the Xpert assay was reported as "Error". Despite varying failure rates depending on the samples, the Xpert assay can be applied to extrapulmonary samples. For paucibacillary specimens, retesting the remaining preprocessed mixture should be carefully considered.

Unexpectedly higher levels of anti-orthopoxvirus neutralizing antibodies are observed among gay men than general adult population.

BACKGROUND: The confirmed cases in the current outbreak of Monkeypox are predominantly identified in the networks of men who have sex with men (MSM). The preexisting antibodies may profoundly impact the transmission of monkeypox virus (MPXV), however the current-day prevalence of antibodies against MPXV among gay men is not well characterized. METHODS: A cohort of gay men (n = 326) and a cohort of the general adult population (n = 295) were enrolled in this study. Binding antibodies responses against MPXV/vaccinia and neutralizing antibody responses against vaccinia virus (Tiantan strain) were measured. The antibody responses of these two cohorts were then compared, as well as the responses of individuals born before and in/after 1981 (when the smallpox vaccination ceased in China). Finally, the correlation between the anti-MPXV antibody responses and the anti-vaccinia antibody responses, and the associations between preexisting anti-orthopoxvirus antibody responses and the diagnosed sexually transmitted infections (STIs) in the MSM cohort were analyzed separately. RESULTS: Our data showed that binding antibodies against MPXV H3, A29, A35, E8, B6, M1 proteins and vaccinia whole-virus lysate could be detected in individuals born both before and in/after 1981, of which the prevalence of anti-vaccinia binding antibodies was significantly higher among individuals born before 1981 in the general population cohort. Moreover, we unexpectedly found that the positive rates of binding antibody responses against MPXV H3, A29, A35, E8 and M1 proteins were significantly lower among individuals of the MSM cohort born in/after 1981, but the positive rates of anti-MPXV B6 and anti-vaccinia neutralizing antibody responses were significantly higher among these individuals compared to those of age-matched participants in the general population cohort. Additionally, we demonstrated that the positive and negative rates of anti-MPXV antibody responses were associated with the anti-vaccinia antibody responses among individuals born before 1981 in the general population cohort, but no significant association was observed among individuals born in/after 1981 in both cohorts. The positive rates of both the binding and the neutralizing antibody responses were comparable between individuals with and without diagnosed STIs in the MSM cohort. CONCLUSIONS: Anti-MPXV and anti-vaccinia antibodies could be readily detected in an MSM cohort and a general population cohort. And a higher level of anti-vaccinia neutralizing antibody responses was observed among individuals who did not get vaccinated against smallpox in the MSM cohort compared to age-matched individuals in the general population cohort.

An inter-correlated cytokine network identified at the center of cytokine storm predicted COVID-19 prognosis.

The hyper-inflammatory response is thought to be a major cause of acute respiratory distress syndrome (ARDS) in patients with COVID-19. Although multiple cytokines are reportedly associated with disease severity, the key mediators of SARS-CoV-2 induced cytokine storm and their predictive values have not been fully elucidated. The present study analyzed maximal and early (within 10 days after disease onset) concentrations of 12-plex cytokines in plasma. We found consistently elevated plasma levels of IL-6, IL-8 and IL-5 in patients who were deceased compared with those who had mild/moderate or severe disease. The early plasma concentrations of IFN-a and IL-2 positively correlated with the length of the disease course. Moreover, correlation network analysis showed that IL-6, IL-8, and IL-5 located at the center of an inter-correlated cytokine network. These findings suggested that IL-8, IL-6, IL-5 might play central roles in cytokine storms associated with COVID-19 and that the early detection of multiple plasma cytokines might help to predict the prognosis of this disease.

Development and Implementation of a Pediatric Nursing-Clinical Decision Support System for Hyperthermia: A Pre- and Post-test.

This article describes the development process and application of the Pediatric Nursing-Clinical Decision Support System for Hyperthermia. Firstly, we formed the Pediatric Nursing-Knowledge Base for Hyperthermia, which combines publicly available clinical practice guidelines and nursing routines of hyperthermia management. Then, following the nursing process framework, the system was developed using clinical decision support technology. Finally, a pre- and post-test were adopted to examine the effectiveness, usability, and feasibility before (1st to 31st of August 2018) and after (1st to 31st of December 2019) using the system. Its effectiveness was examined by analysis of nursing records' quality, including completeness of nursing assessment, timeliness of nursing diagnosis, individualization of nursing interventions, and timeliness of nursing evaluation. Its usability and feasibility were assessed using the Clinical Nursing Information System Effectiveness Evaluation Scale. There was a significant difference between the two groups in effectiveness, usability, and feasibility. Although the system was developed specifically for our hospital workflow and processes, the Pediatric Nursing-Knowledge Base for Hyperthermia and workflow for hyperthermia management in this study can be used as a reference to other hospitals.

Interleukin-21 enhances the antibody avidity elicited by DNA prime and MVA boost vaccine.

Enhancement of the magnitude or affinity of protective antibodies (Abs) induced by vaccine adjuvant is highly desirable to prevent challenging pathogens such as HIV-1. IL-21 plays a crucial role in germinal center reactions during humoral immune responses. However, the effect of IL-21 as a vaccine adjuvant on the quantity and quality of antigen-specific Abs elicited by DNA prime and MVA boost vaccine, a commonly used vaccine strategy, remains unknown. To close this knowledge gap, female adult B6N mice were primed with DNA vaccine twice (days 0, 14, 100 µg, I.M.) and boosted with MVA vaccine (day 28, 2 × 107 pfu, I.M.) with or without an IL-21 DNA adjuvant (days 3, 17, 31, 40 µg, I.M.), in which HIV-1 gag was expressed as a model antigen. With the addition of an IL-21 adjuvant, we found significantly increased avidity of antigen-specific Abs at multiple time points in a longitudinal follow up. Collectively, our results suggest that an IL-21 immune adjuvant can significantly increase Ab quality induced by heterologous DNA-MVA prime-boost vaccine strategy.

Altered Ratio of T Follicular Helper Cells to T Follicular Regulatory Cells Correlates with Autoreactive Antibody Response in Simian Immunodeficiency Virus-Infected Rhesus Macaques.

Individuals with chronic HIV-1 infection have an increased prevalence of autoreactive Abs. Many of the isolated HIV broadly neutralizing Abs from these individuals are also autoreactive. However, the underlying mechanism(s) that produce these autoreactive broadly neutralizing Abs remains largely unknown. The highly regulated coordination among B cells, T follicular helper (TFH) cells, and T follicular regulatory (TFR) cells in germinal centers (GCs) of peripheral lymphatic tissues (LTs) is essential for defense against pathogens while also restricting autoreactive responses. We hypothesized that an altered ratio of TFH/TFR cells in the GC contributes to the increased prevalence of autoreactive Abs in chronic HIV infection. We tested this hypothesis using a rhesus macaque (RM) SIV model. We measured the frequency of TFH cells, TFR cells, and GC B cells in LTs and anti-dsDNA and anti-phospholipid Abs from Indian RMs, with and without SIV infection. We found that the frequency of anti-dsDNA and anti-phospholipid Abs was much higher in chronically infected RMs (83.3% [5/6] and 66.7% [4/6]) than in acutely infected RMs (33.3% [2/6] and 18.6% [1/6]) and uninfected RMs (0% [0/6] and 18.6% [1/6]). The increased ratio of TFH/TFR cells in SIV infection correlated with anti-dsDNA and anti-phospholipid autoreactive Ab levels, whereas the frequency of TFR cells alone did not correlate with the levels of autoreactive Abs. Our results provide direct evidence that the ratio of TFH/TFR cells in LTs is critical for regulating autoreactive Ab production in chronic SIV infection and possibly, by extension, in chronic HIV-1 infection.

A DNA Vaccine Expressing Consensus Hemagglutinin-Esterase Fusion Protein Protected Guinea Pigs from Infection by Two Lineages of Influenza D Virus.

Two lineages of influenza D virus (IDV) have been found to infect cattle and promote bovine respiratory disease complex, one of the most commonly diagnosed causes of morbidity and mortality within the cattle industry. Furthermore, IDV can infect other economically important domestic livestock, including pigs, and has the potential to infect humans, which necessitates the need for an efficacious vaccine. In this study, we designed a DNA vaccine expressing consensus hemagglutinin-esterase fusion (HEF) protein (FluD-Vax) and tested its protective efficacy against two lineages of IDV (D/OK and D/660) in guinea pigs. Animals that received FluD-Vax (n = 12) developed appreciable titers of neutralizing antibodies against IDV lineage representatives, D/OK and D/660. Importantly, vaccinated animals were protected against intranasal challenge with IDV [3 × 105 50% tissue culture infective dose(s) (TCID50)] D/OK (n = 6) or D/600 (n = 6), based on the absence of viral RNA in necropsied tissues (5 and 7 days postchallenge) using quantitative reverse transcription-PCR and in situ hybridization. In contrast, animals that received a sham DNA vaccine (n = 12) had no detectable neutralizing antibodies against IDV, and viral RNA was readily detectable in respiratory tract tissues after intranasal challenge (3 × 105 TCID50) with IDV D/OK (n = 6) or D/660 (n = 6). Using a TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) assay, we found that IDV D/OK and D/600 infections induced apoptosis in epithelial cells lining alveoli and bronchioles, as well as nonepithelial cells in lung tissues. Our results demonstrate for the first time that the consensus IDV HEF DNA vaccine can elicit complete protection against infection from two lineages of IDV in the guinea pig model.IMPORTANCE Influenza D virus (IDV) infection has been associated with bovine respiratory disease complex, one of the most devastating diseases of the cattle population. Moreover, with broad host range and high environmental stability, IDV has the potential to further gain virulence or even infect humans. An efficacious vaccine is needed to prevent infection and stop potential cross-species transmission. In this study, we designed a DNA vaccine encoding the consensus hemagglutinin-esterase fusion (HEF) protein of two lineages of IDV (D/OK and D/660) and tested its efficacy in a guinea pig model. Our results showed that the consensus DNA vaccine elicited high-titer neutralizing antibodies and achieved sterilizing protection against two lineage-representative IDV intranasal infections. To our knowledge, this is the first study showing that a DNA vaccine expressing consensus HEF is efficacious in preventing different lineages of IDV infections.

Induction of Broadly Cross-Reactive Stalk-Specific Antibody Responses to Influenza Group 1 and Group 2 Hemagglutinins by Natural H7N9 Virus Infection in Humans.

Background: The outbreak of novel avian H7N9 influenza virus infections in China in 2013 has demonstrated the continuing threat posed by zoonotic pathogens. Deciphering the immune response during natural infection will guide future vaccine development. Methods: We assessed the induction of heterosubtypic cross-reactive antibodies induced by H7N9 infection against a large panel of recombinant hemagglutinins and neuraminidases by quantitative enzyme-linked immunosorbent assay, and novel chimeric hemagglutinin constructs were used to dissect the anti-stalk or -head humoral immune response. Results: H7N9 infection induced strong antibody responses against divergent H7 hemagglutinins. Interestingly, we also found induction of antibodies against heterosubtypic hemagglutinins from both group 1 and group 2 and a boost in heterosubtypic neutralizing activity in the absence of hemagglutination inhibitory activity. Kinetic monitoring revealed that heterosubtypic binding/neutralizing antibody responses typically appeared and peaked earlier than intrasubtypic responses, likely mediated by memory recall responses. Conclusions: Our results indicate that cross-group binding and neutralizing antibody responses primarily targeting the stalk region can be elicited after natural influenza virus infection. These data support our understanding of the breadth of the postinfection immune response that could inform the design of future, broadly protective influenza virus vaccines.

Next-Generation mRNA Sequencing Reveals Pyroptosis-Induced CD4+ T Cell Death in Early Simian Immunodeficiency Virus-Infected Lymphoid Tissues.

UNLABELLED: Lymphoid tissues (LTs) are the principal sites where human immunodeficiency virus type 1 (HIV-1) replicates and virus-host interactions take place, resulting in immunopathology in the form of inflammation, immune activation, and CD4(+) T cell death. The HIV-1 pathogenesis in LTs has been extensively studied; however, our understanding of the virus-host interactions in the very early stages of infection remains incomplete. We investigated virus-host interactions in the rectal draining lymph nodes (dLNs) of rhesus macaques at different times after intrarectal inoculation (days postinoculation [dpi]) with simian immunodeficiency virus (SIV). At 3 dpi, 103 differentially expressed genes (DEGs) were detected using next-generation mRNA sequencing (RNA-seq). At 6 and 10 dpi, concomitant with increased SIV replication, 366 and 1,350 DEGs were detected, respectively, including upregulation of genes encoding proteins that play a role in innate antiviral immune responses, inflammation, and immune activation. Notably, genes (IFI16, caspase-1, and interleukin 1ß [IL-1ß]) in the canonical pyroptosis pathway were significantly upregulated in expression. We further validated increased pyroptosis using flow cytometry and found that the number of CD4(+) T cells expressing activated caspase-1 protein, the hallmark of ongoing pyroptosis, were significantly increased, which is correlated with decreased CD4(+) T cells in dLNs. Our results demonstrated that pyroptosis contributes to the CD4(+) T cell death in vivo in early SIV infection, which suggests that pyroptosis may play a pivotal role in the pathogenesis of SIV, and by extension, that of HIV-1, since pyroptosis not only induces CD4(+) T cell death but also amplifies inflammation and immune activation. Thus, blocking CD4(+) T cell pyroptosis could be a complementary treatment to antiretroviral therapy. IMPORTANCE: Although secondary lymphoid tissues (LTs) are principal sites of human immunodeficiency virus type 1 (HIV-1) replication, inflammation, immune activation, and CD4(+) T cell death, immunopathogenesis in LTs during early infection remains largely unknown. Using the simian immunodeficiency virus (SIV)/rhesus monkey model of HIV rectal infection, we investigated early virus-host interactions. Our results revealed elevated potent host responses in early infection in LTs, including upregulation of genes involved in antiviral immune response, inflammation, and immune activation. Importantly, genes involved in the canonical pyroptosis pathway were significantly upregulated, and there was a strong correlation between CD4(+) T cell decrease and increased number of CD4(+) T cells expressing activated caspase-1 protein, demonstrating that pyroptosis contributes to CD4(+) T cell death in vivo in very early SIV infection. Our finding suggests that blocking pyroptosis may be able to decrease CD4(+) T cell loss during early SIV infection.

Early hypercytokinemia is associated with interferon-induced transmembrane protein-3 dysfunction and predictive of fatal H7N9 infection.

A unique avian-origin A/H7N9 influenza virus has so far caused 134 cases with 44 deaths. Probing the host factors contributing to disease severity, we found that lower levels of plasma inflammatory cytokines on hospital admission correlated with faster recovery in 18 patients with A/H7N9 influenza virus, whereas high concentrations of (in particular) IL-6, IL-8, and macrophage inflammatory protein-1ß were predictive of a less favorable or fatal outcome. Analysis of bronchoalveolar lavage samples showed up to 1,000-fold greater cytokine/chemokine levels relative to plasma. Furthermore, patients with the rs12252-C/C IFN-induced transmembrane protein-3 (IFITM3) genotype had more rapid disease progression and were less likely to survive. Compared with patients with the rs12252-T/T or rs12252-T/C genotype of IFITM3, patients with the C/C genotype had a shorter time from disease onset to the time point when they sought medical aid (hospital admission or antiviral therapy) and a shorter interval to development of the acute respiratory distress syndrome stage (reflected by shorter intervals between clinical onset and methylprednisolone treatments and higher rates of mechanical ventilator use), as well as experiencing elevated/prolonged lung virus titers and cytokine production and higher mortality. The present analysis provides reported data on the H7N9 influenza-induced "cytokine storm" at the site of infection in humans and identifies the rs12252-C genotype that compromises IFITM3 function as a primary genetic correlate of severe H7N9 pneumonia. Together with rs12252 sequencing, early monitoring of plasma cytokines is thus of prognostic value for the treatment and management of severe influenza pneumonia.

Boosting functional avidity of CD8+ T cells by vaccinia virus vaccination depends on intrinsic T-cell MyD88 expression but not the inflammatory milieu.

UNLABELLED: T-cell functional avidity is a crucial determinant for efficient pathogen clearance. Although recombinant DNA priming coupled with a vaccinia-vectored vaccine (VACV) boost has been widely used to mount robust CD8+ T-cell responses, how VACV boost shapes the properties of memory CD8+ T cells remains poorly defined. Here, we characterize the memory CD8+ T cells boosted by VACV and demonstrate that the intrinsic expression of MyD88 is critical for their high functional avidity. Independent of selection of clones with high-affinity T-cell receptor (TCR) or of enhanced proximal TCR signaling, the VACV boost significantly increased T-cell functional avidity through a decrease in the activation threshold. VACV-induced inflammatory milieu is not sufficient for this improvement, as simultaneous administration of the DNA vaccine and mock VACV had no effects on the functional avidity of memory CD8+ T cells. Furthermore, reciprocal adoptive transfer models revealed that the intrinsic MyD88 pathway is required for instructing the functional avidity of CD8+ T cells boosted by VACV. Taking these results together, the intrinsic MyD88 pathway is required for the high functional avidity of VACV-boosted CD8+ T cells independent of TCR selection or the VACV infection-induced MyD88-mediated inflammatory milieu. IMPORTANCE: Functional avidity is one of the crucial determinants of T-cell functionality. Interestingly, although it has been demonstrated that a DNA prime-VACV boost regimen elicits high levels of T-cell functional avidity, how VACV changes the low avidity of CD8+ T cells primed by DNA into higher ones in vivo is less defined. Here, we proved that the enhancement of CD8+ T cell avidity induced by VACV boost is mediated by the intrinsic MyD88 pathway but not the MyD88-mediated inflammatory milieu, which might provide prompts in vaccine design.

A biphenotypic lymphocyte subset displays both T- and B-cell functionalities.

T cell/B cell mixed phenotypic lymphocytes have been observed in different disease contexts, yet their presence and function in physiological conditions remain elusive. Here, we provide evidence for the existence of a lymphocyte subset endogenously expressing both T- and B-cell lineage markers in mice. The majority of these T/B phenotypic lymphocytes (CD3+CD19+) show an origin of pro/pre B cells and distribute widely in mouse bone marrow, lymph nodes, spleen, and peripheral blood. Functional assays show that these biphenotypic lymphocytes can be activated through stimulating TCR or BCR signaling pathways. Moreover, we show that these cells actively participate both the humoral and cellular immune responses elicited by vaccination. Compared to conventional T cells, these biphenotypic lymphocytes can secrete a higher level of IL-2 but a lower level of TNF-α upon antigen specific stimulation. An equivalent lymphocyte subset is found in freshly isolated human PBMCs and exhibits similar functionality, albeit at a lower frequency than in mice.

The Critical Role of the Shroom Family Proteins in Morphogenesis, Organogenesis and Disease.

The Shroom (Shrm) family of actin-binding proteins has a unique and highly conserved Apx/Shrm Domain 2 (ASD2) motif. Shroom protein directs the subcellular localization of Rho-associated kinase (ROCK), which remodels the actomyosin cytoskeleton and changes cellular morphology via its ability to phosphorylate and activate non-muscle myosin II. Therefore, the Shrm-ROCK complex is critical for the cellular shape and the development of many tissues, including the neural tube, eye, intestines, heart, and vasculature system. Importantly, the structure and expression of Shrm proteins are also associated with neural tube defects, chronic kidney disease, metastasis of carcinoma, and X-link mental retardation. Therefore, a better understanding of Shrm-mediated signaling transduction pathways is essential for the development of new therapeutic strategies to minimize damage resulting in abnormal Shrm proteins. This paper provides a comprehensive overview of the various Shrm proteins and their roles in morphogenesis and disease.

Safe pseudovirus-based assay for neutralization antibodies against influenza A(H7N9) virus.

Serologic studies are urgently needed to assist in understanding an outbreak of influenza A(H7N9) virus. However, a biosafety level 3 laboratory is required for conventional serologic assays with live lethal virus. We describe a safe pseudovirus-based neutralization assay with preliminary assessment using subtype H7N9-infected samples and controls.

The impacts of vaccination status and host factors during early infection on SARS-CoV-2 persistence:a retrospective single-center cohort study.

BACKGROUND: Viral persistence is a crucial factor that influences the transmissibility of SARS-CoV-2. However, the impacts of vaccination and physiological variables on viral persistence have not been adequately clarified. METHODS: We collected the clinical records of 377 COVID-19 patients, which contained unvaccinated patients and patients received two doses of an inactivated vaccine or an mRNA vaccine. The impacts of vaccination on disease severity and viral persistence and the correlations between 49 laboratory variables and viral persistence were analyzed separately. Finally, we established a multivariate regression model to predict the persistence of viral RNA. RESULTS: Both inactivated and mRNA vaccines significantly reduced the rate of moderate cases, while the vaccine related shortening of viral RNA persistence was only observed in moderate patients. Correlation analysis showed that 10 significant laboratory variables were shared by the unvaccinated mild patients and mild patients inoculated with an inactivated vaccine, but not by the mild patients inoculated with an mRNA vaccine. A multivariate regression model established based on the variables correlating with viral persistence in unvaccinated mild patients could predict the persistence of viral RNA for all patients except three moderate patients inoculated with an mRNA vaccine. CONCLUSION: Vaccination contributed limitedly to the clearance of viral RNA in COVID-19 patients. While, laboratory variables in early infection could predict the persistence of viral RNA.

Impaired long-term anti-HBs responses in choronic hepatitis C patients: Results from a five-year follow-up study with healthy control.

Although hepatitis B virus (HBV) vaccination is recommended for hepatitis C virus (HCV)-infected individuals to avoid HBV superinfection, the persistence of their humoral and cell-mediated immunity responses to HBV vaccination is still under investigation. Patients with chronic hepatitis C (CHC) and matched healthy controls, who completed three doses of hepatitis B vaccine (HepB) in 2014, were followed up five years later. One booster dose of HepB was given to those with antibody against hepatitis B surface antigen (anti-HBs) lower than 10mIU/mL. Anti-HBs was tested at follow-up and on the 14th day after the booster dose, as well as HBsAg specific spot-forming cells of interferon γ and interleukin (IL) 2, 4, 5, and 6. At five years, only 56.58% of the CHC patients had sero-protective titers (≥10mIU/mL) of anti-HBs, compared to 70.83% in the controls (P < .05). Similarly, the geometric mean concentration (GMC) of anti-HBs in CHC patients was significantly lower than that in controls (16.95 vs 37.34 mIU/mL, P < .05). After the booster, both GMC and the rate of anamnestic response increased to a very high level in the two groups and the difference between them disappeared (P > .05). Multivariable analysis showed that HCV infection was an independent predictor factor to anti-HBs level at follow-up. HBsAg specific IL-6 was stronger in the CHC patients compared to the controls (P < .05). The data indicate that the durability of protective anti-HBs is poorer in CHC patients compared to healthy individuals, and impaired long-term anti-HBs responses might be associated with the increased HBsAg specific IL-6 responses.

The average IFN-γ secreting capacity of specific CD8(+) T cells is compromised while increasing copies of a single T cell epitope encoded by DNA vaccine.

Previous studies suggested that both the frequency and the mean fluorescence intensity (MFI) of cytokine secreting T cells could be of great value for immunogenicity evaluation of a vaccine. In this study, by constructing epitope-based DNA vaccines encoding a previously identified CD8(+) T cell epitope, we investigated the influence of multiplying epitope copies on both the frequency and the MFI of specific IFN-γ secreting CD8(+) T cells. We found that frequencies of specific CD8(+) T cell could be improved by multiplying epitope copies, while the MFI of IFN-γ secreted by epitope-specific CD8(+) T cells decreased synchronously. And further analysis showed that the decrease of MFI was not caused by the functional avidity variation of CD8(+) T cell receptor.