Pathogenesis and virulence of coronavirus disease: Comparative pathology of animal models for COVID-19.

Animal models that can replicate clinical and pathologic features of severe human coronavirus infections have been instrumental in the development of novel vaccines and therapeutics. The goal of this review is to summarize our current understanding of the pathogenesis of coronavirus disease 2019 (COVID-19) and the pathologic features that can be observed in several currently available animal models. Knowledge gained from studying these animal models of SARS-CoV-2 infection can help inform appropriate model selection for disease modelling as well as for vaccine and therapeutic developments.

Assessment of chemotherapy resistance changes in human colorectal cancer xenografts in rats based on MRI histogram features.

Purpose: We investigated the value of magnetic resonance imaging (MRI) histogram features, a non-invasive method, in assessing the changes in chemoresistance of colorectal cancer xenografts in rats. Methods: A total of 50 tumor-bearing mice with colorectal cancer were randomly divided into two groups: control group and 5-fluorouracil (5-FU) group. The MRI histogram characteristics and the expression levels of p53 protein and MRP1 were obtained at 24 h, 48 h, 72 h, 120 h, and 168 h after treatment. Results: Sixty highly repeatable MRI histogram features were obtained. There were 16 MRI histogram parameters and MRP1 resistance protein differences between groups. At 24 h after treatment, the MRI histogram texture parameters of T2-weighted imaging (T2WI) images (10%, 90%, median, energy, and RootMeanSquared) and D images (10% and Range) were positively correlated with MRP1 (r = 0.925, p = 0.005). At 48 h after treatment, histogram texture parameters of apparent diffusion coefficient (ADC) images (Energy) were positively correlated with the presence of MRP1 resistance protein (r = 0.900, p = 0.037). There was no statistically significant difference between MRI histogram features and p53 protein expression level. Conclusions: MRI histogram texture parameters based on T2WI, D, and ADC maps can help to predict the change of 5-FU resistance in colorectal cancer in the early stage and provide important reference significance for clinical treatment.

Vegetation net primary productivity in urban areas of China responded positively to the COVID-19 lockdown in spring 2020.

To prevent the spread of COVID-19, China implemented large-scale lockdown measures in early 2020, resulting in a marked reduction in human activities over a short period. Studies have explored environmental changes during lockdowns, lacking analysis of response of net primary productivity (NPP) to lockdowns, especially for diverse vegetation types. Correlation between NPP and impact factors during lockdowns remains unclear. Through Google Earth Engine, we evaluated spatial-temporal changes in spring NPP at multiple scales during lockdown period (LD, 2020) compared with unlocked period (UL, 2017-2019) by remote sensing data in urban areas of China. Changes in four impact factors, aerosol optical depth (AOD) and photosynthetically active radiation (PAR) (via remote sensing data), alongside temperature (TEM) and precipitation (PRE) (via meteorological data) were explored. Additionally, geodetector, a valuable statistical tool for detecting the driving ability of various elements, was employed to explore the underlying causes of vegetation changes during LD. In the spring of LD: 1) National urban NPP generally increased (+6.50 %), notably in Northeast China (NE), North China (N) and East China (E). Besides, overall urban AOD decreased (-3.64 %), notably in N and Central China (C). National urban PAR increased (+2.7 %), particularly in C and Northwest China (NW). However, overall urban TEM (-0.06 %) and PRE (-1.21 %) changed negatively. 2) NPP in all three vegetation types in urban areas enhanced, with change rates: croplands > forests > grasslands. Evident enhancements occurred in the forests and croplands in N, and the grasslands in NE. 3) Through geodetector, during LD, AOD (q = 0.223) and TEM (q = 0.272) emerged as the dominant factors for NPP. Compared with UL, the explanatory power of AOD and PAR on NPP increased during LD. This study provides valuable insights into understanding the effects of short-term human activities on vegetation productivity, offering reference for the formulation of ecological and environmental policies.

Assessment of Immune Responses to a Trivalent Pichinde Virus-Vectored Vaccine Expressing Hemagglutinin Genes from Three Co-Circulating Influenza A Virus Subtypes in Pigs.

Pichinde virus (PICV) can infect several animal species and has been developed as a safe and effective vaccine vector. Our previous study showed that pigs vaccinated with a recombinant PICV-vectored vaccine expressing the hemagglutinin (HA) gene of an H3N2 influenza A virus of swine (IAV-S) developed virus-neutralizing antibodies and were protected against infection by the homologous H3N2 strain. The objective of the current study was to evaluate the immunogenicity and protective efficacy of a trivalent PICV-vectored vaccine expressing HA antigens from the three co-circulating IAV-S subtypes: H1N1, H1N2, and H3N2. Pigs immunized with the trivalent PICV vaccine developed virus-neutralizing (VN) and hemagglutination inhibition (HI) antibodies against all three matching IAV-S. Following challenge infection with the H1N1 strain, five of the six pigs vaccinated with the trivalent vaccine had no evidence of IAV-S RNA genomes in nasal swabs and bronchoalveolar lavage fluid, while all non-vaccinated control pigs showed high number of copies of IAV-S genomic RNA in these two types of samples. Overall, our results demonstrate that the trivalent PICV-vectored vaccine elicits antibody responses against the three targeted IAV-S strains and provides protection against homologous virus challenges in pigs. Therefore, PICV exhibits the potential to be explored as a viral vector for delivering multiple vaccine antigens in swine.

A Comparative Assessment of Different Aerogel-Insulated Building Walls for Enhanced Thermal Insulation Performance.

Aerogel is widely recognized as a superinsulating material with great potential for enhancing the thermal insulation performance of building walls. It can be applied in various forms such as aerogel plasters (AP), aerogel fibrous composites (AFC), and aerogel concrete (AC) in practical engineering applications. This study aims to investigate the most efficient application form for maximizing building insulation performance while minimizing the amount of aerogel used. To predict the thermal insulation performance of aerogel-insulated walls, a resistance-capacitance network model integrating the aerogels' effective thermal conductivity model was developed and was validated by comparing it with Fluent simulation software results in terms of surface temperature. Using the validated models, the thermophysical parameters, transient thermal properties, and transmission load were predicted and compared among AP, AFC, and AC walls. The results indicate that using AFC can result in approximately 50% cost savings to achieve the same thermal resistance. After adding a 20 mm thickness of aerogel to the reference wall without aerogel, the AFC wall exhibited the highest improvement in thermal insulation performance, reaching 46.0-53.5%, followed by the AP wall, and then the AC wall, aligning with considerations of microstructural perspectives, thermal resistance distributions, and thermal non-uniformity factors. Therefore, giving priority to AFC use could reduce the required amount of silica aerogel and enhance economic efficiency. These results provide valuable insights for theoretical models and the application of aerogel-insulated walls in building engineering insulation.

Enhancing anti-viral neutralization response to immunization with HIV-1 envelope glycoprotein immunogens.

An effective human immunodeficiency virus type I (HIV-1) vaccine that robustly elicits broadly neutralizing antibodies (bnAbs) against HIV-1 envelope glycoproteins (Envs) to block viral entry is still not available. Thus, identifying triggers for elicitation of different types of anti-HIV-1 Env antibodies by vaccination could provide further guidance for immunogen design and vaccine development. Here, we studied the immune response to HIV-1 Env immunogens in rabbits. We show that sequential immunizations with conformation-specific Env immunogens can elicit low titer but broad neutralization responses against heterologous, neutralization-resistant (tier 2/3) transmitted/founder (T/F) HIV-1 strains. More importantly, an mRNA vaccine candidate that could mediate the presentation of a cytoplasmic tail-deleted (ΔCT) HIV-1AD8 Env immunogen on virus-like particles significantly increased the neutralization response. This strategy shifted the type of elicited antibodies, decreasing the level of binding to soluble Envs while significantly increasing their overall viral neutralization activity. The breadth and potency of neutralizing response against heterologous, T/F HIV-1 strains significantly increased in a subset of rabbits. Efficient neutralization activity was associated with high cellular immune responses specific to HIV-1 Envs. These results help to understand the immune response to different immunization schemes and will allow developing new approaches to selectively manipulate the type of humoral immune response by specific vaccination.

Mitochondria-targeted fluorophores for in vivo NIR-II imaging-guided PDT/PTT.

A simple yet powerful D-A type-based NIR-II fluorophore (MTF) with mitochondria targeting was constructed. This mitochondrial targeting dye MTF exhibited not only a photothermal effect but also photodynamic performance, and was further fabricated with DSPE-mPEG to generate nanodots for in vivo experiments, achieving strong NIR-II fluorescence tracing of tumors and impressive NIR-II image-guided photodynamic therapy (PDT) and photothermal therapy (PTT).

Pathogenicity and virulence of influenza.

Influenza viruses, including four major types (A, B, C, and D), can cause mild-to-severe and lethal diseases in humans and animals. Influenza viruses evolve rapidly through antigenic drift (mutation) and shift (reassortment of the segmented viral genome). New variants, strains, and subtypes have emerged frequently, causing epidemic, zoonotic, and pandemic infections, despite currently available vaccines and antiviral drugs. In recent years, avian influenza viruses, such as H5 and H7 subtypes, have caused hundreds to thousands of zoonotic infections in humans with high case fatality rates. The likelihood of these animal influenza viruses acquiring airborne transmission in humans through viral evolution poses great concern for the next pandemic. Severe influenza viral disease is caused by both direct viral cytopathic effects and exacerbated host immune response against high viral loads. Studies have identified various mutations in viral genes that increase viral replication and transmission, alter tissue tropism or species specificity, and evade antivirals or pre-existing immunity. Significant progress has also been made in identifying and characterizing the host components that mediate antiviral responses, pro-viral functions, or immunopathogenesis following influenza viral infections. This review summarizes the current knowledge on viral determinants of influenza virulence and pathogenicity, protective and immunopathogenic aspects of host innate and adaptive immune responses, and antiviral and pro-viral roles of host factors and cellular signalling pathways. Understanding the molecular mechanisms of viral virulence factors and virus-host interactions is critical for the development of preventive and therapeutic measures against influenza diseases.

Fine mapping of a QTL and identification of candidate genes associated with cold tolerance during germination in peanut (Arachis hypogaea L.) on chromosome B09 using whole genome re-sequencing.

Low temperatures significantly affect the growth and yield of peanuts. Temperatures lower than 12 °C are generally detrimental for the germination of peanuts. To date, there has been no report on precise information on the quantitative trait loci (QTL) for cold tolerance during the germination in peanuts. In this study, we developed a recombinant inbred line (RIL) population comprising 807 RILs by tolerant and sensitive parents. Phenotypic frequencies of germination rate low-temperature conditions among RIL population showed normally distributed in five environments. Then, we constructed a high density SNP-based genetic linkage map through whole genome re-sequencing (WGRS) technique and identified a major quantitative trait locus (QTL), qRGRB09, on chromosome B09. The cold tolerance-related QTLs were repeatedly detected in all five environments, and the genetic distance was 6.01 cM (46.74 cM - 61.75 cM) after taking a union set. To further confirm that qRGRB09 was located on chromosome B09, we developed Kompetitive Allele Specific PCR (KASP) markers for the corresponding QTL regions. A regional QTL mapping analysis, which was conducted after taking the intersection of QTL intervals of all environments into account, confirmed that qRGRB09 was between the KASP markers, G22096 and G220967 (chrB09:155637831-155854093), and this region was 216.26 kb in size, wherein a total of 15 annotated genes were detected. This study illustrates the relevance of WGRS-based genetic maps for QTL mapping and KASP genotyping that facilitated QTL fine mapping of peanuts. The results of our study also provided useful information on the genetic architecture underlying cold tolerance during germination in peanuts, which in turn may be useful for those engaged in molecular studies as well as crop improvement in the cold-stressed environment.

Recombinant Pichinde viral vector expressing tuberculosis antigens elicits strong T cell responses and protection in mice.

Introduction: Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) remains a major global health threat. The only available vaccine Bacille Calmette-Guérin (BCG) does not prevent adult pulmonary TB. New effective TB vaccines should aim to stimulate robust T cell responses in the lung mucosa to achieve high protective efficacy. We have previously developed a novel viral vaccine vector based on recombinant Pichinde virus (PICV), a non-pathogenic arenavirus with low seroprevalence in humans, and have demonstrated its efficacy to induce strong vaccine immunity with undetectable anti-vector neutralization activity. Methods: Using this tri-segmented PICV vector (rP18tri), we have generated viral vectored TB vaccines (TBvac-1, TBvac-2, and TBvac-10) encoding several known TB immunogens (Ag85B, EsxH, and ESAT-6/EsxA). A P2A linker sequence was used to allow for the expression of two proteins from one open-reading-frame (ORF) on the viral RNA segments. The immunogenicity of TBvac-2 and TBvac-10 and the protective efficacy of TBvac-1 and TBvac-2 were evaluated in mice. Results: Both viral vectored vaccines elicited strong antigen-specific CD4 and CD8 T cells through intramuscular (IM) and intranasal (IN) routes as evaluated by MHC-I and MHC-II tetramer analyses, respectively. The IN inoculation route helped to elicit strong lung T cell responses. The vaccine-induced antigen-specific CD4 T cells are functional, expressing multiple cytokines as detected by intracellular cytokine staining. Finally, immunization with TBvac-1 or TBvac-2, both expressing the same trivalent antigens (Ag85B, EsxH, ESAT6/EsxA), reduced Mtb lung tissue burden and dissemination in an aerosol challenge mouse model. Conclusions: The novel PICV vector-based TB vaccine candidates can express more than two antigens via the use of P2A linker sequence and elicit strong systemic and lung T cell immunity with protective efficacy. Our study suggests the PICV vector as an attractive vaccine platform for the development of new and effective TB vaccine candidates.

Comparative Pathology of Animal Models for Influenza A Virus Infection.

Animal models are essential for studying disease pathogenesis and to test the efficacy and safety of new vaccines and therapeutics. For most diseases, there is no single model that can recapitulate all features of the human condition, so it is vital to understand the advantages and disadvantages of each. The purpose of this review is to describe popular comparative animal models, including mice, ferrets, hamsters, and non-human primates (NHPs), that are being used to study clinical and pathological changes caused by influenza A virus infection with the aim to aid in appropriate model selection for disease modeling.

Case report: A novel heterozygous synonymous variant in deep exon region of NIPBL gene generating a non-canonical splice donor in a patient with cornelia de lange syndrome.

Cornelia de Lange syndrome (CdLS) is an autosomal dominant or X-linked genetic disease with significant genetic heterogeneity. Variants of the NIPBL gene are responsible for CdLS in 60% of patients. Herein, we report the case of a patient with CdLS showing distinctive facial features, microcephaly, developmental delay, and growth retardation. Whole exome sequencing was performed for the patient, and a novel de novo heterozygous synonymous variant was identified in the deep region of exon 40 in the NIPBL gene (NM_133433.4: c. 6819G > T, p. Gly2273 = ). The clinical significance of the variant was uncertain according to the ACMG/AMP guidelines; however, based on in silico analysis, it was predicted to alter mRNA splicing. To validate the prediction, a reverse transcriptase-polymerase chain reaction was conducted. The variant activated a cryptic splice donor, generating a short transcript of NIPBL. A loss of 137 bp at the 3' end of NIPBL exon 40 was detected, which potentially altered the open reading frame by inserting multiple premature termination codons. Quantitative real-time PCR analysis showed that the ratio of the transcription level of the full-length transcript to that of the altered short transcript in the patient was 5:1, instead of 1:1. These findings may explain the relatively mild phenotype of the patient, regardless of the loss of function of the truncated protein due to a frameshift in the mRNA. To the best of our knowledge, this study is the first to report a synonymous variant in the deep exon regions of the NIPBL gene responsible for CdLS. The identified variant expands the mutational spectrum of the NIPBL gene. Furthermore, synonymous variations may be pathogenic, which should not be ignored in the clinical and genetic diagnosis of the disease.

Chaotic Mapping-Based Anti-Sorting Radio Frequency Stealth Signals and Compressed Sensing-Based Echo Signal Processing Technology.

Radio frequency (RF) stealth anti-sorting technology can improve the battlefield survival rate of radar and is one of the research hotspots in the radar field. In this study, the signal design principle of anti-sequential difference histogram (SDIF) sorting was explored for the main sorting algorithm of the SDIF. Furthermore, we designed a piecewise linear chaotic system with interval number parameterization based on random disturbance and proposed a method to modulate the repetition period of widely spaced signal pulses using a chaotic system. Then, considering the difficulty of the traditional signal processing method to measure the velocity of the highly random anti-sorting signals designed in this paper, we used compressed sensing (CS) technology to process the echoes of the signals to solve the velocity and distance of the detection targets. Finally, simulation verification was performed from the correctness of the signal design principle, the performance of the chaotic system, the anti-sorting performance of the designed signals and the recovery and reconstruction performance of the signals by CS. The results show that: (a) the signal design principle presented in this paper can guide the signal design correctly; (b) the performance of the piecewise linear chaotic system with interval number parameterization is better than that of the classical one-dimensional chaotic system; (c) the anti-sorting signal modulated by the chaotic system can achieve anti-SDIF sorting, and the anti-sorting signals designed in this paper can be processed to obtain the velocity and distance of the targets.

Development and validation of a prognostic nomogram for predicting cancer-specific survival in patients with metastatic clear cell renal carcinoma: A study based on SEER database.

Objectives: Clear cell renal cell carcinoma (ccRCC) is highly prevalent, prone to metastasis, and has a poor prognosis after metastasis. Therefore, this study aimed to develop a prognostic model to predict the individualized prognosis of patients with metastatic clear cell renal cell carcinoma (mccRCC). Patients and Methods: Data of 1790 patients with mccRCC, registered from 2010 to 2015, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. The included patients were randomly divided into a training set (n = 1253) and a validation set (n = 537) based on the ratio of 7:3. The univariate and multivariate Cox regression analyses were used to identify the important independent prognostic factors. A nomogram was then constructed to predict cancer specific survival (CSS). The performance of the nomogram was internally validated by using the concordance index (C-index), calibration plots, receiver operating characteristic curves, net reclassification improvement (NRI), integrated discrimination improvement (IDI), and decision curve analysis (DCA). We compared the nomogram with the TNM staging system. Kaplan-Meier survival analysis was applied to validate the application of the risk stratification system. Results: Diagnostic age, T-stage, N-stage, bone metastases, brain metastases, liver metastases, lung metastases, chemotherapy, radiotherapy, surgery, and histological grade were identified as independent predictors of CSS. The C-index of training and validation sets are 0.707 and 0.650 respectively. In the training set, the AUC of CSS predicted by nomogram in patients with mccRCC at 1-, 3- and 5-years were 0.770, 0.758, and 0.757, respectively. And that in the validation set were 0.717, 0.700, and 0.700 respectively. Calibration plots also showed great prediction accuracy. Compared with the TNM staging system, NRI and IDI results showed that the predictive ability of the nomogram was greatly improved, and DCA showed that patients obtained clinical benefits. The risk stratification system can significantly distinguish the patients with different survival risks. Conclusion: In this study, we developed and validated a nomogram to predict the CSS rate in patients with mccRCC. It showed consistent reliability and clinical applicability. Nomogram may assist clinicians in evaluating the risk factors of patients and formulating an optimal individualized treatment strategy.

Absolute decrease in regulatory T cells and low-dose interleukin-2 therapy: restoring and expanding regulatory T cells to treat systemic sclerosis: a 24-week study.

BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular lesions, immunological alterations and tissue fibrosis. There is some evidence of an imbalance between T-cell subsets in this disease. Interleukin (IL)-2 is a cytokine that can regulate the activity of immune cells and there is evidence that low-dose IL-2 therapy can be used to treat immune diseases. AIM: To investigate the changes of peripheral lymphocyte subsets, especially T helper (Th)17 and regulatory T (Treg) cells and the effects of low-dose IL-2 therapy in patients with SSc. METHODS: In total, 66 patients with SSc and 49 sex- and age-matched healthy controls (HCs), were enrolled. The absolute numbers of peripheral lymphocyte subsets in these individuals were determined by flow cytometry. The 66 patients, were divided into 2 groups: 23 (the IL-2 group) were treated with low-dose (5.0 × 105 IU) IL-2 by subcutaneous injection daily for 5 days combined with conventional therapy, while the remaining 23 patients received conventional therapy only. RESULTS: Compared with HCs, the absolute numbers of peripheral T, CD4+ T, CD8+ T, natural killer and Treg cells were significantly lower in patients with SSc, with the most dramatic difference seen in both the absolute number and percentage of Treg cells in these patients, including new (previously untreated) cases, resulting in an imbalance (elevated ratio) between Th17 and Treg cells. At Week 24 after commencement of IL-2 treatment, Treg cells were markedly increased and tended to restore the balance of Th17 to Treg cells compared with baseline. Erythrocyte sedimentation rate, C-reactive protein, modified Rodnan Skin Score and visual analogue scale score were significantly decreased in both the IL-2 and non-IL-2 groups, indicating disease improvement. Notably, compared with those in the non-IL-2 group, patients treated with IL-2 had greater improvement. CONCLUSION: Our study showed that the absolute numbers of peripheral Treg cells together with total T, CD4+ T, CD8+ T and NK is significantly decreased, leading to an imbalance of Th17 to Treg cells in patients with SSc, and that low-dose IL-2 treatment could restore the balance of the two immune cells and reduce disease activity without obvious adverse effects.

Design of Multi-Parameter Compound Modulated RF Stealth Anti-Sorting Signals Based on Hyperchaotic Interleaving Feedback.

Radio frequency (RF) stealth anti-sorting technology is a research hotspot in the radar field. In this study, the signal design principles of anti-cluster and anti-SDIF sorting were investigated for processes of clustering pre-sorting and sequence-difference-histogram main sorting. Then, in accordance with the signal design principle, a 2D interleaving feedback hyperchaotic system based on the cosine-exponential was designed. A method to modulate the pulse repetition interval (PRI) of the signal parameters and carrier frequency with wide intervals through the hyperchaotic system was developed. Finally, we verified the correctness of the signal design principle, the performance of the hyperchaotic system, and the anti-sorting performance of the designed signal using simulations. The results showed that the signal design principle could guide the signal design. The hyperchaotic system outperformed the classical 1D and 2D chaotic systems and the classical 3D Lorenz systems in terms of randomness and complexity. Anti-cluster sorting and anti-SDIF sorting could be realized by anti-sorting signals modulated by a hyperchaotic system, with the anti-SDIF sorting performance being better than that of the PRI random jitter signal.

Influenza A virus activates cellular Tropomyosin receptor kinase A (TrkA) signaling to promote viral replication and lung inflammation.

Influenza A virus (IAV) infection causes acute respiratory disease with potential severe and deadly complications. Viral pathogenesis is not only due to the direct cytopathic effect of viral infections but also to the exacerbated host inflammatory responses. Influenza viral infection can activate various host signaling pathways that function to activate or inhibit viral replication. Our previous studies have shown that a receptor tyrosine kinase TrkA plays an important role in the replication of influenza viruses in vitro, but its biological roles and functional mechanisms in influenza viral infection have not been characterized. Here we show that IAV infection strongly activates TrkA in vitro and in vivo. Using a chemical-genetic approach to specifically control TrkA kinase activity through a small molecule compound 1NMPP1 in a TrkA knock-in (TrkA KI) mouse model, we show that 1NMPP1-mediated TrkA inhibition completely protected mice from a lethal IAV infection by significantly reducing viral loads and lung inflammation. Using primary lung cells isolated from the TrkA KI mice, we show that specific TrkA inhibition reduced IAV viral RNA synthesis in airway epithelial cells (AECs) but not in alveolar macrophages (AMs). Transcriptomic analysis confirmed the cell-type-specific role of TrkA in viral RNA synthesis, and identified distinct gene expression patterns under the TrkA regulation in IAV-infected AECs and AMs. Among the TrkA-activated targets are various proinflammatory cytokines and chemokines such as IL6, IL-1ß, IFNs, CCL-5, and CXCL9, supporting the role of TrkA in mediating lung inflammation. Indeed, while TrkA inhibitor 1NMPP1 administered after the peak of IAV replication had no effect on viral load, it was able to decrease lung inflammation and provided partial protection in mice. Taken together, our results have demonstrated for the first time an important biological role of TrkA signaling in IAV infection, identified its cell-type-specific contribution to viral replication, and revealed its functional mechanism in virus-induced lung inflammation. This study suggests TrkA as a novel host target for therapeutic development against influenza viral disease.

Immunogenicity and Protective Efficacy of a Recombinant Pichinde Viral-Vectored Vaccine Expressing Influenza Virus Hemagglutinin Antigen in Pigs.

Influenza A virus of swine (IAV-S) is an economically important swine pathogen. The IAV-S hemagglutinin (HA) surface protein is the main target for vaccine development. In this study, we evaluated the feasibility of using the recombinant tri-segmented Pichinde virus (rPICV) as a viral vector to deliver HA antigen to protect pigs against IAV-S challenge. Four groups of weaned pigs (T01-T04) were included in the study. T01 was injected with PBS to serve as a non-vaccinated control. T02 was inoculated with rPICV expressing green fluorescence protein (rPICV-GFP). T03 was vaccinated with rPICV expressing the HA antigen of the IAV-S H3N2 strain (rPICV-H3). T04 was vaccinated with the recombinant HA protein antigen of the same H3N2 strain. Pigs were vaccinated twice at day 0 and day 21 and challenged at day 43 by intra-tracheal inoculation with the homologous H3N2 IAV-S strain. After vaccination, all pigs in T03 and T04 groups were seroconverted and exhibited high titers of plasma neutralizing antibodies. After challenge, high levels of IAV-S RNA were detected in the nasal swabs and bronchioalveolar lavage fluid of pigs in T01 and T02 but not in the T03 and T04 groups. Similarly, lung lesions were observed in T01 and T02, but not in the T03 and T04 groups. No significant difference in terms of protection was observed between the T03 and T04 group. Collectively, our results demonstrate that the rPICV-H3 vectored vaccine elicited protective immunity against IAV-S challenge. This study shows that rPICV is a promising viral vector for the development of vaccines against IAV-S.

Value of IVIM in Differential Diagnoses between Benign and Malignant Solitary Lung Nodules and Masses: A Meta-analysis.

Purpose: This study aims to evaluate the accuracy of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in distinguishing malignant and benign solitary pulmonary nodules and masses. Methods: Studies investigating the diagnostic accuracy of IVIM-DWI in lung lesions published through December 2020 were searched. The standardized mean differences (SMDs) of the apparent diffusion coefficient (ADC), tissue diffusivity (D), pseudo-diffusivity (D*), and perfusion fraction (f) were calculated. The sensitivity, specificity, area under the curve (AUC), publication bias, and heterogeneity were then summarized, and the source of heterogeneity and the reliability of combined results were explored by meta-regression and sensitivity analysis. Results: A total of 16 studies including 714 malignant and 355 benign lesions were included. Significantly lower ADC, D, and f values were found in malignant pulmonary lesions compared to those in benign lesions. The D value showed the best diagnostic performance (sensitivity = 0.90, specificity = 0.71, AUC = 0.91), followed by ADC (sensitivity = 0.84, specificity = 0.75, AUC = 0.88), f (sensitivity = 0.70, specificity = 0.62, AUC = 0.71), and D * (sensitivity = 0.67, specificity = 0.61, AUC = 0.67). There was an inconspicuous publication bias in ADC, D, D* and f values, moderate heterogeneity in ADC, and high heterogeneity in D, D*, and f values. Subgroup analysis suggested that both ADC and D values had a significant higher sensitivity in "nodules or masses" than that in "nodules." Conclusions: The parameters derived from IVIM-DWI, especially the D value, could further improve the differential diagnosis between malignant and benign solitary pulmonary nodules and masses.Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/#myprospero, identifier: CRD42021226664.

Evaluating the Biological Role of Lassa Viral Z Protein-Mediated RIG-I Inhibition Using a Replication-Competent Trisegmented Pichinde Virus System in an Inducible RIG-IN Expression Cell Line.

Lassa virus (LASV) is a mammarenavirus that can cause lethal Lassa fever disease with no FDA-approved vaccine and limited treatment options. Fatal LASV infections are associated with innate immune suppression. We have previously shown that the small matrix Z protein of LASV, but not of a nonpathogenic arenavirus Pichinde virus (PICV), can inhibit the cellular RIG-I-like receptors (RLRs), but its biological significance has not been evaluated in an infectious virus due to the multiple essential functions of the Z protein required for the viral life cycle. In this study, we developed a stable HeLa cell line (HeLa-iRIGN) that could be rapidly and robustly induced by doxycycline (Dox) treatment to express RIG-I N-terminal effector, with concomitant production of type I interferons (IFN-Is). We also generated recombinant tri-segmented PICVs, rP18tri-LZ, and rP18tri-PZ, which encode LASV Z and PICV Z, respectively, as an extra mScarlet fusion protein that is nonessential for the viral life cycle. Upon infection, rP18tri-LZ consistently expressed viral genes at a higher level than rP18tri-PZ. rP18tri-LZ also showed a higher level of a viral infection than rP18tri-PZ did in HeLa-iRIGN cells, especially upon Dox induction. The heterologous Z gene did not alter viral growth in Vero and A549 cells by growth curve analysis, while LASV Z strongly increased and prolonged viral gene expression, especially in IFN-competent A549 cells. Our study provides important insights into the biological role of LASV Z-mediated RIG-I inhibition and implicates LASV Z as a potential virulence factor. IMPORTANCE Lassa virus (LASV) can cause lethal hemorrhagic fever disease in humans but other arenaviruses, such as Pichinde virus (PICV), do not cause obvious disease. We have previously shown that the Z protein of LASV but not of PICV can inhibit RIG-I, a cytosolic innate immune receptor. In this study, we developed a stable HeLa cell line that can be induced to express the RIG-I N-terminal effector domain, which allows for timely control of RIG-I activation. We also generated recombinant PICVs encoding LASV Z or PICV Z as an extra gene that is nonessential for the viral life cycle. Compared to PICV Z, LASV Z could increase viral gene expression and viral infection in an infectious arenavirus system, especially when RIG-I signaling is activated. Our study presented a convenient cell system to characterize RIG-I signaling and its antagonists and revealed LASV Z as a possible virulence factor and a potential antiviral target.