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Abstract Background Most Chinese blood centers have implemented mini pool (MP) HBV nucleic acid testing (NAT) together with HBsAg ELISA in routine blood donor screening for HBV infection since 2015, and a few centers upgraded MP to individual donation (ID) NAT screening recently, raising urgent need for cost-benefit analysis of different screening strategies. In an effort to prevent transfusion-transmitted infections (TTIs) for HBV, cost-benefit analyses of three different screening strategies: HBsAg alone, HBsAg plus MP NAT and HBsAg plus ID NAT were performed in blood donors from southern China where HBV infection was endemic. Methods MP-6 HBV NAT and ID NAT were adopted in parallel to screen blood donors for further comparative analysis. On the basis of screening data and the documented parameters, the number of window period (WP) infection, HBV acute infection, chronic hepatitis B infection (CHB) and occult hepatitis B infection (OBI) was evaluated, and the potential prevented HBV TTIs and benefits of these three strategies were predicted based on cost-benefit analysis by an estimation model. Results Of 132,323 donations, the yield rate for HBsAg-/DNA + screened by ID NAT (0.12%) was significantly higher than that by MP NAT (0.058%, P

Abstract Epstein-Barr virus (EBV) related post-transplant lymphoproliferative disorder (EBV-PTLD) is a life-threatening complication after hematopoietic stem cell transplantation (HSCT) or solid organ transplantation (SOT), for which no standard therapeutic means have been developed. Significant increase expression of natural killer group 2 member D ligands (NKG2DLs) was observed on B-lymphoblastoid cells of EBV-PTLD, indicating NKG2DLs as potential therapeutic targets for treatment of EBV-PTLD. In this study, the recombinant constructs of NKG2D CAR and IL-15/IL-15Rα-NKG2D CAR were generated with a retroviral vector and then transduced to human T cells to produce NKG2D CAR-T and IL-15/IL-15Rα-NKG2D CAR-T cells, respectively. B-lymphoblastoid cell lines (B-LCLs) and the xenografted mouse models were established to evaluate the efficacy of these CAR-T cells. IL-15/IL-15Rα-NKG2D CAR-T cells exhibited superior proliferation and antigen-specific cytotoxic effect compared to NKG2D CAR-T, as IL-15/IL-15Rα signaling promoted the expansion of less differentiated central memory T cells (TCM) and increased expression of CD107a and IFN-γ. Moreover, EBV DNA load was dramatically reduced, and 80% B-LCL cells were eliminated by IL-15/IL-15Rα-NKG2D CAR-T cells after co-culturing. In-vivo study confirmed that IL-15/IL-15Rα-NKG2D CAR-T cell therapy significantly enhanced antiviral efficacy in mice, as the serum load of EBV after IL-15/IL-15Rα-NKG2D CAR-T cell infusion was 1500 times lower than the untreated control (P

ABSTRACTTo successfully engineer large-sized tissues, establishing vascular structures is essential for providing oxygen, nutrients, growth factors and cells to prevent necrosis at the core of the tissue. The diameter scale of the biofabricated vasculatures should range from 100 to 1,000 µm to support the mm-size tissue while being controllably aligned and spaced within the diffusion limit of oxygen. In this review, insights regarding biofabrication considerations and techniques for engineered blood vessels will be presented. Initially, polymers of natural and synthetic origins can be selected, modified, and combined with each other to support maturation of vascular tissue while also being biocompatible. After they are shaped into scaffold structures by different fabrication techniques, surface properties such as physical topography, stiffness, and surface chemistry play a major role in the endothelialization process after transplantation. Furthermore, biological cues such as growth factors (GFs) and endothelial cells (ECs) can be incorporated into the fabricated structures. As variously reported, fabrication techniques, especially 3D printing by extrusion and 3D printing by photopolymerization, allow the construction of vessels at a high resolution with diameters in the desired range. Strategies to fabricate of stable tubular structures with defined channels will also be discussed. This paper provides an overview of the many advances in blood vessel engineering and combinations of different fabrication techniques up to the present time.

Objective To establish the indicator and fuzzy evaluation model for the procurement demonstration of key instruments and equipment, in order to provide a scientific and reliable method for the procurement demonstration of equipment in blood centers. Methods Through literature review and Delphi method, the procurement evaluation indexes of key instruments and equipment in blood centers were established. The weights of each index were calculated using analytic hierarchy process (AHP) by sending questionnaires to experts. According to the established indicator and fuzzy comprehensive evaluation method, a scoring model of procurement demonstration of key instruments and equipment was constructed. The blood screening total laboratory automation was analyzed and verified using the established demonstration model. Results A total of 4 first-level evaluation indicators and 16 second-level evaluation indicators were established. The weights of urgency, social benefit, economic benefit and technical condition were 0.496, 0.300, 0.051 and 0.153, respectively. For the blood screening assembly line system to be procured, the evaluation value was 0.629, and it passed the procurement demonstration. Conclusion The quantitative and scientific evaluation of the procurement evaluation can be carried out by establishing the evaluation index and fuzzy comprehensive evaluation method for the key instruments and equipment of blood centers.

Background: The prevalence of different types/subtypes varies across seasons and countries for seasonal influenza viruses, indicating underlying interactions between types/subtypes. The global interaction patterns and determinants for seasonal influenza types/subtypes need to be explored. Methods: Influenza epidemiological surveillance data, as well as multidimensional data that include population-related, environment-related, and virus-related factors from 55 countries worldwide were used to explore type/subtype interactions based on Spearman correlation coefficient. The machine learning method Extreme Gradient Boosting (XGBoost) and interpretable framework SHapley Additive exPlanation (SHAP) were utilized to quantify contributing factors and their effects on interactions among influenza types/subtypes. Additionally, causal relationships between types/subtypes were also explored based on Convergent Cross-mapping (CCM). Results: A consistent globally negative correlation exists between influenza A/H3N2 and A/H1N1. Meanwhile, interactions between influenza A (A/H3N2, A/H1N1) and B show significant differences across countries, primarily influenced by population-related factors. Influenza A has a stronger driving force than influenza B, and A/H3N2 has a stronger driving force than A/H1N1. Conclusion: The research elucidated the globally complex and heterogeneous interaction patterns among influenza type/subtypes, identifying key factors shaping their interactions. This sheds light on better seasonal influenza prediction and model construction, informing targeted prevention strategies and ultimately reducing the global burden of seasonal influenza.

Background: Nucleic acid testing (NAT) is widely used for screening blood donors for infectious diseases to enhance transfusion safety. Roche's advanced cobas® MPX assay detects human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) using the cobas® 6800/5800 Systems, based on real-time PCR technology, providing improved sensitivity. This study aims to evaluate the clinical sensitivity and specificity of the cobas® MPX assay and its effectiveness in identifying infected donors in HBV endemic areas, particularly those with occult HBV infection (OBI). Materials and methods: A total of 12,067 donor samples from the Dalian Blood Center (DLBC, northern China) were tested for HIV, HCV, and HBV using both the cobas® MPX assay on the cobas® 6800 system and the previous generation cobas® TaqScreen MPX test v2.0 on the cobas s 201 system as the reference method. Testing was conducted using individual-donation testing (IDT) and primary pool of six donations (PP6), following the manufacturer's instructions and the operational procedures of the instruments. Samples with inconsistent results underwent repeated confirmation tests. Results: Cobas® MPX demonstrated 100.00 % overall percent agreement (95 % CI, 99.22 %-100.00 %) for IDT and 99.89 % (95 % CI, 99.82 %-99.95 %) for PP6. Kappa coefficients were 1.0 for IDT and 0.76 for PP6. Cobas® MPX specificity was 100.00 % (95 % CI, 99.22 %-100.00 %) for IDT and 99.99 % (95 % CI, 99.94 %-100.00 %) for PP6. Sensitivity was 100.00 % (95 % CI, 2.50 %-100.00 %) for IDT and 86.67 % (95 % CI, 68.36 %-95.64 %) for PP6. A total of 12 HBV NAT-yield cases were detected by cobas® MPX. Conclusion: Cobas® MPX demonstrated outstanding sensitivity and specificity in screening HIV, HCV, and HBV in routine blood donations, particularly enhancing occult HBV detection in endemic regions.

Abstract Tissue engineering and regenerative medicine have made great progress in recent decades, as the fields of bioengineering, materials science, and stem cell biology have converged, allowing tissue engineers to replicate the structure and function of various levels of the vascular tree. Nonetheless, the lack of a fully functional vascular system to efficiently supply oxygen and nutrients has hindered the clinical application of bioengineered tissues for transplantation. To investigate vascular biology, drug transport, disease progression, and vascularization of engineered tissues for regenerative medicine, we have analyzed different approaches for designing microvascular networks to create models. This review discusses recent advances in the field of microvascular tissue engineering, explores potential future challenges, and offers methodological recommendations.

Objective To explore the the potential risks of antiretroviral therapy(ART) drugs on blood safety among blood donors in Shenzhen. Methods High pressure liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was used to measure ART drugs concentrations in the plasma of regular blood donors (negative control group, n=86) and anti-HIV positive individuals (experimental group, n=98, detected from approximately 440 000 blood donors during 2019—2023). The baseline plasma concentrations of ART drugs in the negative control group were clarified, and the impact of ART drugs on blood safety was analyzed. Results The baseline concentrations of ART drugs were not detected in 86 samples of negative control group. Four positive ART drugs samples were detected in 1∶2 pooled plasma samples of 98 anti-HIV positive blood donors plasma in the resolution test. The ART positive rate of anti-HIV positive donors was 4.08%, with tenofovir, lamivudine and efavirenz detected in three blood donors and lamivudine, lopinavir, ritonavir and zidovudine detected in one blood donor. Conclusion ART drugs were found among anti-HIV positive blood donors in Shenzhen. Additional research is needed to investigate the motivation of these specific donors, so as to ascertain the groups most susceptible to potential risks, and guarantee blood safety.

Objective To investigate asymptomatic infection of hepatitis B virus(HBV) among hepatitis B vaccinated donors in Shenzhen, and analyze its serological and molecular characteristics. Methods The HBsAg ELISA positive blood samples of blood donors born after 1992 were collected. HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc were further detected by Roche electrochemiluminescence immunoassay (ECL). BCP/PC and S regions were amplified by Nested-PCRs, HBV DNA quantification were adopted by qPCR simultaneously, and the sequences were also analyzed. Results A total of 46 632 blood samples of donors(31 612 males and 15 020 females) from December 2020 to January 2022 collected, and 99 samples with HBsAg ELISA positive were screened out. After tested by ECL, Nested-PCRs, and real-time fluorescence PCR, 61 were confirmed HBsAg positive, with the positive rate at 0.13% (61/46 632), including 49 males (0.16%, 49/31 612) and 12 females (0.08%, 12/15 020). The HBsAg positive rate of males was higher than that of females (P

Objective To analyze the results of different methods for reactive samples screened by the enzyme linked immunosorbent assay (ELISA) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in blood donors. Methods From March to April 2020, a total of 8 632 blood samples in Shenzhen were screened for SARS-CoV-2 total antibodies (TAb, including IgG, IgM, IgA) in plasma using ELISA(PC group), the antibody reactivity samples and their follow up plasma samples (FC group), and samples of disease control group(DC group) from January to April 2020 were detected using the following methods: 1) ELISA method for detecting IgG, IgM, and (or without detection) TAb; 2) pseudovirus neutralizing antibody test(pVNT); 3) western blot (WB) of SARS-CoV-2 antibody. The negative control group(NC group) from February to April 2020 performed ELISA and WB testing. Results Among the 34 total antibody positive samples, 2 were positive for pVNT test, and the total antibody, IgG and WB in the initial screening and tracking testing were positive. Thereafter, it was determined to be confirmed positive. The other 2 cases were positive for pVNT test, while the samples with positive WB results were in the follow-up stage. The TAb, IgG, and pVNT results did not conform to the dynamic evolution of antibodies, and cannot be determined as confirmed positive. Conclusion The infection status of antibody reactivity samples screened by SARS-CoV-2 ELISA can be judged by the logic of pVNT, WB and the dynamic change of antibody.

Objective To establish a magnetic bead enrichment strategy for the detection of human immunodeficiency virus deoxyribonucleic acid (HIV DNA) in peripheral blood, and to verify the improvement of the sensitivity of this method for the detection of HIV DNA in HIV infected patients after early antiretrovital treatment (ART). Methods Peripheral whole blood was collected at 4 timepoints in one ART HIV window period (WP) patient. Peripheral blood mononuclear cells (PBMCs) were isolated on a Ficoll gradient. CD4+ T lymphocytes were enriched from total PBMCs by negative sorting. HIV DNA concentration in magnetic beads enriched group and whole blood group was detected by HIV DNA detection kit. Results CD4+ T cells were isolated by magnetic beads and identified by FCM for purity at (96.4 ± 2.6)%. The viability was (95.9 ± 2.9)%, as demonstrated by trypan blue staining. The person on continued ART treatment in this study had significantly greater reduction in HIV viral load and undetectable HIV plasma RNA at follow up timepoint 4. No HIV DNA was detected in the whole blood group at all 4 timepoints. The quantitative results of HIV DNA in the CD4+ T lymphocyte group of the magnetic bead enrichment group were 73.4, 429.3, 137.1, 449.9 copies/106 CD4+ T cell′s respectively. Conclusion The magnetic bead enrichment method can be more sensitive in detecting the limit low copy HIV DNA in blood samples, and provide early confirmatory data for HIV WP infection and breakthrough infection after ART treatment.

Objective To analyze the SARS-CoV-2 detection results among blood donors in different periods of COVID-19 pandemic control in Shenzhen and assess the antibody levels and infection status of blood donors in different periods, so as to provide reference for subsequent blood testing strategies. Methods A total of 4 768 plasma samples of blood donors were subjected to pooled testing by nucleic acid testing(NAT) with 8 samples per pool. Additionally, these samples were subjected to a 1000-fold dilution, and the detection of SARS-CoV-2 total antibody was performed by enzyme-linked immunosorbent assay (ELISA). The 4 768 plasma samples were collected from blood donors at different time points in Shenzhen, with inquiries made to determine whether donors during the COVID-19 pandemic were in the convalescence. The antibody positive rates in blood screening samples during different periods of the pandemic and samples from individuals in the convalescence of COVID-19 infection were analyzed. Furthermore, the antibody levels were examined for differences based on gender, age, and blood type. Results All 4 768 plasma samples from blood donors were negative by NAT, while 2 342 samples were detected positive by the SARS-CoV-2 total antibody detection, with a positive rate of 49.1%. These samples from four periods (September 30 to October 3, 2022; November 3 to 6, 2022; December 27 to 31, 2022; January 6 to 18, 2023) were subjected to a 1 000-fold dilution for COVID-19 antibody detection, and the positive rates were 21.3%, 15.8%, 65.9%, and 93.9%, respectively. Conclusion The prevalence of COVID-19 antibodies among blood donors in Shenzhen during different periods of the pandemic varied significantly. There was no difference in antibody prevalence among different genders and blood types, while younger individuals exhibited a higher prevalence of antibodies. The risk of COVID-19 transmission through blood transfusion was found to be extremely low.

Yearly epidemics of seasonal influenza cause an enormous disease burden around the globe. An understanding of the rules behind the immune response with repeated vaccination still presents a significant challenge, which would be helpful for optimizing the vaccination strategy. In this study, 34 healthy volunteers with 16 vaccinated were recruited, and the dynamics of the BCR repertoire for consecutive vaccinations in two seasons were tracked. In terms of diversity, length, network, V and J gene segments usage, somatic hypermutation (SHM) rate and isotype, it was found that the overall changes were stronger in the acute phase of the first vaccination than the second vaccination. However, the V gene segments of IGHV4-39, IGHV3-9, IGHV3-7 and IGHV1-69 were amplified in the acute phase of the first vaccination, with IGHV3-7 dominant. On the other hand, for the second vaccination, the changes were dominated by IGHV1-69, with potential for coding broad neutralizing antibody. Additional analysis indicates that the application of V gene segment for IGHV3-7 in the acute phase of the first vaccination was due to the elevated usage of isotypes IgM and IgG3. While for IGHV1-69 in the second vaccination, it was contributed by isotypes IgG1 and IgG2. Finally, 41 public BCR clusters were identified in the vaccine group, with both IGHV3-7 and IGHV1-69 were involved and representative complementarity determining region 3 (CDR3) motifs were characterized. This study provides insights into the immune response dynamics following repeated influenza vaccination in humans and can inform universal vaccine design and vaccine strategies in the future.

3D printing as a powerful technology enables the fabrication of organ structures with a programmed geometry, but it is usually difficult to produce large-size tissues due to the limited working space of the 3D printer and the instability of bath or ink materials during long printing sessions. Moreover, most printing only allows preparation with a single ink, while a real organ generally consists of multiple materials. Inspired by the 3D puzzle toy, we developed a “building block-based printing” strategy, through which the preparation of 3D tissues can be realized by assembling 3D-printed “small and simple” bio-blocks into “large and complex” bioproducts. The structures that are difficult to print by conventional 3D printing such as a picture puzzle consisting of different materials and colors, a collagen “soccer” with a hollow yet closed structure, and even a full-size human heart model are successfully prepared. The 3D puzzle-inspired preparation strategy also allows for a reasonable combination of various cells in a specified order, facilitating investigation into the interaction between different kinds of cells. This strategy opens an alternative path for preparing organ structures with multiple materials, large size and complex geometry for tissue engineering applications.

The blood-brain barrier (BBB) is a type of capillary network characterized by a highly selective barrier, which restricts the transport of substances between the blood and nervous system. Numerous in vitro models of the BBB have been developed for drug testing, but a BBB model with controllable capillary structures remains a major challenge. In this study, we report for the first time a unique method of controlling the blood capillary networks and characteristic holes formation in a BBB model by varying the elastic modulus of a three-dimensional scaffold. The characteristic hole structures are formed by the migration of endothelial cells from the model surface to the interior, which have functions of connecting the model interior to the external environment. The hole depth increased, as the elastic modulus of the fibrin gel scaffold increased, and the internal capillary network length increased with decreasing elastic modulus. Besides, internal astrocytes and pericytes were also found to be important for inducing hole formation from the model surface. Furthermore, RNA sequencing indicated up-regulated genes related to matrix metalloproteinases and angiogenesis, suggesting a relationship between enzymatic degradation of the scaffolds and hole formation. The findings of this study introduce a new method of fabricating complex BBB models for drug assessment.

Objective To analyze the cost-effectiveness of ELISA grey area strategy through establishing the health economics model. Methods The serological grey area strategy evaluation model was composed of screening strategy subdecision tree, pathogen infection subdecision tree and pathogen detection subdecision tree. The key parameters in the model were obtained from literatures and research data. The cost-effectiveness of setting ELISA grey area strategy was compared by software, and multifactor sensitivity analysis was conducted. Results After setting the ELISA grey area, extra samples(5.86 cases/100 000) with serological false negativity could be detected, including HBV samples at 4.93/100 000, HCV samples at 0.27/100 000, HIV samples at 0/100 000, syphilis samples at 0.66/100 000. To yield an additional seropositive sample out of every 100 000 blood donors, blood center will afford extra 1 million yuan about. Conclusion Through this study, a cost-effectiveness evaluation model of serological detection strategy was established. Although the ELISA grey area setting can yield a small number of seropositive samples, the cost is much higher than the current affordability.

Objective To investigate the prognosis of blood donors with occult hepatitis B virus infection (OBI) by long-term follow-up and repeated testing of HBsAg and HBV DNA. Methods From January 1, 2010 to December 31, 2020, voluntary blood donors were screened by both serological and viral nucleic acid(NAT) testing, then samples were further confirmed as HBV DNA positive by manual nested-PCR amplification.A total of 306 cases were detected as HBsAg negative /HBV DNA positive, then followed-up for a long time and re-examined of HBsAg and HBV DNA to confirm whether they had infected with OBI.The prognosis of patients with OBI who experienced long-term immunization was determined by repeated testing. Results A total of 306 HBsAg negative/ HBV DNA positive blood donors had been followed up, and 40(13.07%, 40/306) were recalled frequently for re-examination.Among them, 90%(36/40), 57.5%(23/40), 40% (16/40)were anti-HBc + , anti-HBs + and anti-HBe + , respectively, and 50%(20/40), 40%(16/40), 7.5%(3/40) and 2.5% (1/40)were anti-HBs+ / anti-HBc + , anti-HBc + / anti-HBs -, anti-HBc -/ anti-HBs + and anti-HBc -/ anti-HBs -, respectively.Those 40 blood donors were followed-up for 1-13 times, with the duration of 8-108 months (0.6~9 years).1 donor (2.5%) was followed-up less than 1 year, 11 (27.5%)>1 year and ≤3 years, 23 (57.5%) 23(57.5%)>3 years and ≤5 years, and 5 (12.5%) for more than 5 years.After long-term following up and repeated testing, 50%(20/40)of OBI blood donors turned negative for HBV DNA (HBsAg negative / HBV DNA negative), 42.5% (17/40)were confirmed as OBI infection (HBsAg negative / HBV DNA positive), and 7.5%(3/40) were hard to determine (after repeated testing, the results were either positive or negative). Conclusion After long-term following up and repeated screening, we found that none of the OBI patients turned into acute or chronic HBV infection, and most of them maintained OBI.However, OBI blood donors carry very low load of HBV DNA for a long time, which could lead to false negative results of NAT and bring a great challenge to the safety of blood transfusion.

Abstract Background A range of strict nonpharmaceutical interventions (NPIs) were implemented in many countries to combat the coronavirus 2019 (COVID-19) pandemic. These NPIs may also be effective at controlling seasonal influenza virus infections, as influenza viruses have the same transmission path as severe acute respiratory syndrome coronavirus 2. The aim of this study was to evaluate the effects of different NPIs on the control of seasonal influenza. Methods Data for 14 NPIs implemented in 33 countries and the corresponding influenza virological surveillance data were collected. The influenza suppression index was calculated as the difference between the influenza positivity rate during its period of decline from 2019 to 2020 and during the influenza epidemic seasons in the previous 9 years. A machine learning model was developed using an extreme gradient boosting tree regressor to fit the NPI and influenza suppression index data. The SHapley Additive exPlanations tool was used to characterize the NPIs that suppressed the transmission of influenza. Results Of all NPIs tested, gathering limitations had the greatest contribution (37.60%) to suppressing influenza transmission during the 2019–2020 influenza season. The three most effective NPIs were gathering limitations, international travel restrictions, and school closures. For these three NPIs, their intensity threshold required to generate an effect were restrictions on the size of gatherings less than 1000 people, ban of travel to all regions or total border closures, and closing only some categories of schools, respectively. There was a strong positive interaction effect between mask-wearing requirements and gathering limitations, whereas merely implementing a mask-wearing requirement, and not other NPIs, diluted the effectiveness of mask-wearing requirements at suppressing influenza transmission. Conclusions Gathering limitations, ban of travel to all regions or total border closures, and closing some levels of schools were found to be the most effective NPIs at suppressing influenza transmission. It is recommended that the mask-wearing requirement be combined with gathering limitations and other NPIs. Our findings could facilitate the precise control of future influenza epidemics and other potential pandemics.

Objective To establish a routine screening method for unexpected antibodies of blood donors, analyze the results of centralized screening for unexpected antibody of blood donors in the blood center, and compare the cost of centralized and decentralized screening modes. Methods A total of 35 591 blood donors were screened for unexpected antibodies from March 31, 2021 to July 31, 2021, using microcolumn gel method. Unexpected antibody screening reactive samples were further confirmed by the Transfusion Research Institute of Shenzhen Blood Center, and the demographic characteristics were further determined through the analysis of unexpected antibody positive population. The direct cost and indirect cost of centralized and decentralized unexpected antibody screening mode were compared. Results Forty unexpected antibody positive samples were confirmed in Shenzhen, with the positive rate at 0.11%(40/35 591), among which MNS, Rh and Lewis system accounted for 35% (14/40), 32.5% (13/40) and 17.5% (7/40), respectively. Males and females accounted for 45% (18/40) and 55% (22/40), respectively (P0.05). Unexpected antibody screening in a centralized way saved about 1.16 million yuan per year. Conclusion It is necessary to carry out unexpected antibody screening for all blood donors, and centralized screening is more economical than decentralized screening.

Objective To establish scrap indicators for key equipment in blood screening laboratory of blood centers and quantitatively assess the running status of key equipment, so as to provide a scientific method for equipment scrap. Methods Through the literature review and Delphi method, the scrap indicators of key equipment in blood screening laboratories were established in terms of applicability, economy and advancement of the equipment. The weights of relevant indicators were calculated by analysis hierarchy process (AHP), and the quantitative assessment model of equipment scrap priority was established according to the indicators and its weight. The equipment running data from January 2020 to December 2020 of Laboratory Department were collected and analyzed using the model, and its accuracy was verified based on experience. Results Thirteen second-level scrap indicators were established, and the weights of the three first-level indexes of applicability, economy and advancement were 0.582, 0.114 and 0.306, respectively. Among the total 30 key equipment, the model score of 4 equipment was less than 0.5, and the running status after manually checking met the scrap standard. Conclusion The model can accurately assess the scrap priority of key equipment and facilitate the procurement budget and scrapping identification in advance, which can avoid the waste of resources and ensure safe, efficient and orderly laboratory work.

Objective To assess three severe acute respiratorysyndrome coronavirus 2 (SARS-CoV-2) enzyme linked immunosorbent assays (ELISA) and one pseudotype lentivirus-based neutralization test (ppNAT) in detecting the convalescent plasma antibody levles from COVID-19. Methods 30 COVID-19 convalescent plasma samples were screened for antibodies against SARS-CoV-2 using three kinds of SARS-CoV-2 ELISA reagents and one ppNAT test in Shenzhen. The controls consisted of plasma samples from 32 healthy blood donors in February 2019. The diagnostic efficacy analysis of various SARS-CoV-2 ELISA reagents was performed using real-time fluorescent Polymerase Chain Reaction (RT-PCR). We also analyzed correlation between different immunological reagents and the age, gender, hospitalization, and severity of illness. Results The positive yielding rate of ppNAT and three kinds of IgG ELISA was higher than that of IgM ELISA. The positive yielding rates of three kinds of IgG ELISA were 100%(30/30), 93.33%(28/30), and 96.67%(29/30) respectively, while the yielding rates in control group were all 0. The positive yielding rate of three IgM ELISAs were 93.33%(28/30), 70%(21/30)and 46.67% (14/30). All the cases from negative control group were negative for IgG and IgM. Pearson correlation coefficient was calculated; there was a strong correlation between ELISA reagent 2 IgG and ELISA reagent 3 IgG (r=0.765, P0.05). Conclusion In the convalescent plasma with nucleic acid confirmed covid-19, the yielding rates of different IgM antibodies varied greatly. Antibody levels were influenced by age to some extent.

Objective To evaluate the performance and clinical application of a high-throughput nucleic acid blood screening detection system for SARS-CoV-2, so as to provide basis and technical means for its application in detection of plasma from recovered COVID-19 patients. Methods The SARS-CoV-2 nucleic acid was detected by real-time fluorescence quantitative PCR, and the sensitivity, precision, anti-interference and other parameters were evaluated. Blood donor samples collected during COVID-19 epidemic period were screened using the detection system to evaluate its applicability. Results The detection limits of gene N and ORF 1ab were 3.98 copies/mL and 9.38 copies/mL, respectively. The CV of high and low concentration samples were both less than 5%. Hemoglobin at 500 mg/dL and triglyceride at 3g/dL had little effect on the results. The detection system can effectively prevent carryover, thus avoiding false positive results. The SARS-CoV-2 nucleic acid blood screening was carried out in a total of 39 306 blood samples, and all samples were negative. Conclusion The established method can meet the needs of SARS-CoV-2 nucleic acid screening therefore ensure the safe application of plasma from recovered COVID-19 patients.

IntroductionCoronavirus disease 2019 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Influential variants and mutants of this virus continue to emerge, and more effective virus-related information is urgently required for identifying and predicting new mutants. According to earlier reports, synonymous substitutions were considered phenotypically silent; thus, such mutations were frequently ignored in studies of viral mutations because they did not directly cause amino acid changes. However, recent studies have shown that synonymous substitutions are not completely silent, and their patterns and potential functional correlations should thus be delineated for better control of the pandemic.MethodsIn this study, we estimated the synonymous evolutionary rate (SER) across the SARS-CoV-2 genome and used it to infer the relationship between the viral RNA and host protein. We also assessed the patterns of characteristic mutations found in different viral lineages.ResultsWe found that the SER varies across the genome and that the variation is primarily influenced by codon-related factors. Moreover, the conserved motifs identified based on the SER were found to be related to host RNA transport and regulation. Importantly, the majority of the existing fixed-characteristic mutations for five important virus lineages (Alpha, Beta, Gamma, Delta, and Omicron) were significantly enriched in partially constrained regions.DiscussionTaken together, our results provide unique information on the evolutionary and functional dynamics of SARS-CoV-2 based on synonymous mutations and offer potentially useful information for better control of the SARS-CoV-2 pandemic.

IntroductionInfluenza susceptibility difference is a widely existing trait that has great practical significance for the accurate prevention and control of influenza.MethodsHere, we focused on the human susceptibility to the seasonal influenza A/H3N2 of healthy adults at baseline level. Whole blood expression data for influenza A/H3N2 susceptibility from GEO were collected firstly (30 symptomatic and 19 asymptomatic). Then to explore the differences at baseline, a suite of systems biology approaches - the differential expression analysis, co-expression network analysis, and immune cell frequencies analysis were utilized.ResultsWe found the baseline condition, especially immune condition between symptomatic and asymptomatic, was different. Co-expression module that is positively related to asymptomatic is also related to immune cell type of naïve B cell. Function enrichment analysis showed significantly correlation with “B cell receptor signaling pathway”, “immune response−activating cell surface receptor signaling pathway” and so on. Also, modules that are positively related to symptomatic are also correlated to immune cell type of neutrophils, with function enrichment analysis showing significantly correlations with “response to bacterium”, “inflammatory response”, “cAMP−dependent protein kinase complex” and so on. Responses of symptomatic and asymptomatic hosts after virus exposure show differences on resisting the virus, with more effective frontline defense for asymptomatic hosts. A prediction model was also built based on only baseline transcription information to differentiate symptomatic and asymptomatic population with accuracy of 0.79.DiscussionThe results not only improve our understanding of the immune system and influenza susceptibility, but also provide a new direction for precise and targeted prevention and therapy of influenza.

Circulation of seasonal influenza is the product of complex interplay among multiple drivers, yet characterizing the underlying mechanism remains challenging. Leveraging the diverse seasonality of A(H3N2) virus and abundant climatic space across regions in China, we quantitatively investigated the relative importance of population susceptibility, climatic factors, and antigenic change on the dynamics of influenza A(H3N2) through an integrative modelling framework. Specifically, an absolute humidity driven multiscale transmission model was constructed for the 2013/2014, 2014/2015 and 2016/2017 influenza seasons that were dominated by influenza A(H3N2). We revealed the variable impact of absolute humidity on influenza transmission and differences in the occurring timing and magnitude of antigenic change for those three seasons. Overall, the initial population susceptibility, climatic factors, and antigenic change explained nearly 55% of variations in the dynamics of influenza A(H3N2). Specifically, the additional variation explained by the initial population susceptibility, climatic factors, and antigenic change were at 33%, 26%, and 48%, respectively. The vaccination program alone failed to fully eliminate the summer epidemics of influenza A(H3N2) and non-pharmacological interventions were needed to suppress the summer circulation. The quantitative understanding of the interplay among driving factors on the circulation of influenza A(H3N2) highlights the importance of simultaneous monitoring of fluctuations for related factors, which is crucial for precise and targeted prevention and control of seasonal influenza.

The immune system is highly networked and complex, which is continuously changing as encountering old and new pathogens. However, reductionism-based researches do not give a systematic understanding of the molecular mechanism of the immune response and viral pathogenesis. Here, we present HUMPPI-2022, a high-quality human protein-protein interaction (PPI) network, containing > 11,000 protein-coding genes with > 78,000 interactions. The network topology and functional characteristics analyses of the immune-related genes (IRGs) reveal that IRGs are mostly located in the center of the network and link genes of diverse biological processes, which may reflect the gene pleiotropy phenomenon. Moreover, the virus-human interactions reveal that pan-viral targets are mostly hubs, located in the center of the network and enriched in fundamental biological processes, but not for coronavirus. Finally, gene age effect was analyzed from the view of the host network for IRGs and virally-targeted genes (VTGs) during evolution, with IRGs gradually became hubs and integrated into host network through bridging functionally differentiated modules. Briefly, HUMPPI-2022 serves as a valuable resource for gaining a better understanding of the composition and evolution of human immune system, as well as the pathogenesis of viruses.

Here, the authors determine seroprevalence of antibodies to SARS-CoV-2 in healthy blood donors in the cities of Wuhan, Shenzhen, and Shijiazhuang in China between January and April 2020. The age- and sex-standardized SARS-CoV-2 seroprevalence among 18–60 year-old adults is, with 2.66%, the highest in Wuhan.

Abstract Background Hepatitis B virus (HBV) infection is a major concern for blood safety in high-prevalence HBV countries such as China. In Shenzhen, dual hepatitis B surface antigen (HBsAg) enzyme-linked immunosorbent assays (ELISAs) have been adopted in parallel with nucleic acid testing (NAT) for donors for over a decade. A small proportion of blood donors test reactive (R) for HBsAg but negative through routine NAT, which can lead to HBV infection with an extremely low viral load. Objectives We aimed to investigate and analyze the molecular characteristics of HBV among blood donors that tested HBsAg R in a single ELISA test. Methods Blood donations were evaluated in this study if confirmed HBsAg R through one of two ELISA kits. Samples with non-reactive (NR) results by NAT were collected and tested for HBsAg by chemiluminescent microparticle immunoassay (CLIA) with a neutralization test. The level of HBsAg was further assessed by electrochemiluminescence immunoassay (ECLIA). The viral basic core promoter (BCP) and pre-core (PC) and S regions were amplified by nested PCR. Quantitative real-time PCR (qPCR) for viral load determination and individual donation (ID)-NAT were adopted simultaneously. HBsAg was confirmed with CLIA, ECLIA, nested PCR, qPCR, and ID-NAT. Results Of the 100,252 donations, 38 and 41 were identified as HBsAg R with Wantai and DiaSorin ELISA kits, respectively. Seventy-nine (0.077%, 79/100,252) blood samples with ELISA R-NR and NAT NR results were enrolled in the study. Of these, 17 (21.5%,17/79) were confirmed as HBsAg-positive. Of the 14 genotyped cases, 78.6% (11/14) were genotype B, and C and D were observed in two and one sample, respectively. Mutations were found in the S gene, including Y100C, Y103I, G145R, and L175S, which can affect the detection of HBsAg. A high-frequency mutation, T1719G (93.3%), was detected in the BCP/PC region, which reduced the viral replication. Conclusion A small number of blood samples with HBsAg ELISA R-NR and NAT NR results were confirmed as HBV infection, viral nucleic acids were found in most of the samples through routine NAT methods. It is necessary to employ more sensitive and specific assays for the detection of HBV infection among blood donors.

COVID-19 vaccines are being developed urgently worldwide. Here, we constructed two adenovirus vectored COVID-19 vaccine candidates of Sad23L-nCoV-S and Ad49L-nCoV-S carrying the full-length gene of SARS-CoV-2 spike protein. The immunogenicity of two vaccines was individually evaluated in mice. Specific immune responses were observed by priming in a dose-dependent manner, and stronger responses were obtained by boosting. Furthermore, five rhesus macaques were primed with 5 × 109 PFU Sad23L-nCoV-S, followed by boosting with 5 × 109 PFU Ad49L-nCoV-S at 4-week interval. Both mice and macaques well tolerated the vaccine inoculations without detectable clinical or pathologic changes. In macaques, prime-boost regimen induced high titers of 103.16 anti-S, 102.75 anti-RBD binding antibody and 102.38 pseudovirus neutralizing antibody (pNAb) at 2 months, while pNAb decreased gradually to 101.45 at 7 months post-priming. Robust T-cell response of IFN-γ (712.6 SFCs/106 cells), IL-2 (334 SFCs/106 cells) and intracellular IFN-γ in CD4+/CD8+ T cell (0.39%/0.55%) to S peptides were detected in vaccinated macaques. It was concluded that prime-boost immunization with Sad23L-nCoV-S and Ad49L-nCoV-S can safely elicit strong immunity in animals in preparation of clinical phase 1/2 trials.

BackgroundAll Chinese blood centers have implemented mini pool (MP) HBV nucleic acid testing (NAT) together with HBsAg ELISA in routine donor screening since 2015. The prevalence of occult hepatitis B virus infection (OBI) in donors from different regions varies, and the molecular characterization of the HBV DNA and clinical outcomes of these OBIs remain largely unexplored.MethodsBlood donations from Heyuan city in Southern China were screened by HBsAg ELISA and HBV MP8 NAT. Donations with HBsAg-/HBV DNA+ were collected for this study. Molecular characterizations of HBV DNAs were further analyzed by various DNA amplification assays including quantitative PCR (qPCR) and nested PCR, amplifying the basic core and pre-core promoter regions (BCP/PC). The HBsAg (S) region from HBV DNA was isolated by high-volume nucleic acid extraction. Notable mutations were identified by comparison to the HBV reference sequences. The clinical outcomes of the donors with OBIs were further followed for nearly 3 years.ResultsSeventy OBIs from 44,592 donations (0.15%) that we identified and reported previously were enrolled for this current study. HBV sequences were obtained from 44/70 OBIs, and genotyping analysis showed that 42/44 (95.2%) OBIs were genotype B, and 2/44 (4.8%) were genotype C. Interestingly, mutation analysis revealed that various mutations including M133L/T, F134L, P142L, V168A, R169H, S174N, L175S, and V177A of HBV DNA affecting HBsAg detection were observed in genotype B OBIs. Two notable mutations, T47K and L53S, were identified in genotype C OBIs. Follow-up studies showed that 3/31 (9.7%) OBIs converted to HBsAg+ as chronic infections while 1/31 (3.2%) HBV DNA was undetectable (classified as recovery) and 27/31 (87.1%) remained as OBIs.ConclusionVarious notable mutations affecting HBsAg detection were observed in blood donors with OBIs in Heyuan city of Southern China. Follow-up studies showed that most OBIs remained as OBIs with fluctuating or low viral loads. Higher sensitive HBV ID NAT is recommended for donor screening to further reduce the transmission risk of OBIs.

Abstract Background Human T-cell lymphotropic virus (HTLV) remains a major safety concern for blood supplies. Despite many HTLV positive cases being reported in southeastern China, the detection of HTLV has not been prioritized in routine blood screening. Additionally, data on the prevalence of HTLV infection among blood donors is also limited. The objective of this study was to investigate the prevalence of HTLV among blood donors in three Chinese provinces through their representative blood centers, to evaluate the feasibility of chemiluminescence immunoassay (CLIA) for blood screening. Methods From November 2018 to March 2019, blood plasma samples were collected from Hebei, Changsha, and Shenzhen blood centers and were screened for the HTLV-1/2 antibody using a CLIA and enzyme-linked immunosorbent assay (ELISA). This was followed by confirmatory tests using INNO-LIA HTLV I/II. Results A total of 59,929 blood donations were collected and screened for HTLV-1/2. The reactive rate of CLIA and ELISA among donations in the Shenzhen blood center (0.0943%, 27/28,621) was higher than Hebei (0.0248%, 4/16,144), and Changsha (0.0198%, 3/15,164) (p

BackgroundMost Chinese Blood Centers adopted mini pool (MP) nucleic acid testing (NAT) for HBV screening due to high cost of Individual donation (ID) NAT, and different proportions of MP-reactive but ID-non-reactive donations (MP+/ID−, defined as non-resolved donations) have been observed during daily donor screening process. Some of these non-resolved donations are occult HBV infections (OBIs), which pose potential risk of HBV transmission if they are not deferred. This study is aimed to further analyze these non-resolved donations.MethodsThe non-resolved plasma samples were further analyzed by serological tests and various HBV DNA amplification assays including quantitative PCR (qPCR) and nested PCR amplifying the basic core and pre-core promoter regions (BCP/PC; 295 base pairs) and HBsAg (S) region (496 base pairs). Molecular characterizations of HBV DNA+ non-resolved samples were determined by sequencing analysis.ResultsOf 17,226 MPs from 103,356 seronegative blood donations, 98 MPs were detected reactive for HBV. Fifty-six out of these 98 (57.1%) reactive MPs were resolved as HBV DNA+, but the remaining 42 pools (42.9%, 252 donations) were left non-resolved with a high rate (53.2%) of anti-HBc+. Surprisingly, among 42 non-resolved MPs, 17 contained one donation identified as OBIs by alternative NAT assays. Sequence analysis on HBV DNAs extracted from these OBI donations showed some key mutations in the S region that may lead to failure in HBsAg detection and vaccine escape.ConclusionA total of 53.2% of the non-resolved donations were anti-HBc+, and OBIs were identified in 40.5% of these non-resolved pools. Therefore, non-resolved donations with anti-HBc+ might pose potential risk for HBV transmission. Our present analysis indicates that anti-HBc testing in non-resolved donations should be used to identify OBIs in order to further increase blood safety in China.

Abstract Background Blood donor plasma samples were detected by the Ultrio Plus NAT system for HBV, HCV and HIV-1 in Shenzhen blood center, China. Reactive samples underwent further discriminatory testing of a single virus by the same methodology. A large number of cases of non-discriminated reactive (NDR) donors were found, leaving potential risk of transmitting HBV if not deferrals. This study identified those non-discriminated samples. Methods The NDR plasma samples from blood donation screening were detected and classified by additional molecular and serological tests. Molecular characterizations of DNA+ NDR were determined by sequencing analysis. Results A number of 259 (0.21%) NDR plasma samples from screening of 123,280 eligible blood donors were detected, which presented a higher rate (91.1%) of anti-HBc reactivity and nearly half (46.7%) of HBV DNA+ that classified as occult HBV infection (OBI). Most OBI strains were wild-type HBV, but some substitutions V168A, S174 N, V177A, Q129R/L/H, G145A/R in S region of genotype B (OBIB) and T47K/V/A, P49H/L, Q101R/H/K, S174 N, L175S, V177A, T118 M/R/K, G145R/A/K/E, R160K/N in S region of genotype C (OBIC) strains were identified in high frequency. Conclusion Nearly half of NDR blood samples were identified as OBI, in which a number of important mutations were detected. NDR donation might have potential risk for HBV transmission, but need to be further investigated.

Owning to the extreme difficulty in identifying the primary generation (G0), the common ancestor of various twin-tail goldfish strains remains unclear. However, several authors have hypothesized that this ancestor may have been the crucian carp (Carassius auratus). Previously, we generated an experimental hybrid goldfish (EG) from the interspecific hybridization of red crucian carp (Carassius auratus ♀, RCC) × common carp (Cyprinus carpio ♂, CC). Unlike either parent, EG possessed twin caudal fins similar to those of natural goldfish (Carassius auratus, NG). The genetic characteristics of EG, as well as the mechanisms underlying its formation, are largely unknown. Here, we identified the genetic variation in the chordin gene that was associated with the formation of the twin-tail phenotype in EG: a stop codon mutation at the 127th amino acid. Furthermore, simple sequence repeat (SSR) genotyping indicated that, among the six alleles, all of the EG alleles were also present in female parent (RCC), but alleles specific to the male parent (CC) were completely lost. At some loci, EG and NG alleles differed, showing that these morphologically similar goldfish were genetically dissimilar. Collectively, our results demonstrated that genetic variations and differentiation contributed to the changes of morphological characteristics in hybrid offspring. This analysis of genetic variation in EG sheds new light on the common ancestor of NG, as well as on the role of hybridization and artificial breeding in NG speciation.

Solvothermal method is a very common synthetic method in the preparation of catalysts for the hydrogen evolution reaction (HER) of H2O decomposition. Since a certain surfactant can be added to the solvothermal solvent, the crystal particle growth process can be changed to obtain catalysts with different morphologies. We synthesized a series of nickel-manganese oxides (NiMnO) by adding different amounts of Polyethylene glycol (PEG) using the solvothermal method. Structure characterizations exhibit that NiMnO catalyst prepared with different PEG additions have different morphologies. The NiMnO catalyst prepared by adding 3 g of PEG possesses abundant petal-like scales, it brings a large specific surface area, high reaction efficiency, and has the best electrocatalytic activity in alkaline media.

With the rapid global spread of the Coronavirus Disease 2019 (COVID-19) pandemic, a safe and effective vaccine against human coronaviruses (HCoVs) is believed to be a top priority in the field of public health. Due to the frequent outbreaks of different HCoVs, the development of a pan-HCoVs vaccine is of great value to biomedical science. The antigen design is a key prerequisite for vaccine efficacy, and we therefore developed a novel antigen with broad coverage based on the genetic algorithm of mosaic strategy. The designed antigen has a potentially broad coverage of conserved cytotoxic T lymphocyte (CTL) epitopes to the greatest extent, including the existing epitopes from all reported HCoV sequences (HCoV-NL63, HCoV-229E, HCoV-OC43, HCoV-HKU1, SARS-CoV, MERS-CoV, and SARS-CoV-2). This novel antigen is expected to induce strong CTL responses with broad coverage by targeting conserved epitopes against multiple coronaviruses.

Characterizing the spatial transmission pattern is critical for better surveillance and control of human influenza. Here, we propose a mutation network framework that utilizes network theory to study the transmission of human influenza H3N2. On the basis of the mutation network, the transmission analysis captured the circulation pattern from a global simulation of human influenza H3N2. Furthermore, this method was applied to explore, in detail, the transmission patterns within Europe, the United States, and China, revealing the regional spread of human influenza H3N2. The mutation network framework proposed here could facilitate the understanding, surveillance, and control of other infectious diseases.

Jinfeng Zeng1*, Fang Yang1*, Wei Zhang2, Qimei Gong1, Yu Du1, Junqi Ling11Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology and Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, China; 2National Neuroscience Institute, Singapore *These authors contributed equally to this workAbstract: The etiology of dental pulp stones, one type of extraskeletal calcification disease, remains elusive to date. Calcifying nanoparticles (CNPs), formerly referred to as nanobacteria, were reported to be one etiological factor in a number of extraskeletal calcification diseases. We hypothesized that CNPs are involved in the calcification of the dental pulp tissue, and therefore investigated the link between CNPs and dental pulp stones. Sixty-five freshly collected dental pulp stones, each from a different patient, were analyzed. Thirteen of the pulp stones were examined for the existence of CNPs in situ by immunohistochemical staining (IHS), indirect immunofluorescence staining (IIFS), and transmission electron microscope (TEM). The remaining 52 pulp stones were used for isolation and cultivation of CNPs; the cultured CNPs were identified and confirmed via their shape and growth characteristics. Among the dental pulp stones examined in situ, 84.6% of the tissue samples staines positive for CNPs antigen by IHS; the corresponding rate by IIFS was 92.3 %. In 88.2% of the cultured samples, CNPs were isolated and cultivated successfully. The CNPs were visible under TEM as 200–400 nm diameter spherical particles surrounded by a compact crust. CNPs could be detected and isolated from a high percentage of dental pulp stones, suggesting that CNPs might play an important role in the calcification of dental pulp.Keywords: calcifying nanoparticles, nanobacteria, pulp stones

Fang Yang1,4, Jinfeng Zeng1,4, Wei Zhang2, Xi Sun3, Junqi Ling11Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology and Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, China; 2National Neuroscience Institute, Singapore; 3School of Biological Engineering, Tianjin University of Science and Technology, Tianjin, China; 4These authors contributed equally to this workAbstract: Calcifying nanoparticles (CNPs, previously called nanobacteria) are self-propagating, cultivable macromolecular complexes. Their extraordinary characteristic is that they can aggregate carbonate apatite on their envelope from soluble calcium and phosphorus at physiologic concentrations and display cytotoxic effects on murine and human fibroblast cell lines. The question arises whether CNPs contribute to the degeneration of pulp tissue and thus result in clinically significant human dental pulp stones as nidies. This study evaluates CNPs' effects upon human dental pulp cells (HDPCs, the host cells in pulp tissue). We observed the ultrastructural variation of HDPCs attacked by CNPs. The spatial relationship of HDPCs and CNPs after coculture was also identified by immunofluroscence staining. Furthermore, it was verified by MTT viability assay that CNPs isolated from dental pulp stones exerted cytotoxic effect on HDPCs. Therefore, it could be concluded that the existence of CNPs might interfere with the normal physiologic function of the cells, and that might lead to dental pulp calcification. Elucidation of the cytotoxic characteristics of CNPs may offer a new perspective for understanding the etiology of human dental pulp stones.Keywords: calcifying nanoparticles, nanobacteria, human dental pulp cells

Nonstructural protein 3 (NS3) of hepatitis C virus (HCV), codes for protease and helicase carrying NTPase enzymatic activities, plays a crucial role in viral replication and an ideal target for diagnosis, antiviral therapy and vaccine development. In this study, monoclonal antibodies (mAbs) to NS3 helicase were characterized by epitope mapping and biological function test. A total of 29 monoclonal antibodies were produced to the truncated NS3 helicase of HCV-1b (T1b-rNS3, aa1192-1459). Six mAbs recognized 8/29 16mer peptides, which contributed to identify 5 linear and 1 discontinuous putative epitope sequences. Seven mAbs reacted with HCV-2a JFH-1 infected Huh-7.5.1 cells by immunofluorescent staining, of which 2E12 and 3E5 strongly bound to the exposed linear epitope (1231)PTGSGKSTK(1239) (EP05) or core motif (1373)IPFYGKAI(1380) (EP21), respectively. Five other mAbs recognized semi-conformational or conformational epitopes of HCV helicase. MAb 2E12 binds to epitope EP05 at the ATP binding site of motif I in domain 1, while mAb 3E5 reacts with epitope EP21 close to helicase nucleotide binding region of domain 2. Epitope EP05 is totally conserved and EP21 highly conserved across HCV genotypes. These two epitope peptides reacted strongly with 59-79% chronic and weakly with 30-58% resolved HCV infected blood donors, suggesting that these epitopes were dominant in HCV infection. MAb 2E12 inhibited 50% of unwinding activity of NS3 helicase in vitro. Novel monoclonal antibodies recognize highly conserved epitopes at crucial functional sites within NS3 helicase, which may become important antibodies for diagnosis and antiviral therapy in chronic HCV infection.

Silver nanowires-silver nanoparticles-graphene nanosheets (AgNWs-AgNPs-GN) hybrid nanomaterials were fabricated through a hydrothermal method by using glucose as a green reducing agent. The charge carriers of AgNWs-AgNPs-GN passed through defect regions in the GNs rapidly with the aid of the AgNW and AgNP building blocks, leading to high electrical conductivity of electrically conductive adhesives (ECA) filled with AgNWs-AgNPs-GN. The morphologies of synthesized AgNWs-AgNPs-GN hybrid nanomaterials were characterized by field emission scanning electron microscope (FESEM), and high resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) and laser confocal micro-Raman spectroscopy were used to investigate the structure of AgNWs-AgNPs-GN. The resistance of cured ECAs was investigated by the four-probe method. The results indicated AgNWs-AgNPs-GN hybrid nanomaterials exhibited excellent electrical properties for decreasing the resistivity of electrically conductive adhesives (ECA). The resistivity of ECA was 3.01 × 10−4 Ω·cm when the content of the AgNWs-AgNPs-GN hybrid nanomaterial was 0.8 wt %.

Since 2020, clade 2.3.4.4b highly pathogenic avian influenza H5N8 and H5N1 viruses have swept through continents, posing serious threats to the world. Through comprehensive analyses of epidemiological, genetic, and bird migration data, we found that the dominant genotype replacement of the H5N8 viruses in 2020 contributed to the H5N1 outbreak in the 2021/2022 wave. The 2020 outbreak of the H5N8 G1 genotype instead of the G0 genotype produced reassortment opportunities and led to the emergence of a new H5N1 virus with G1's HA and MP genes. Despite extensive reassortments in the 2021/2022 wave, the H5N1 virus retained the HA and MP genes, causing a significant outbreak in Europe and North America. Furtherly, through the wild bird migration flyways investigation, we found that the temporal-spatial coincidence between the outbreak of the H5N8 G1 virus and the bird autumn migration may have expanded the H5 viral spread, which may be one of the main drivers of the emergence of the 2020-2022 H5 panzootic. [ABSTRACT FROM AUTHOR]