Objective: To analyze the epidemiological characteristics and influencing factors of severe fever with thrombocytopenia syndrome (SFTS) in Zhejiang Province from 2019 to 2023, so as to provide the reference for strengthening SFTS prevention and control. Methods: Data on laboratory-confirmed SFTS cases in Zhejiang Province from 2019 to 2023 were collected through the Infectious Disease Reporting Information System of Chinese Disease Prevention and Control Information System. Meteorological data, geographic environment and socioeconomic factors during the same period were collected from the fifth-generation European Centre for Medium-Range Weather Forecasts, Geospatial Data Cloud, and Zhejiang Statistical Yearbook, respectively. Descriptive epidemiological methods were used to analyze the epidemiological characteristics of SFTS from 2019 to 2023, and a Bayesian spatio-temporal model was constructed to analyze the influencing factors of SFTS incidence. Results: A total of 578 SFTS cases were reported in Zhejiang Province from 2019 to 2023, with an annual average incidence of 0.23/105. The peak period was from May to July, accounting for 52.60%. There were 309 males and 269 females, with a male-to-female ratio of 1.15∶1. The cases were mainly aged 50-<80 years, farmers, and in rural areas, accounting for 82.53%, 77.34%, and 75.43%, respectively. Taizhou City and Shaoxing City reported more SFTS cases, while Shaoxing City and Zhoushan City had higher annual average incidences of SFTS. The Bayesian spatio-temporal interaction model showed good goodness of fit. The results showed that mean temperature (RR=1.626, 95%CI: 1.111-2.378) and mean wind speed (RR=1.814, 95%CI: 1.321-2.492) were positively correlated with SFTS risk, while altitude (RR=0.432, 95%CI: 0.230-0.829) and population density (RR=0.443, 95%CI: 0.207-0.964) were negatively correlated with SFTS risk. Conclusions SFTS in Zhejiang Province peaks from May to July. Middle-aged and elderly people and farmers are high-risk populations. Taizhou City, Shaoxing City, and Zhoushan City are high-incidence areas. Mean temperature, mean wind speed, altitude, and population density can all affect the risk of SFTS incidence.

ObjectiveThis paper aims to observe the role of Danlou tablet in treating coronary heart disease （CHD） with phlegm-stasis intermingling syndrome in minipigs by improving platelet function and explore the potential pharmacological mechanism of Danlou tablet in regulating platelet function by using proteomics technology. MethodsThirty Bama minipigs were randomly divided into a normal control group （6 pigs） and a high-fat diet group （24 pigs）. After 2 weeks of high-fat diet feeding， the high-fat diet group was randomly subdivided into a model group， an atorvastatin group （1 mg·kg^-1）， and Danlou tablet groups （0.6 g·kg^-1 and 0.3 g·kg^-1）. All groups continued to receive a high-fat diet for 8 weeks after the procedure. The normal control group was given a regular diet， underwent only coronary angiography， and did not receive an interventional injury procedure. The model group and each administration group were fed a high-fat diet. Two weeks later， they underwent a coronary angiography injury procedure. After the procedure， drugs were mixed into the feed every morning for 8 consecutive weeks， with the minipigs maintained on a continuous high-fat diet during this period. Quantitative proteomics technology was further used to study platelet proteins， and differential proteins were obtained by screening. Bioinformatics analysis was performed to analyze key regulatory proteins and biological pathways involved in the therapeutic effect of Danlou tablet on CHD with phlegm-stasis intermingling syndrome. ResultsCompared with the normal control group， the model group showed a significant increase in total cholesterol （TC）， triglyceride （TG）， high-density lipoprotein cholesterol （HDL-C）， and low-density lipoprotein cholesterol （LDL-C） of minipigs' serum （P<0.01）， a significant shortening in prothrombin time of （PT） （P<0.01）， a coagulation function index， and an increase in whole blood viscosity （P<0.01） and platelet aggregation rate （P<0.01）. Moreover， the platelet morphology was altered， and the contents of endothelin-1 （ET-1） and nitric oxide （NO） were significantly increased （P<0.01）. Hemodynamic parameters were obviously abnormal， including significantly decreased systolic blood pressure （SBP）， diastolic blood pressure （DBP）， mean arterial pressure （MAP）， left ventricular systolic pressure （LVSP）， and left ventricular maximal positive dp/dt （LV+dp/dt_max） （P<0.01）. Left ventricular maximal negative dp/dt （LV-dp/dt_max） was significantly increased （P<0.01）. Besides， there were myocardial cell hypertrophy， obvious edematous degeneration， massive interstitial inflammatory cell infiltration， high degree of fibrosis， and coronary endothelial atherosclerosis. TC and TG levels in minipigs' serum were significantly reduced in Danlou tablet groups with 0.6 g·kg^-1 and 0.3 g·kg^-1 （P<0.05， P<0.01）， compared with those in the model group. LDL-C was decreased in the Danlou tablet group with 0.6 g·kg^-1 （P<0.05）. The whole blood viscosity under low and high shear conditions was significantly reduced in the Danlou tablet group with 0.6 g·kg^-1 （P<0.05）. In groups with all doses of Danlou tablet， maximum aggregation rate （MAR） and average aggregation rate （AAR） were significantly decreased （P<0.05， P<0.01）， and platelets' morphological changes such as pseudopodia extension were reduced. ET-1 levels in the serum were significantly reduced. In the Danlou tablet group with 0.6 g·kg^-1， NO level in the serum was reduced （P<0.05）. In groups with all doses of Danlou tablet， DBP and MAP were significantly increased （P<0.05）. In the Danlou tablet group with 0.6 g·kg^-1， LVSP and LV+dp/dt_max were significantly increased （P<0.05， P<0.01）， and LV-dp/dt_max was significantly decreased （P<0.05）. In groups with all doses of Danlou tablet， edematous degeneration in myocardial tissue was milder， and coronary artery lesion degree was significantly alleviated. Compared with the normal control group， there were 94 differentially expressed proteins in the model group， including 81 up-regulated and 13 down-regulated proteins. Compared with the model group， the Danlou tablet group with 0.6 g·kg^-1 showed 174 differentially expressed proteins， including 100 up-regulated and 74 down-regulated proteins. A total of 30 proteins were reversed after Danlou tablet intervention. Bioinformatics analysis revealed that its pharmacological mechanism may exert anti-platelet activation， aggregation， and adhesion effects through biological pathways such as regulation of actin cytoskeleton， platelet activation pathway， Fcγ receptor-mediated phagocytosis， as well as proteins such as growth factor receptor-bound protein 2 （GRB2）， Ras-related C3 botulinum toxin substrate 2 （RAC2）， RAC1， and heat shock protein 90 alpha family class A member 1 （HSP90AA1）. ConclusionDanlou tablet can effectively reduce platelet activation and aggregation， exerting a good therapeutic effect on CHD with phlegm-stasis intermingling syndrome in minipigs. Its pharmacological mechanism may involve regulating biological pathways such as actin cytoskeleton and platelet activation pathway， as well as proteins like GRB2， RAC2， RAC1， and HSP90AA1， thereby exerting a pharmacological effect in anti-platelet activation， aggregation， and adhesion.

BACKGROUND:Buqi Huoxue Compounds have significant clinical efficacy in treating ischemic stroke with Qi deficiency and phlegm stasis;however,the exact mechanism of action is not clear. OBJECTIVE:To observe the effect of Buqi Huoxue Compounds on the expression of vascular endothelial growth factor,basic fibroblast growth factor,brain-derived neurotrophic factor and autophagy related protein Beclin1 and p62 in a rat model of cerebral ischemia/reperfusion. METHODS:Forty male Sprague-Dawley rats were randomly divided into sham operation group,model group,Buqi Huoxue Compounds group and autophagy inhibitor group,with 10 rats in each group.In the latter three groups,a rat model of cerebral ischemia/reperfusion injury was established.The Buqi Huoxue Compounds group was intragastrically given Buqi Huoxue Compounds(6.49 g/kg,administered three times a day)2 hours after reperfusion;the autophagy inhibitor group was intragastrically given Buqi Huoxue Compounds(6.49 g/kg,administered three times a day)2 hours after reperfusion and intraperitoneally given 3-methyladenine 2 hours before gavage and at days 1-3 of gavage.The sham operation group and model group were given equal amounts of saline by gavage for 7 consecutive days.Neurological function,cerebral infarct volume,brain tissue morphology and expression of vascular endothelial growth factor,basic fibroblast growth factor,brain-derived neurotrophic factor and autophagy-related proteins Beclin1 and p62 in the ischemic cortical region of rats were detected at 24 hours after the final administration. RESULTS AND CONCLUSION:Zea-Longa scoring results showed that the neurological function of rats was severely damaged after modeling and neurological deficit of rats in the Buqi Huoxue Compounds group was less than that in the model group and the autophagy inhibitor group(P＜0.05).TTC staining showed that cerebral infarct foci were observed in the model group,Buqi Huoxue Compounds group,and autophagy inhibitor group,and the cerebral infarct volume in the Buqi Huoxue Compounds group was lower than that in the model group and the autophagy inhibitor group(P＜0.05).The results of hematoxylin-eosin staining in ischemic brain tissues showed that there were large gaps between nerve cells in the model group and cell arrangement was not neat,and cytoplasmic agglutination and pyknosis were observed.Immunohistochemical staining results showed that vascular endothelial growth factor was mostly expressed in neuronal cells,glial cells and capillary endothelium;basic fibroblast growth factor and brain-derived neurotrophic factor were mostly expressed in neuronal cells and glial cells;and there was no significant difference in the expression of vascular endothelial growth factor,basic fibroblast growth factor,and brain-derived neurotrophic factor among the four groups(P＞0.05).The results of western blot assay showed that compared with the sham operation group,Beclin1 protein expression was decreased(P＜0.05)and p62 protein expression was elevated(P＜0.05)in the model group;compared with the model group,Beclin1 protein expression was increased(P＜0.05)and p62 protein expression was reduced(P＜0.05)in the Buqi Huoxue Compounds group;compared with the Buqi Huoxue Compounds group,Beclin1 protein expression was decreased(P＜0.05)and p62 protein expression was elevated(P＜0.05)in the autophagy inhibitor group.To conclude,Buqi Huoxue Compounds attenuate cerebral ischemia-reperfusion injury in rats by promoting autophagy.

BackgroundNon-suicidal self-injury （NSSI） behaviors are prevalent among adolescents， significantly affecting their physical and mental well-being. Understanding the risk factors associated with adolescent NSSI is crucial for prevention. Previous studies have identified mobile phone dependence as a risk factor for NSSI in adolescents. However， as a key form of mobile phone dependence， the evidence regarding the impact of mobile phone social media dependence on adolescent NSSI behavior remains insufficient. ObjectiveTo explore the impact of mobile phone social media dependence and its associated factors on adolescent NSSI behavior， so as to provide references for intervention strategies targeting NSSI in adolescents. MethodsA total of 100 adolescents diagnosed with NSSI according to the Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5）， and receiving treatment at Tongde Hospital of Zhejiang Province from January 2022 to December 2023 were included in the study group. Concurrently， 100 age- and sex-matched students from Hangzhou were recruited as the control group. Assessments were conducted using Ottawa Self-injury Inventory（OSI） Function Subscale and Addiction Features Subscale， Adolescents Self-Harm Scale（ASHS）， and Mobile Phone Social Media Dependence Questionnaire. Multiple linear regression was used to analyze the factors influencing NSSI behaviors. ResultsThe research group had a total of 99 patients （99.00%） who completed the study， while the control group consisted of 97 （97.00%） adolescents who finished this research.The study group had statistically significantly higher total scores on the Mobile Phone Social Media Dependence Questionnaire， as well as higher scores on the conflict and withdrawal dimensions， compared with control group（t=-3.061， -2.874， -2.368， P<0.05 or 0.01）. The study group also scored significantly higher on the OSI Function Subscale for internal emotion regulation， social influence， external emotion regulation， and sensation-seeking factors， as well as on the OSI Addiction Features Subscale scores， compared to the control group（t=-22.249， -8.854， -17.968， -10.591， -20.157， P<0.01）. OSI Function Subscale scores were positively correlated with Mobile Phone Social Media Dependence Questionnaire scores （r=0.321， P<0.01）， and OSI Addiction Features Subscale scores were positively correlated with Mobile Phone Social Media Dependence Questionnaire scores （r=0.282， P<0.01）. ASHS scores were positively correlated with Mobile Phone Social Media Dependence Questionnaire scores （r=0.145， P<0.05）. Multiple linear regression analysis showed that compulsivity （β=0.416， P<0.01） and conflict （β=0.256， P<0.05） were significant predictors for adolescent NSSI behaviors. ConclusionAdolescent NSSI behaviors are associated with mobile phone social media dependence. The compulsivity and conflict dimension of mobile phone social media dependence are influencing factors for adolescent NSSI behaviors. The higher level of the compulsivity and conflict are associated with an increased risk of the NSSI behaviors in adolescents. ［Funde by Zhejiang Medical and Health Science and Technology Plan Project in 2022 （number， 2022KY704］

Objective: To analyze the nucleic acid load of human parvovirus B19 in major commercially available blood products in China, including human albumin, human intravenous immunoglobulin, human rabies immunoglobulin and various coagulation factor products, aiming to provide evidence for improving blood product manufacturing processes and quality control of source plasma. Methods: A total of 98 batches of coagulation factor products were tested for human parvovirus B19 nucleic acid using real-time fluorescent quantitative PCR, including 42 batches of human prothrombin complex, 35 batches of human coagulation factor Ⅷ, and 21 batches of human fibrinogen. Additionally, 6 batches of human albumin, 6 batches of human intravenous immunoglobulin, and 38 batches of human rabies immunoglobulin were tested for human parvovirus B19 nucleic acid. Results: Human parvovirus B19 nucleic acid were undetectable in human albumin, human intravenous immunoglobulin and human rabies immunoglobulin. Among the 98 batches of coagulation factor products tested for human parvovirus B19 nucleic acid, B19 nucleic acid reactivity rate was 69.0% (29/42) for human prothrombin complex batches, but nucleic acid concentration were all significantly lower than 10 IU/mL. The reactivity rate of B19 nucleic acid in 35 batches of human coagulation factor Ⅷ was 48.6% (17/35), with nucleic acid concentration all below 10 IU/mL. The reactivity rate of B19 nucleic acid in 21 batches of human fibrinogen was 61.9% (13/21), with nucleic acid concentration all below 10 IU/mL. Conclusion: No human parvovirus B19 has been detected in human albumin, human intravenous immunoglobulin, or human rabies immunoglobulin. Human parvovirus B19 nucleic acid may exist in commercially available coagulation factor products, highlighting the need for enhanced screening of human parvovirus B19 nucleic acid in these products. It is also recommended that B19 viral nucleic acid testing be conducted on source plasma, particularly for coagulation factor products.

Objective: To analyze the nucleic acid load of human parvovirus B19 in major commercially available blood products in China, including human albumin, human intravenous immunoglobulin, human rabies immunoglobulin and various coagulation factor products, aiming to provide evidence for improving blood product manufacturing processes and quality control of source plasma. Methods: A total of 98 batches of coagulation factor products were tested for human parvovirus B19 nucleic acid using real-time fluorescent quantitative PCR, including 42 batches of human prothrombin complex, 35 batches of human coagulation factor Ⅷ, and 21 batches of human fibrinogen. Additionally, 6 batches of human albumin, 6 batches of human intravenous immunoglobulin, and 38 batches of human rabies immunoglobulin were tested for human parvovirus B19 nucleic acid. Results: Human parvovirus B19 nucleic acid were undetectable in human albumin, human intravenous immunoglobulin and human rabies immunoglobulin. Among the 98 batches of coagulation factor products tested for human parvovirus B19 nucleic acid, B19 nucleic acid reactivity rate was 69.0% (29/42) for human prothrombin complex batches, but nucleic acid concentration were all significantly lower than 10 IU/mL. The reactivity rate of B19 nucleic acid in 35 batches of human coagulation factor Ⅷ was 48.6% (17/35), with nucleic acid concentration all below 10 IU/mL. The reactivity rate of B19 nucleic acid in 21 batches of human fibrinogen was 61.9% (13/21), with nucleic acid concentration all below 10 IU/mL. Conclusion: No human parvovirus B19 has been detected in human albumin, human intravenous immunoglobulin, or human rabies immunoglobulin. Human parvovirus B19 nucleic acid may exist in commercially available coagulation factor products, highlighting the need for enhanced screening of human parvovirus B19 nucleic acid in these products. It is also recommended that B19 viral nucleic acid testing be conducted on source plasma, particularly for coagulation factor products.

ObjectiveTo investigate the influence of empagliflozin combined with donafenib or lenvatinib on the pharmacokinetic parameters of each drug， and to provide a reference for combined medication in clinical practice. MethodsA total of 48 healthy male Sprague-Dawley rats were divided into 8 groups： empagliflozin group 1 and 2， donafenib group， lenvatinib group， donafenib pretreatment+empagliflozin group， lenvatinib pretreatment + empagliflozin group， empagliflozin pretreatment+donafenib group， and empagliflozin pretreatment+lenvatinib group， with 6 rats in each group. The doses of empagliflozin， donafenib， and lenvatinib were 2.5 mg/kg， 40 mg/kg， and 1.2 mg/kg， respectively. The rats in the empagliflozin group， donafenib group， and lenvatinib group were given a blank solvent by gavage for 7 consecutive days， followed by a single dose of empagliflozin， donafenib， or lenvatinib on day 7 after the administration of the blank solvent； the rats in the pretreatment groups were given the pretreatment drug by gavage for 7 consecutive days， followed by a single dose of drug combination on day 7 after administration of the pretreatment drug. Blood samples were collected at different time points， and plasma was separated to measure the concentration of each drug. A validated ultra-performance liquid chromatography-tandem mass spectrometry method was used to measure the plasma concentrations of donafenib， lenvatinib， and empagliflozin， and a non-compartmental model was used to calculate the main pharmacokinetic parameters of each drug （area under the plasma concentration-time curve ［AUC］， time to peak ［T_max］， peak concentration ［C_max］， and half-life time ［t_1/2］）. The independent-samples t test was used for comparison of normally distributed continuous data between two groups， and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups. ResultsCompared with the empagliflozin group， the donafenib pretreatment+empagliflozin group had significant increases in the AUC_0-t and AUC_0-∞ of empagliflozin （P=0.011 and 0.008）， while the lenvatinib pretreatment+empagliflozin group had no significant change in the AUC of empagliflozin， with a slightly shorter T_max （P=0.019）. Compared with the donafenib group， the empagliflozin pretreatment+donafenib group had significant increases in the AUC_0-t and AUC_0-∞ of donafenib （P=0.027 and 0.025）， as well as a significant increase in C_max （P=0.015） and significant reductions in CLz/F and Vz/F （P=0.005 and 0.004）； compared with the lenvatinib group， the empagliflozin pretreatment+lenvatinib group had a reduction in the t_1/2 of lenvatinib by approximately 5 hours （P=0.002）， with a trend of reduction in AUC_0-t （P0.05）. ConclusionEmpagliflozin combined with donafenib may alter the pharmacokinetic parameters of both drugs， leading to a significant increase in the exposure levels of both drugs， and efficacy and adverse reactions should be monitored during co-administration. There are no significant changes in the exposure levels of empagliflozin and lenvatinib during co-administration.

ObjectiveTo explore the mechanism of the Wenyang Jieyu prescription in regulating depression-like behavior in mice after maternal-infant separation combined with secondary stress. MethodsAfter birth， the rats were randomly divided into blank （NC） group， maternal-infant separation （MS） group， restraint stress （RS） group， maternal-infant separation combined with restraint stress （MRS） group， Wenyang group， Jieyu group， Wenyang Jieyu （XSF） group， and minocycline group. Maternal-infant separation was performed on day 5 （PD5）， followed by weaning at PD21 and prophylactic administration. The dose of Wenyang group， Xiaoyao group， XSF group and minocycline group were 5.85， 12.03， 16.71 g·kg^-1 and 50 mg·kg^-1， respectively. Restraint stress was applied on PD90. The model was evaluated using glucose， social interaction， open field， and O-maze behavior tests， as well as high-performance liquid chromatography to measure serotonin， dopamine， and other neurotransmitters. The expression level of ionized calcium-binding adaptor molecule-1 （Iba-1） protein， a marker of hippocampal microglia， was detected by immunohistochemistry. Protein expression levels of Janus kinase 2 （JAK2） and signal transducer and activator of transcription 3 （STAT3） in the hippocampus were analyzed by an automatic protein expression analysis system. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect mRNA expression levels of M1 markers， JAK2/STAT3 pathway-related genes， and cytokines in hippocampal microglia in each group. ResultsCompared with the NC group， the MRS group exhibited depression-like behavior， with significantly decreased levels of neurotransmitters in the hippocampus （P<0.05， P<0.01）， increased expression of Iba-1 （P<0.01）， and elevated protein levels of JAK2 and STAT3 （P<0.05）. The mRNA expression levels of CD68， CD11b， IL-1β， JAK2， and STAT3 were significantly increased （P<0.01）， while IL-10 mRNA expression was significantly decreased （P<0.01）. Compared with the MRS group， the XSF and minocycline groups showed some improvement in depression-like behavior. In these groups， the hippocampal neurotransmitter content was significantly increased （P<0.05， P<0.01）， and Iba-1 expression was significantly decreased （P<0.01）. The protein levels of JAK2 and STAT3 in the XSF group showed a downward trend. The mRNA expression levels of CD68， CD11b， JAK2， STAT3， and IL-1β in the hippocampus were significantly decreased in the XSF and minocycline groups （P<0.05， P<0.01）， while IL-10 mRNA expression was significantly increased （P<0.05， P<0.01）. ConclusionWenyang Jieyu prescription can regulate depression-like behavior in maternal-infant separation mice combined with secondary stress by inhibiting the polarization of hippocampal microglia to the M1 phenotype. The regulation of hippocampal microglia polarization by Wenyang Jieyu prescription may be associated with the JAK2/STAT3 pathway.

AIM: To observe the manifestations and distribution patterns of visual field in non-arteritic anterior ischemic optic neuropathy(NAION).METHODS: Retrospective observational study. The investigation encompassed 183 patients(246 eyes)diagnosed with NAION who were evaluated at the Neuro-Ophthalmology/Acupuncture Department within the Eye Hospital, China Academy of Chinese Medical Sciences from June 2018 to December 2023. Recorded clinical data covered demographic details, incidence, disease duration, presence of systemic diseases, and histories of tobacco and alcohol use, along with best-corrected visual acuity(BCVA), visual field index(VFI), type of visual field defect, and thickness of the peripapillary retinal nerve fiber layer(pRNFL).RESULTS: A total of 183 patients(246 eyes)were enrolled. The cohort consisted of 101 males and 82 females; 120 exhibited unilateral symptoms, while 63 showed bilateral symptoms, with a mean age of 56.20±9.78 years(range 29-81 years). The types of visual field defects observed were varied: 90 eyes(36.6%)had diffuse loss, 63 eyes(25.6%)experienced inferior hemifield loss, 32 eyes(13.0%)displayed ring scotomas, 22 eyes(8.9%)had arcuate scotomas, 11 eyes(4.5%)presented with quadrant defects, 15 eyes(6.1%)had sectorial or wedge defects, and 13 eyes(5.3%)showed superior hemifield loss. The BCVA(LogMAR)and VFI of patients with diffuse visual field loss were poorer than patients with other types of visual defects(all P<0.05). There were statistically significant differences in visual field defects among patients of different genders and ages(all P<0.05). However, history of hypertension, diabetes, hyperlipidemia, sleep apnea and other systemic diseases, history of smoking and alcohol, and course of disease did not show specificity in the NAION visual field(all P>0.05).CONCLUSION:NAION manifests with a broad spectrum of visual field impairments across different genders, age, and levels of visual functionality. Extensive future research is necessary to identify additional reasons influencing the types of visual field damage in NAION.

ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.