ObjectiveTo observe the effects of Yiqi Huoxue Jiedu formula（YHJF） on immune cell exhaustion in the spleen of septic mice and to explore and validate its potential intervention targets. MethodsMice were randomly divided into the sham-operated， model， low-dose YHJF（4.1 g·kg^-1）， and high-dose YHJF（8.2 g·kg^-1） groups. Except for the sham-operated group， a cecal ligation and puncture（CLP） procedure was performed to establish a mouse sepsis model. The treatment groups received oral administration of the corresponding doses， while the sham-operated and model groups received an equal volume of physiological saline. After the intervention， the 7-day survival rate of each group was recorded， and spleen samples were collected 72 h post-intervention， and the spleen index was calculated. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate（dUTP） nick end labeling（TUNEL） staining was used to detect apoptosis in spleen cells. Enzyme-linked immunosorbent assay（ELISA） was performed to measure the levels of interleukin（IL）-4 and IL-10 in the serum. Transcriptomics and metabolomics were used to screen for differentially expressed genes（DEGs） and differential metabolites in the spleen， followed by bioinformatics analysis to identify key targets. Real-time quantitative polymerase chain reaction（Real-time PCR）， flow cytometry， and multiplex immunofluorescence were used to verify the expressions of key genes and proteins. ResultsThe high-dose YHJF group significantly improved the 7-day survival rate of septic mice（P0.05）. Compared with the sham-operated group， the model group showed a significant increase in apoptosis of spleen cells and a decrease in the spleen index at 72 h post-modeling， with markedly elevated peripheral serum IL-4 and IL-10 levels（P0.01）. Compared with the model group， the high-dose YHJF group showed a reduction in apoptosis of spleen cells， an increase in the spleen index， and a significant decrease in peripheral serum IL-4 and IL-10 levels（P0.05）. Spleen transcriptomics identified 255 DEGs between groups， potentially serving as intervention targets for YHJF. Gene Ontology（GO） enrichment analysis revealed that DEGs were mainly involved in biological processes such as natural killer（NK） cell-mediated positive immune regulation， cell killing， cytokine production， positive regulation of innate immune cells， and interferon production. Kyoto Encyclopedia of Genes and Genomes（KEGG） pathway enrichment analysis showed that DEGs were mainly involved in cytokine-cytokine receptor interactions， viral protein interactions with cytokines and cytokine receptors， chemokine signaling pathway， and nuclear transcription factor-κB（NF-κB） signaling pathway. Protein-protein interaction（PPI） network analysis identified CD160， granzyme B（GZMB）， and chemokine ligand 4（CCL4） as key targets for YHJF in treating sepsis. Metabolomics identified 46 differential metabolites that were significantly reversed by YHJF intervention， and combined transcriptomics and metabolomics analysis identified 17 differential metabolites closely related to CD160. Pathway enrichment revealed that these metabolites were mainly involved in glycerophospholipid metabolism， arachidonic acid metabolism， glycosylphosphatidylinositol（GPI） anchor biosynthesis， linoleic acid metabolism， and α-linolenic acid metabolism pathways. Verification results showed that， compared with the sham-operated group， the model group exhibited significantly elevated CD160 mRNA expression level in the spleen， along with markedly decreased CCL4 and GZMB mRNA expression， and had a significant increase in CD160 expression on the surface of natural killer T（NKT） cells in the spleen（P0.01）. Compared with the model group， the high-dose YHJF group had a significant decrease in CD160 mRNA expression in the spleen， a significant increase in CCL4 and GZMB mRNA expressions. Further flow cytometry and immunofluorescence revealed that compared with the sham-operated group， CD160 expression on the surface of splenic NKT cells in the model group was significantly increased（P0.01）， while high-dose YHJF intervention significantly reduced CD160 expression（P0.01）. ConclusionYHJF may alleviate NKT cell exhaustion in sepsis by downregulating the expression of the negative co-stimulatory molecule CD160， and this regulatory effect is closely related to fatty acid metabolism pathways. This study provides new insights and targets for further exploration of strengthening vital Qi and detoxifying strategy to improve immune cell exhaustion in acute deficiency syndrome of sepsis.

ObjectiveTo observe the effects of Yiqi Huoxue Jiedu formula（YHJF） on immune cell exhaustion in the spleen of septic mice and to explore and validate its potential intervention targets. MethodsMice were randomly divided into the sham-operated， model， low-dose YHJF（4.1 g·kg^-1）， and high-dose YHJF（8.2 g·kg^-1） groups. Except for the sham-operated group， a cecal ligation and puncture（CLP） procedure was performed to establish a mouse sepsis model. The treatment groups received oral administration of the corresponding doses， while the sham-operated and model groups received an equal volume of physiological saline. After the intervention， the 7-day survival rate of each group was recorded， and spleen samples were collected 72 h post-intervention， and the spleen index was calculated. Terminal deoxynucleotidyl transferase deoxyuridine triphosphate（dUTP） nick end labeling（TUNEL） staining was used to detect apoptosis in spleen cells. Enzyme-linked immunosorbent assay（ELISA） was performed to measure the levels of interleukin（IL）-4 and IL-10 in the serum. Transcriptomics and metabolomics were used to screen for differentially expressed genes（DEGs） and differential metabolites in the spleen， followed by bioinformatics analysis to identify key targets. Real-time quantitative polymerase chain reaction（Real-time PCR）， flow cytometry， and multiplex immunofluorescence were used to verify the expressions of key genes and proteins. ResultsThe high-dose YHJF group significantly improved the 7-day survival rate of septic mice（P0.05）. Compared with the sham-operated group， the model group showed a significant increase in apoptosis of spleen cells and a decrease in the spleen index at 72 h post-modeling， with markedly elevated peripheral serum IL-4 and IL-10 levels（P0.01）. Compared with the model group， the high-dose YHJF group showed a reduction in apoptosis of spleen cells， an increase in the spleen index， and a significant decrease in peripheral serum IL-4 and IL-10 levels（P0.05）. Spleen transcriptomics identified 255 DEGs between groups， potentially serving as intervention targets for YHJF. Gene Ontology（GO） enrichment analysis revealed that DEGs were mainly involved in biological processes such as natural killer（NK） cell-mediated positive immune regulation， cell killing， cytokine production， positive regulation of innate immune cells， and interferon production. Kyoto Encyclopedia of Genes and Genomes（KEGG） pathway enrichment analysis showed that DEGs were mainly involved in cytokine-cytokine receptor interactions， viral protein interactions with cytokines and cytokine receptors， chemokine signaling pathway， and nuclear transcription factor-κB（NF-κB） signaling pathway. Protein-protein interaction（PPI） network analysis identified CD160， granzyme B（GZMB）， and chemokine ligand 4（CCL4） as key targets for YHJF in treating sepsis. Metabolomics identified 46 differential metabolites that were significantly reversed by YHJF intervention， and combined transcriptomics and metabolomics analysis identified 17 differential metabolites closely related to CD160. Pathway enrichment revealed that these metabolites were mainly involved in glycerophospholipid metabolism， arachidonic acid metabolism， glycosylphosphatidylinositol（GPI） anchor biosynthesis， linoleic acid metabolism， and α-linolenic acid metabolism pathways. Verification results showed that， compared with the sham-operated group， the model group exhibited significantly elevated CD160 mRNA expression level in the spleen， along with markedly decreased CCL4 and GZMB mRNA expression， and had a significant increase in CD160 expression on the surface of natural killer T（NKT） cells in the spleen（P0.01）. Compared with the model group， the high-dose YHJF group had a significant decrease in CD160 mRNA expression in the spleen， a significant increase in CCL4 and GZMB mRNA expressions. Further flow cytometry and immunofluorescence revealed that compared with the sham-operated group， CD160 expression on the surface of splenic NKT cells in the model group was significantly increased（P0.01）， while high-dose YHJF intervention significantly reduced CD160 expression（P0.01）. ConclusionYHJF may alleviate NKT cell exhaustion in sepsis by downregulating the expression of the negative co-stimulatory molecule CD160， and this regulatory effect is closely related to fatty acid metabolism pathways. This study provides new insights and targets for further exploration of strengthening vital Qi and detoxifying strategy to improve immune cell exhaustion in acute deficiency syndrome of sepsis.

Based on spleen deficiency-phlegm dampness as the core pathogenesis of obesity， and integrating recent advances in modern medicine regarding the key role of immune inflammation in obesity， this paper proposes a multidimensional pathogenic network of "obesity-spleen deficiency-phlegm dampness-immune imbalance". Various traditional Chinese medicine （TCM） herbs that strengthen the spleen， regulate qi， and resolve phlegm and dampness can treat obesity by improving spleen-stomach transport and transformation， promoting water-damp metabolism， and regulating immune homeostasis. This highlights immune inflammation as an important entry point to elucidate the TCM concepts of "spleen deficiency-phlegm dampness" and the therapeutic principle of "strengthening the spleen and eliminating dampness to treat obesity". By systematically analyzing the intrinsic connection between "spleen deficiency generating dampness， internal accumulation of phlegm dampness" and immune dysregulation in obesity， this paper aims to provide theoretical support for TCM treatment of obesity based on dampness.

ObjectiveTo evaluate the impact of yang-reinforcing and blood-activating therapy on the long-term prognosis for patients with dilated cardiomyopathy （DCM） of yang deficiency and blood stasis syndrome. MethodsA retrospective cohort study was conducted involving 371 DCM patients with yang deficiency and blood stasis syndrome. The yang-reinforcing and blood-activating therapy was defined as the exposure factor. Patients were categorized into exposure group （186 cases） and non-exposure group （185 cases） according to whether they received yang-reinforcing and blood-activating therapy combined with conventional western medicine for 6 months or longer. The follow-up period was set at 48 months， and the Kaplan-Meier survival analysis was used to assess the cumulative incidence of major adverse cardiovascular events （MACE） in both groups. Cox regression analysis was used to explore the impact of yang-reinforcing and blood-activating therapy on the risk of MACE， and subgroup analysis was performed. Changes in traditional Chinese medicine （TCM） syndrome score， left ventricular ejection fraction （LVEF）， left ventricular fractional shortening （LVFS）， left ventricular end-diastolic diameter （LVEDD）， and Minnesota Living with Heart Failure Questionnaire （MLHFQ） score were compared between groups at the time of first combined use of yang-reinforcing and blood-activating therapy （before treatment） and 1 year after receiving the therapy （after treatment）. ResultsMACE occurred in 31 cases （16.67%） in the exposure group and 47 cases （25.41%） in the non-exposure group. The cumulative incidence of MACE in the exposure group was significantly lower than that in the non-exposure group ［HR=0.559， 95%CI（0.361，0.895）， P=0.014］. Cox regression analysis showed that yang-reinforcing and blood-activating therapy was an independent factor for reducing the risk of MACE in DCM patients ［HR=0.623， 95%CI（0.396，0.980）， P=0.041］， and consistent results were observed in different subgroups. Compared with pre-treatment， the exposure group showed decreased TCM syndrome score and MLHFQ score， reduced LVEDD， and increased LVEF and LVFS after treatment （P＜0.05）； in the non-exposure group， TCM syndrome score decreased， LVEF and LVFS increased， and LVEDD reduced after treatment （P＜0.05）. After treatment， the exposure group had higher LVEF and LVFS， smaller LVEDD， and lower TCM syndrome score and MLHFQ score compared with the non-exposure group （P＜0.05）. ConclusionCombining yang-reinforcing and blood-activating therapy with conventional western medicine can reduce the risk of MACE in DCM patients with yang deficiency and blood stasis syndrome， meanwhile improving their clinical symptoms， cardiac function， and quality of life.

OBJECTIVE To investigate the mechanism of Xihuang pill （XHP） against diffuse large B-cell lymphoma （DLBCL）. METHODS The active ingredients of XHP and potential therapeutic targets for DLBCL were identified using TCMSP， GeneCards and DisGeNET databases. Protein-protein interaction networks were constructed using the String database and Cytoscape software to screen core components and core targets. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were then performed. The clinical relevance of core targets was analyzed using the GEPIA and PanCanSurvPlot databases. Molecular docking and molecular dynamics （MD） simulation were conducted to verify the interactions between core components and core targets， and the binding free energy was calculated using the molecular mechanics Poisson-Boltzmann surface area （MM-PBSA） method. The effects of XHP on DLBCL and the related molecular mechanisms were validated using CCK-8 assay， flow cytometry and Western blot. RESULTS Network pharmacology analysis identified 108 active ingredients of XHP and 410 potential therapeutic targets for DLBCL. Six core components （e.g.， 17 beta-estradiol， quercetin） and ten core targets [e.g.， tumor protein 53 （TP53）， proto-oncogene tyrosine-protein kinase Src （SRC）] were obtained. Enrichment analysis indicated that the anti-DLBCL effects of XHP were primarily associated with the apoptotic signaling pathway， the phosphoinositide 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway and so on. Clinical correlation analysis revealed that TP53 and SRC expression were significantly up-regulated in DLBCL tissues and associated with poor patient prognosis （P＜0.05）. Molecular docking， MD simulations and MM-PBSA calculations confirmed that the SRC-quercetin complex had a mail：stronger and more stable binding affinity. In vitro experiments demonstrated that XHP concentration-dependently inhibited the proliferation of DLBCL cells； compared with control group， XHP medium- and high-dose groups could significantly induce the apoptosis of SU-DHL2 and SU-DHL4 cells， and significantly down- regulated the expressions of SRC protein， phosphorylated （p）-PI3K/PI3K and p-Akt/Akt in SU-DHL4 cells （P＜0.05）. CONCLUSIONS XHP may inhibit the proliferation and induce the apoptosis of DLBCL cells by regulating the SRC/PI3K/Akt signaling pathway.

OBJECTIVE To evaluate the efficacy and safety of total glucosides of paeonia （TGP） in the treatment of systemic lupus erythematosus （SLE）. METHODS Randomized controlled trial （RCT） about TGP combined with western medicine versus western medicine alone for SLE treatment were retrieved from PubMed， Embase， Cochrane Library， Web of Science， CNKI， VIP， Wanfang Data， and CBM. The search period spanned from the inception of each database to June 1， 2025. After literature screening， data extraction， and quality assessment of the included studies， Meta-analysis was performed using RevMan 5.4 software. RESULTS Fifteen RCTs， involving 1 318 patients， were included. Meta-analysis results showed that compared with western medicine alone， TGP combined with western medicine significantly improved clinical efficacy [OR＝4.96， 95%CI（3.41， 7.23）， P＜0.000 01]， complement 3 [MD＝0.18， 95%CI （0.13， 0.23）， P＜0.000 01] and complement 4[MD＝0.08， 般021） 95%CI （0.04， 0.11）， P＜0.000 01]， and reduced the levels of immunoglobulin G （IgG） [MD＝－3.10， 95%CI （－3.59，－2.62）， P＜0.000 01]， IgA [MD＝－0.68， 95%CI （－0.78， －0.58）， P＜0.000 01]， IgM [MD＝－0.43， 95%CI （－0.53，－0.34）， P＜0.000 01]， systemic lupus erythematosus disease activity index （SLEDAI） [MD＝－1.59， 95%CI （－2.20， －0.99）， P＜0.000 01]， recurrence rate [OR＝0.23， 95%CI （0.13， 0.42）， P＜0.000 01] and the incidence of adverse drug reactions [OR＝ 0.54， 95%CI （0.36， 0.82）， P＝0.004]. CONCLUSIONS TGP therapy can improve clinical efficacy of SLE patients， promote the restoration of immunoglobulins and complements， reduce SLEDAI and recurrence rate and has good safety.

Objective: To explore the association between takeout fast foods and sugar sweetened beverage consumption with co-occurrence of anxiety and depressive symptoms among first year junior high school students in Yunnan Province, so as to provide theoretical basis for the prevention of anxiety and depressive symptoms co-occurrence among adolescents. Methods: A random cluster sampling involving 8 500 first year junior high school students in 11 counties in Yunnan Province was conducted by a questionnaire survey from October to December 2022. The Depression Anxiety Stress Scale-21 (DASS-21) was applied to assess anxiety and depressive symptoms in first year junior high school students. Chi-square test was used to compare the anxiety-depression co-occurrence symptoms of first year junior high school students with different demographic characteristics. The association between takeout fast foods and sugar sweetened beverage consumption with co-occurrence of anxiety and depressive symptoms of adolescents was analyzed by binary Logistic regression models. Results: The detection rate of co-occurrence of anxiety and depression symptoms among first year junior high school students in Yunnan Province was 26.92%. After controlling for demographic variables and other confounders, takeout fast foods and sugar sweetened beverage consumption( OR=1.50, 95%CI =1.27-1.77) was associated with anxiety-depression co-occurrence symptoms among first year junior high school students in Yunnan Province ( P <0.01). Stratified analysis showed that both Han ( OR=1.37, 95%CI =1.07-1.77) and ethnic minorities ( OR=1.60, 95%CI =1.29-2.00) exhibited statistically significant associations between takeout fast foods and sugar sweetened beverage consumption with co-occurrence of anxiety and depressive symptoms(both P <0.05). Conclusions Takeout fast foods and sugar sweetened beverage consumption increases the risk of co-occurrence of anxiety and depressive symptoms among first year junior high school students in Yunnan Province. It is recommended to strengthen guidance on the consumption of such products among junior high school students to prevent co-occurrence of anxiety and depressive symptoms.

Objective: To understand the impact of childhood trauma on psychological distress among upper grade elemetary school students, and to explore the mediating role of leisure activities in the relationship, so as to provide a basis for developing mental health intervention strategies. Methods: From August to November 2024, a combination of convenience sampling and stratified cluster random sampling was employed to recruit 1 373 fourth to sixth grade students from four primary schools in Harbin. The Childhood Trauma Questionnaire(CTQ), a self designed leisure activity scale (including active and passive leisure activities), and the Kessler Psychological Distress Scale (K10) were used to assess childhood trauma experiences, leisure activities, and levels of psychological distress. Spearman correlation analysis and linear regression analysis were conducted to explore the relationships among childhood trauma, leisure types, leisure time, and psychological distress. Based on the mediation analysis framework proposed by Hayes (Model 4), the mediating role of leisure types in the relationship between childhood trauma and psychological distress was examined. Results: Totally 19.1% of the upper elemetary school students exhibited psychological distress, while 30.2% had experienced childhood trauma. During school days, 64.6% of the students were reported of having leisure time concentrated between 1 and 5 hours per day, whereas 67.4% reported leisure time exceeding 5 hours per day on weekends. After controlling for potential demographic confounders such as gender, grade, ethnicity, household registration, being an only child, parents educational level, co residence, and whether parents are first time married,linear regression analysis showed that childhood trauma experience had positive predictive effect on psychological distress in upper primary school students( β =0.20, P <0.01). Leisure time showed no statistically significant association with psychological distress, both on school days ( β =-0.58 to -0.56) and weekends ( β =0.26- 0.98 )(all P >0.05). Active leisure activities were negatively associated with psychological distress ( β =-0.20), while passive leisure activities were positively associated with psychological distress ( β =0.29)(both P <0.01). Leisure type partially mediated the relationship between childhood trauma and psychological distress, accounting for 11.7% of the indirect effect. Conclusion Childhood trauma experiences positively predict psychological distress in upper elementary school students, and affect psychological distress through active leisure and passive leisure.

ObjectiveTo investigate the efficacy of sequential tenofovir alafenamide fumarate （TAF） therapy versus the regimen of entecavir （ETV） combined with TAF in chronic hepatitis B （CHB） patients experiencing low-level viremia （LLV） after ETV therapy， as well as their impact on virologic response， liver and renal function， and blood lipid levels. MethodsA total of 217 CHB patients with LLV after ETV treatment who were admitted to Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from May 2020 to December 2023 were enrolled， and according to the treatment regimen， they were divided into TAF group （180 patients receiving sequential TAF therapy） and combined group （37 patients receiving ETV+TAF therapy）. The propensity score matching （PSM） method was used to match the patients at a ratio of 1∶1， and finally 37 patients were included in each group to balance the baseline confounding factors. The two groups were compared in terms of hepatitis B virus DNA （HBV DNA） clearance rate， hepatitis B envelope antigen （HBeAg） clearance rate， liver and renal function parameters （liver stiffness measurement ［LSM］， platelet count ［PLT］， aspartate aminotransferase ［AST］， alanine aminotransferase ［ALT］， and creatinine ［Cr］）， blood lipid levels （total cholesterol ［TC］， triglyceride ［TG］， high-density lipoprotein cholesterol ［HDL-C］， and low-density lipoprotein cholesterol ［LDL-C］）， and the incidence rate of adverse reactions. The independent samples t-test was used for comparison of normally distributed continuous data between two groups， and the paired t-test was used for comparison within each group； the chi-square test was used for comparison of categorical data between groups. ResultsAfter 48 weeks of treatment， compared with the TAF group， the combined group had significantly higher HBV DNA clearance rate （86.49% vs 59.46%， χ²=6.852， P=0.009） and HBeAg clearance rate （59.46% vs 35.14%， χ²=4.391， P=0.036）. After treatment， compared with the TAF group， the combined group had significantly lower levels of LSM （7.01±1.50 kPa vs 7.90±1.68 kPa， t=2.404， P=0.019）， AST （18.02±2.28 U/L vs 21.12±2.85 U/L， t=5.166， P<0.001）， and ALT （19.85±3.86 U/L vs 22.00±3.90 U/L， t=2.383， P=0.020） and significantly higher levels of PLT ［（218.35±42.60）×10⁹/L vs （192.82±44.13）×10⁹/L， t=2.532， P=0.014］ and Cr （70.92±6.54 μmoL/L vs 67.60±6.13 μmoL/L， t=2.253， P=0.027）. After treatment， there was a slight increase in the level of TC in both the TAF group （5.60±0.89 mmol/L vs 5.18±0.85 mmol/L， t=2.076， P=0.041） and the combined group （5.45±0.80 mmol/L vs 5.02±0.83 mmol/L， t=2.269， P=0.026）. There was no significant difference in the incidence rate of adverse reactions between the TAF group and the combined group （21.62% vs 18.92%， χ²=0.084， P=0.772）. ConclusionFor ETV-treated CHB patients experiencing LLV， compared with sequential TAF therapy， the ETV+TAF combined therapy can effectively increase virologic response rate， alleviate liver fibrosis， and improve liver function， whereas sequential TAF therapy has less impact on renal function. Sequential or combined therapy with TAF may induce a slight increase in the level of TC， which should be taken seriously in clinical practice.

ObjectiveTo investigate the status of overlapping hepatitis B virus （HBV） infection in patients with chronic hepatitis C virus （HCV） infection and the serological characteristics of such patients. MethodsA total of 8 637 patients with HCV infection who were hospitalized from January 1， 2010 to December 31， 2020 and had complete data of HBV serological markers were enrolled， and the composition ratio of patients with overlapping HBV serological markers was analyzed among the patients with HCV infection. The patients were divided into groups based on age and year of birth， and serological characteristics were analyzed， and the distribution of HBV-related serological characteristics were analyzed across different HCV genotypes. ResultsThe patients with HCV/HBV overlapping infection accounted for 5.85%， and the patients with previous HBV infection accounted for 48.10%； the patients with protective immunity against HBV accounted for 14.67%， while the patients with a lack of protective immunity against HBV accounted for 31.39%. The patients were divided into groups based on age： in the 0 — 17 years group， the patients with protective immunity against HBV accounted for 61.41% （304 patients）； the 18 — 44 years group was mainly composed of patients with previous HBV infection （698 patients， 37.31%）， the 45 — 59 years group was predominantly composed of patients with previous HBV infection （1 945 patients， 50.38%）， and the ≥60 years group was also predominantly composed of patients with previous HBV infection （1 486 patients， 61.66%）. The patients were divided into groups based on the year of birth： in the pre-1992 group， the patients with previous HBV infection accounted for 51.63% （4 112 patients）； in the 1992 — 2005 group， the patients with protective immunity against HBV accounted for 54.72% （168 patients）； in the post-2005 group， the patients with protective immunity against HBV accounted for 64.38% （235 patients）. In this study， 6 301 patients underwent HCV genotype testing： the patients with genotype 1b accounted for the highest proportion of 51.71% （3 258 patients）， followed by those with genotype 2a （1 769 patients， 28.07%）， genotype 3b （63 patients， 1.00%）， genotype 3a （10 patients， 0.16%）， genotype 4 （21 patients， 0.33%）， and genotype 6a （5 patients， 0.08%）. ConclusionWith the implementation of hepatitis B planned vaccination program in China， there has been a significant reduction in the proportion of patients with previous HBV infection among the patients with HCV/HBV overlapping infection， but there is still a relatively high proportion of patients with a lack of protective immunity against HBV.