ObjectiveTo prepare a recombinant PETase with a dual-catalytic-triad and to evaluate its efficiency in the biodegradation of polyethylene terephthalate （PET）. MethodsBased on the crystal structure of wild-type PETase， point mutations （T88H/L117D） were introduced via site-directed mutagenesis. The recombinant protein was prepared using prokaryotic expression and chromatography purification techniques. The enzymatic hydrolysis of the mutant PETase was assessed by relatively quantifying the products mono （2-hydroxyethyl） terephthalate （MHET） and terephthalic acid （TPA）. ResultsBoth wild-type and mutant PETases accumulated as inclusion bodies， accounting for approximately 20% of the total bacterial protein. After solubilization in urea， the proteins were eluted at 300 mmol/L imidazole during affinity chromatography purification， with concentrations of 1.824 and 1.833 mg/mL and purities of 83.11% and 84.32%， respectively. Subsequent anion-exchange chromatography yielded highly pure enzymes in the 200 mmol/L NaCl fraction： 2.776 mg/mL （96.86% purity） for the wild type and 1.967 mg/mL （95.13% purity） for the mutant. Following refolding， the final concentrations were 0.484 mg/mL for the wild type and 0.991 mg/mL for the mutant. Hydrolysis assays revealed that the mutant released MHET and TPA at （237.67±17.00）% and （197.33±12.01）% of the wild-type levels， respectively. ConclusionThe T88H/L117D dual-catalytic-triad PETase is successfully prepared and it significantly enhanced PET-degrading activity， thus， it′s a promising biocatalyst for PET bioremediation.

Objective:To analyze the genetic characteristics and evolutionary origin of hepatitis B virus (HBV) subgenotype D3 in China in 2020.Methods:Serum samples and demographic details from patients infected with HBV D3 subgenotype were collected. HBV genomic sequences were obtained by nested PCR amplification and subsequent sequencing. Phylogenetic analysis, nucleotide homology, amino acid mutation and evolution rate of the S protein were conducted by comparing with reference sequence using bioinformatics tools.Results:The complete HBV gene sequences of 14 samples of D3 subtype HBV were obtained. Compared with 97 reference sequences, it was found that the sequences with the highest homology were from India, Mongolia, Iran and China, with the homology ranging from 96.0% to 97.9%. Mutations of 24 amino acids were found in 14 strains of D3 subtype. Among them, T131A, Y134F and T140I were associated with immune escape-related mutations. The genetic diversity of HBV D3 subtype increased slowly before 1975, remained relatively constant from 1975 to 2000, and began to decline after 2000. Evolutionary rate analysis showed that samples QGLD D3-02 and 03 originated from a common ancestor with the Iranian reference strain in 1872, and the other 12 samples QGLD D3-04-17 originated from a common ancestor with the Mongolian reference strain in 1843.Conclusions:The gene sequence of HBV D3 subtype in China had the highest homology with reference sequences from India, Iran, Mongolia and China. Evolutionary rate analysis revealed that 14 cases of HBV D3 subtype originated from a common ancestor with reference strains from Mongolia and Iran, which enriched the sequence and evolution information of HBV D3 subtype and provided a reference basis for the molecular epidemiological study of HBV.

Objective:To evaluate the long-term protective efficacy of the recombinant Chinese hamster ovary cell-derived hepatitis B vaccine（CHO-HepB）26 years post-vaccination in the rural China.Methods:Zhengding county，Hebei province was designated as a rural monitoring site for CHO-HepB efficacy. Study participants included individuals born between 1997 and 1999 who had completed the three-dose CHO-HepB primary series without booster doses. A cross-sectional survey was conducted in late 2024 using random sampling. Demographic and vaccination history data were collected via questionnaires，and hepatitis B virus（HBV）serological markers were detected using chemiluminescence. Historical surveillance data were integrated to infer infection statuses of HBsAg-positive individuals and evaluate longitudinal trends in anti-HBs seropositivity and antibody titers.Results:Among 178 participants（mean time since vaccination：26.2 years），the seroprevalence rates were 0.6% for HBsAg（95% CI：0.0%-1.6%），64.6% for anti-HBs（95% CI：57.6%-71.6%），and 1.1% for anti-HBc（95% CI：0.0%-2.7%）. Compared to the pre-vaccination baseline HBsAg positivity of 11.3% in children under 10 years of age，the estimated vaccine protection rate was 95%. Two notable cases were identified：one with concurrent HBsAg and anti-HBc positivity and one with anti-HBs and anti-HBc positivity，suggestive of transient HBV exposure（1999—2009）without chronicity. Natural immune boosting was inferred for the latter case based on anti-HBs titer dynamics. Longitudinal analysis of four prior cross-sectional surveys（2005，2009，2013，and 2017）revealed no significant upward trends in HBsAg and anti-HBc positivity（both P>0.05）over 26 years，while anti-HBs seropositivity declined significantly（ P<0.05）from 6 to 26 years post-vaccination. Conclusion:The CHO-HepB vaccine demonstrates sustained immunological persistence and robust long-term protection up to 26 years post-immunization. Continued emphasis on rigorous implementation of mother-to-child transmission prevention strategies is critical for future hepatitis B control.

Hepatitis B，an infectious disease caused by the hepatitis B virus（HBV），poses a severe threat to health by inducing acute and chronic hepatitis，cirrhosis，and liver cancer，thereby imposing heavy disease burden and psychological pressure to patients. In 1992，the average positive rate of hepatitis B surface antigen（HBsAg）in China was 9.75%，classifying the country as a high-prevalence area for hepatitis B. Since the mid-1980s，China has implemented a comprehensive prevention and control strategy centered on hepatitis B vaccination for newborns. This strategy encompasses measures such as blocking mother-to-child transmission，blood screening，control of healthcare-associated infections，prevention and control among key populations，and public education and awareness campaigns. After nearly four decades of efforts，the 2020 national hepatitis B seroepidemiological survey revealed a significant decline in China's overall HBsAg positive rate to 5.86%，with the positivity rate among children aged 1-4 years plummeting to just 0.30%. Compared with 1992，they have decreased by 40% and 97% respectively. New HBV infections have significantly decreased，and the prevention and control measures have achieved remarkable economic and social benefits. However，China still confronts numerous challenges in eliminating hepatitis B. The number of chronic HBV carriers remains substantial，and the infection rates among childbearing-age populations and sexually active groups are still relatively high. New infections among adults continue to occur sporadically. Additionally，the vaccination rate for hepatitis B among high-risk adult populations is low，and the newborn immunization program is weak in some areas. The public's awareness of hepatitis B needs to be improved urgently. The rates of detection，diagnosis，and treatment for hepatitis B are relatively low. Moreover，there is currently no effective drug that can completely eliminate HBV. Against the backdrop of rapid advancements in internet and information technologies，as well as in detection and diagnostic methods，China should promptly develop a multi-department prevention and control plan，introduce supportive policies and safeguard measures，and implement a hepatitis B prevention and control strategy that is based on universal immunoprevention and is systematic，comprehensive，standardized，precise，and fully integrated. At the same time，it is essential to improve an information management system，explore the integration of medical care and disease prevention mechanisms，increase financial investment，and implement measures at all stages，including screening，diagnosis，referral，treatment，and care. Additionally，efforts should be made to mobilize the participation of the entire society in order to achieve the goal of eliminating the public health threat of hepatitis B as soon as possible.

Objective:To investigate the distribution and epidemiological patterns of hepatitis B virus（HBV）serological markers among pediatric surgical inpatients in Beijing.Methods:A retrospective cross-sectional study was conducted using data from all surgical inpatients（0?18 years of age）at a tertiary children’s hospital in Beijing between January 2019 and December 2024. Five HBV serological markers（HBsAg，anti-HBs，anti-HBc，HBeAg，anti-HBe）were analyzed and compared across sex，age，and ethnicity.Results:Of 15 339 children included，56.50% were male and 43.50% female；the 6?12-year age group predominated（37.41%），and Han ethnicity accounted for 91.61%. The overall positive rates were 0.78% for HBsAg，75.32% for anti-HBs，7.42% for anti-HBc，0.02% for HBeAg，and 3.05% for anti-HBe. The prevalences of “big three-positive”（HBsAg+/HBeAg+/anti-HBc+）and “small three-positive”（HBsAg+/anti-HBe+/anti-HBc+）patterns were only 0.02% and 0.04%，respectively. Boys had significantly higher anti-HBs（76.02% vs 74.40%）and anti-HBc（8.01% vs 6.69%）positivity than girls. HBsAg peaked in the 1?3-year group（1.75%）and was lowest in the 6?12-year group（0.19%）. Anti-HBs reached its highest level in the 3?6-year group（81.25%）and declined to 56.07% in adolescents（12?18 years）. No ethnic differences were observed.Conclusion:Universal HBV vaccination has achieved remarkable success among surgical inpatients in Beijing，as evidenced by high anti-HBs levels and very low rates of active or chronic infection. However，antibody titers wane with age，underscoring the need for targeted booster strategies for school-aged children.

Objective:To investigate the distribution and epidemiological patterns of hepatitis B virus（HBV）serological markers among pediatric surgical inpatients in Beijing.Methods:A retrospective cross-sectional study was conducted using data from all surgical inpatients（0?18 years of age）at a tertiary children’s hospital in Beijing between January 2019 and December 2024. Five HBV serological markers（HBsAg，anti-HBs，anti-HBc，HBeAg，anti-HBe）were analyzed and compared across sex，age，and ethnicity.Results:Of 15 339 children included，56.50% were male and 43.50% female；the 6?12-year age group predominated（37.41%），and Han ethnicity accounted for 91.61%. The overall positive rates were 0.78% for HBsAg，75.32% for anti-HBs，7.42% for anti-HBc，0.02% for HBeAg，and 3.05% for anti-HBe. The prevalences of “big three-positive”（HBsAg+/HBeAg+/anti-HBc+）and “small three-positive”（HBsAg+/anti-HBe+/anti-HBc+）patterns were only 0.02% and 0.04%，respectively. Boys had significantly higher anti-HBs（76.02% vs 74.40%）and anti-HBc（8.01% vs 6.69%）positivity than girls. HBsAg peaked in the 1?3-year group（1.75%）and was lowest in the 6?12-year group（0.19%）. Anti-HBs reached its highest level in the 3?6-year group（81.25%）and declined to 56.07% in adolescents（12?18 years）. No ethnic differences were observed.Conclusion:Universal HBV vaccination has achieved remarkable success among surgical inpatients in Beijing，as evidenced by high anti-HBs levels and very low rates of active or chronic infection. However，antibody titers wane with age，underscoring the need for targeted booster strategies for school-aged children.

Objective:To analyze the genetic characteristics and evolutionary origin of hepatitis B virus (HBV) subgenotype D3 in China in 2020.Methods:Serum samples and demographic details from patients infected with HBV D3 subgenotype were collected. HBV genomic sequences were obtained by nested PCR amplification and subsequent sequencing. Phylogenetic analysis, nucleotide homology, amino acid mutation and evolution rate of the S protein were conducted by comparing with reference sequence using bioinformatics tools.Results:The complete HBV gene sequences of 14 samples of D3 subtype HBV were obtained. Compared with 97 reference sequences, it was found that the sequences with the highest homology were from India, Mongolia, Iran and China, with the homology ranging from 96.0% to 97.9%. Mutations of 24 amino acids were found in 14 strains of D3 subtype. Among them, T131A, Y134F and T140I were associated with immune escape-related mutations. The genetic diversity of HBV D3 subtype increased slowly before 1975, remained relatively constant from 1975 to 2000, and began to decline after 2000. Evolutionary rate analysis showed that samples QGLD D3-02 and 03 originated from a common ancestor with the Iranian reference strain in 1872, and the other 12 samples QGLD D3-04-17 originated from a common ancestor with the Mongolian reference strain in 1843.Conclusions:The gene sequence of HBV D3 subtype in China had the highest homology with reference sequences from India, Iran, Mongolia and China. Evolutionary rate analysis revealed that 14 cases of HBV D3 subtype originated from a common ancestor with reference strains from Mongolia and Iran, which enriched the sequence and evolution information of HBV D3 subtype and provided a reference basis for the molecular epidemiological study of HBV.

Objective:To evaluate the long-term protective efficacy of the recombinant Chinese hamster ovary cell-derived hepatitis B vaccine（CHO-HepB）26 years post-vaccination in the rural China.Methods:Zhengding county，Hebei province was designated as a rural monitoring site for CHO-HepB efficacy. Study participants included individuals born between 1997 and 1999 who had completed the three-dose CHO-HepB primary series without booster doses. A cross-sectional survey was conducted in late 2024 using random sampling. Demographic and vaccination history data were collected via questionnaires，and hepatitis B virus（HBV）serological markers were detected using chemiluminescence. Historical surveillance data were integrated to infer infection statuses of HBsAg-positive individuals and evaluate longitudinal trends in anti-HBs seropositivity and antibody titers.Results:Among 178 participants（mean time since vaccination：26.2 years），the seroprevalence rates were 0.6% for HBsAg（95% CI：0.0%-1.6%），64.6% for anti-HBs（95% CI：57.6%-71.6%），and 1.1% for anti-HBc（95% CI：0.0%-2.7%）. Compared to the pre-vaccination baseline HBsAg positivity of 11.3% in children under 10 years of age，the estimated vaccine protection rate was 95%. Two notable cases were identified：one with concurrent HBsAg and anti-HBc positivity and one with anti-HBs and anti-HBc positivity，suggestive of transient HBV exposure（1999—2009）without chronicity. Natural immune boosting was inferred for the latter case based on anti-HBs titer dynamics. Longitudinal analysis of four prior cross-sectional surveys（2005，2009，2013，and 2017）revealed no significant upward trends in HBsAg and anti-HBc positivity（both P>0.05）over 26 years，while anti-HBs seropositivity declined significantly（ P<0.05）from 6 to 26 years post-vaccination. Conclusion:The CHO-HepB vaccine demonstrates sustained immunological persistence and robust long-term protection up to 26 years post-immunization. Continued emphasis on rigorous implementation of mother-to-child transmission prevention strategies is critical for future hepatitis B control.

Hepatitis B，an infectious disease caused by the hepatitis B virus（HBV），poses a severe threat to health by inducing acute and chronic hepatitis，cirrhosis，and liver cancer，thereby imposing heavy disease burden and psychological pressure to patients. In 1992，the average positive rate of hepatitis B surface antigen（HBsAg）in China was 9.75%，classifying the country as a high-prevalence area for hepatitis B. Since the mid-1980s，China has implemented a comprehensive prevention and control strategy centered on hepatitis B vaccination for newborns. This strategy encompasses measures such as blocking mother-to-child transmission，blood screening，control of healthcare-associated infections，prevention and control among key populations，and public education and awareness campaigns. After nearly four decades of efforts，the 2020 national hepatitis B seroepidemiological survey revealed a significant decline in China's overall HBsAg positive rate to 5.86%，with the positivity rate among children aged 1-4 years plummeting to just 0.30%. Compared with 1992，they have decreased by 40% and 97% respectively. New HBV infections have significantly decreased，and the prevention and control measures have achieved remarkable economic and social benefits. However，China still confronts numerous challenges in eliminating hepatitis B. The number of chronic HBV carriers remains substantial，and the infection rates among childbearing-age populations and sexually active groups are still relatively high. New infections among adults continue to occur sporadically. Additionally，the vaccination rate for hepatitis B among high-risk adult populations is low，and the newborn immunization program is weak in some areas. The public's awareness of hepatitis B needs to be improved urgently. The rates of detection，diagnosis，and treatment for hepatitis B are relatively low. Moreover，there is currently no effective drug that can completely eliminate HBV. Against the backdrop of rapid advancements in internet and information technologies，as well as in detection and diagnostic methods，China should promptly develop a multi-department prevention and control plan，introduce supportive policies and safeguard measures，and implement a hepatitis B prevention and control strategy that is based on universal immunoprevention and is systematic，comprehensive，standardized，precise，and fully integrated. At the same time，it is essential to improve an information management system，explore the integration of medical care and disease prevention mechanisms，increase financial investment，and implement measures at all stages，including screening，diagnosis，referral，treatment，and care. Additionally，efforts should be made to mobilize the participation of the entire society in order to achieve the goal of eliminating the public health threat of hepatitis B as soon as possible.

OBJECTIVE: The present study aimed to evaluate the immunogenicity of BA.2 variant receptor binding domain (RBD) recombinant protein formulated with CpG 1826 plus alum dual adjuvant. METHODS: The BA.2 variant RBD (residues 308-548) fusing TT-P ₂ epitope was obtained from prokaryotic expression system, purification technology and dialysis renaturation, which was designated as Sot protein. The soluble Sot protein formulated with CpG 1826 plus alum dual adjuvant was designated as Sot/CA subunit vaccine and then the BALB/c mice were intramuscularly administrated with two doses of the Sot/CA subunit vaccine at 14-day interval (day 0 and 14). On day 28, the number of effector T lymphocytes secreting IFN-γ and IL-4 in mice spleen were determined by enzyme-linked immunospot (ELISpot) assay. The serum IgG, IgG1 and IgG2a antibodies were examined by enzyme-linked immunosorbent assay (ELISA). In addition, the level of neutralizing antibodies (NAbs) induced by Sot/CA subunit vaccine was also evaluated by the microneutralization assay. RESULTS: The high-purity soluble Sot protein with antigenicity was successfully obtained by the prokaryotic expression, protein purification and dialysis renaturation. The Sot/CA subunit vaccine induced a high level of IgG antibodies and NAbs, which were of cross-neutralizing activity against SARS-CoV-2 BA.2 and XBB.1.5 variants. Meanwhile, Sot/CA subunit vaccine also induced a high level of effector T lymphocytes secreting IFN-γ (635.00 ± 17.62) and IL-4 (279.20 ± 13.10), respectively. Combined with a decreased IgG1/IgG2a ratio in the serum, which indicating Sot/CA subunit vaccine induced a Th1-type predominant immune response. CONCLUSION The Sot protein formulated with CpG 1826 plus alum dual adjuvant showed that the excellent cellular and humoral immunogenicity, which provided a scientific basis for the development of BA.2 variant subunit vaccines and references for the adjuvant application of subunit vaccines.
Animals ; COVID-19 Vaccines/immunology* ; Alum Compounds/pharmacology* ; Mice, Inbred BALB C ; Vaccines, Subunit/immunology* ; Mice ; SARS-CoV-2/immunology* ; Oligodeoxyribonucleotides/administration & dosage* ; Female ; Adjuvants, Immunologic ; COVID-19/immunology* ; Antibodies, Viral/blood* ; Immunogenicity, Vaccine ; Spike Glycoprotein, Coronavirus/immunology* ; Antibodies, Neutralizing/blood* ; Adjuvants, Vaccine ; Immunoglobulin G/blood*