De-Zhong Xu

Mother-to-infant transmission of hepatitis B virus: a Chinese experience.

Over 90% of infants infected with hepatitis B virus (HBV) caused by mother‐to‐infant transmission will evolve to carrier status, and this cannot be prevented until widespread administration of the HB vaccine and hepatitis B immune globulin (HBIG) is implemented. This prospective study of 214 infants born to HBsAg‐positive mothers was carried out to determine if either perinatal or intrauterine HBV transmission could be effectively prevented with HBIG and the HB vaccine. Peripheral blood was collected from mothers and from newborns before they received HBIG and the HB vaccine, as well as at 0, 1, 7, 24, and 36 months after birth. Infants born with an ratio of signal to noise(S/N) value of >5 for HBsAg (ABBOTT Diagnostic Kit) were defined as mother‐to‐infant transmission cases, those with an S/N between 5 and 50 were classified as perinatal transmission cases, and those with an S/N >50 were considered intrauterine transmission cases. Mother‐to‐infant transmission occurred in approximately 4.7% (10/214) of the infants; the perinatal transmission and intrauterine transmission rates were 3.7% (8/214) and 0.9% (2/214), respectively. The risk of mother‐to‐infant transmission increased along with maternal HBeAg or HBVDNA levels. After 36 months of follow‐up, all perinatal cases became HBsAg‐negative, whereas all intrauterine transmission cases evolved into carrier status. These results indicate that infants infected via intrauterine transmission cannot be effectively protected by HBIG and HB vaccine. J. Med. Virol. 83:791–795, 2011.

Occult Hepatitis B Virus Infection in Anti-HBs-Positive Infants Born to HBsAg-Positive Mothers in China

Objective To investigate the prevalence of occult HBV infection (OBI) among children and to characterize virology of occult HBV, we conducted an epidemiological survey. Methods 186 HB-vaccinated infants born to HBsAg-positive mothers were included in the study. Serological tests for HBV markers were performed using commercial ELISA kits. Real-time quantitative PCR and nested PCR were used to detect HBV DNA. PCR products of the C and pre-S/S regions were sequenced and analyzed. Results 1.61% (3/186) infants were HBsAg positive, and 4.92% (9/183) infants were considered as occult infection. The viral load of mothers was associated with occult infection (P = 0.020). Incomplete three-dose injections of HB vaccine was associated with HBV infection (P = 0.022). Six OBI infants were positive for anti-HBs, but their titers were not greater than 100 mIU/mL. Seven isolated HBV pre-S/S sequences were obtained from nine OBI infants. Three of the sequences were genotype C, and four of the sequences were genotype C/D. Escape mutation S143L was found in the four sequences of genotype C/D. All seven sequences lacked G145R and other escape mutation in S region. Conclusions Occult HBV infection was detected in anti-HBs positive infants born to HBsAg-positive mothers in China. Occult infection was associated with absent anti-HBs or with low anti-HBs level, high maternal viral loads and escape mutations in the S gene.

Association between genomic heterogeneity of hepatitis B virus and intrauterine infection.

Hepatitis B virus (HBV) intrauterine infection remains to be an important cause for a large number of persistent hepatitis B surface antigen (HBsAg) positive carriers in areas with a high HBV prevalence, particularly in China and Southeast Asia. In this study, the possible association between the HBV genomic heterogeneity and intrauterine infection was investigated by comparing the quasi species isolated from eight pairs of HBsAg-positive mothers and their neonates, who were infected intrauterinely with HBV, with clones from eight HBsAg-positive mothers whose neonates were not infected with HBV. The proportion of clones with specific mutations was compared among different subject groups, and phylogenetic analysis was performed to evaluate the significance of specific mutations. It was observed that the core promoter with conserved major functional regions and conserved hepatitis B e antigen (HBeAg) might be beneficial to HBV maternal-fetal transmission. Particularly, A1762T/G1764A mutations seemed to be disadvantageous for fetal infection. It was also shown that amino acid substitutions located in the immune epitopes of HBsAg were strongly associated with intrauterine HBV transmission. The clones with mutations such as amino acid P110S in preS1 region, P36L in preS2 region and C107R in S region might infect fetuses more readily. In addition, positively selected site analysis confirmed the above results.

Maternal hepatitis B virus (HBV) DNA positivity and sexual intercourse are associated with HBV intrauterine transmission in China: A prospective case–control study

Background and Aim:  Hepatitis B virus (HBV) intrauterine transmission from infected mothers contributes significantly to the persistence of the high number of HBV carriers. The aim of this study was to identify potential risk factors for HBV intrauterine transmission.

Establishment and characterization of a spontaneously immortalized trophoblast cell line (HPT-8) and its hepatitis B virus-expressing clone

BACKGROUND Most trophoblast cell lines currently available to study vertical transmission of hepatitis B virus (HBV) are immortalized by viral transformation. Our goal was to establish and characterize a spontaneously immortalized human first-trimester trophoblast cell line and its HBV-expressing clone. METHODS Chorionic villi of Asian human first-trimester placentae were digested with trypsin and collagenase I to obtain the primary trophoblast cell culture. A spontaneously immortalized trophoblast cell line (HPT-8) was analyzed by scanning and transmission electron microscopy, cell cycle analysis, immunohistochemistry and immunofluorescence. HPT-8 cells were stably transfected with the adr subtype of HBV (HPT-8-HBV) and characterized by PCR and enzyme-linked immunosorbent assay. RESULTS We obtained a clonal derivative of a spontaneously immortalized primary cell clone (HPT-8). HPT-8 cells were epithelioid and polygonal, and formed multinucleate, giant cells. They exhibited microvilli, distinct desmosomes between adjacent cells, abundant endoplasm, lipid inclusions and glycogen granules, which are all characteristic of cytotrophoblasts. HPT-8 cells expressed cytokeratin 7, cytokeratin 18, vimentin, cluster of differentiation antigen 9, epidermal growth factor receptor, stromal cell-derived factor 1 and placental alkaline phosphatase. They secreted prolactin, estradiol, progesterone and hCG, and were positive for HLA-G, a marker of extravillous trophoblasts. HPT-8-HBV cells were positive for HBV relaxed-circular, covalently closed circular DNA and pre-S sequence. HPT-8-HBV cells also produced and secreted HBV surface antigen and HBV e antigen. CONCLUSIONS We established a trophoblast cell line, HPT-8 and its HBV-expressing clone which could be valuable in exploring the mechanism of HBV viral integration in human trophoblasts during intrauterine infection.

High conservation of hepatitis B virus surface genes during maternal vertical transmission despite active and passive vaccination.

Objective: Our purpose was to explore the relationship between hepatitis B virus (HBV) gene heterogeneity and maternal vertical transmission. Methods: HBsAg-positive mothers and their neonates were selected and classified into a vertical infection neonate group (group N), a vertical infection mother group (group M) and a control group (group C). Serum HBsAg and HBeAg were examined. HBV gene fragments, including the pre-S1, and pre-S2 and S coding regions, were amplified and sequenced, and the genotype and serotype of the sequences were identified. Mutation sites and frequency of mutations were then compared between group N and group C. Results: A total of 104 HBV clone sequences were obtained. All obtained sequences belonged to genotype C and serotype adr. Upon comparing sequences between group N and group C, 4 nonsynonymous mutations were found with significant difference in mutation frequency (p < 0.05). When the mothers were both HBsAg and HBeAg positive, 10 nonsynonymous mutations were found. The frequencies of these mutations were significantly lower in group N than in group C (p < 0.05). Conclusion: The 10 HBV mutations were negatively associated with vertical transmission when maternal HBeAg was positive. Furthermore, the species that were vertically transmitted to the fetus were mainly wild-type.

A preliminary study on the molecular evolution of the two routes of intrauterine transmission of HBV

Intrauterine transmission of hepatitis B virus (HBV) is one of the main reasons for the failure of vaccination and plays an important role in areas with high HBV prevalence. In the present study, the quasispecies isolated from eight pairs of HBsAg-positive mothers and their neonates, who were infected with HBV by intrauterine transmission, were selected as study subjects. Phylogenetic trees of the HBV strains of each pair of mother and neonate were constructed, the topological structures were compared, and the distance between and within the quasispecies was calculated. The eight phylogenetic trees included four types. In the first type, the maternal and neonatal sequences clustered into one clade. In the second type, the sequences of the mothers and neonates formed separate monophyletic clusters, and the two clades were sister groups. In the third type, the strains of mother were the ancestors of the neonatal strains. In the fourth type, the strains of the mothers clustered with only some of the sequences of the neonate, and the other strains of the neonate formed another monophyletic group. Combined with the genetic distance, possible transmission routes of the eight cases are proposed.

Screening Cellular Proteins Binding to the Core Region of Hepatitis C Virus RNA Genome with Digoxin-Labeled Nucleic Acids

Objective: To screen and identify cellular proteins binding to the core region of hepatitis C virus (HCV) RNA genome. Methods: The plasmid pHCV core was constructed to generate in vitro transcripts of the core region of HCV RNA genome. Ultraviolet (UV) cross-linking experiment and competition analysis were performed to screen HepG2 cellular proteins, which interact with digoxin-labeled transcripts of the core region of HCV RNA genome. RNA-binding proteins were separated by immunoprecipitation, analyzed by electrophoresis on SDS-PAGE and detected by immunoblotting with anti-digoxingenin-AP. After being excised from SDS-PAGE, the proteins bands were analyzed by MALDI-TOF-MS. Results: Several cellular proteins of hepG2 cell specifically bound to the core region of HCV RNA genome. The binding of cellular proteins to digoxin-labeled HCV core RNA was competed out in proportion to the increasing amount of unlabeled RNA. One of the HCV RNA-binding proteins was the B (brain) isozyme of human phosphoglycerate mutase (PGAM-B) identified by MALDI-TOF-MS. Conclusion: PGAM-B could specifically bind to the core region of HCV RNA genome in vitro.

Unique Epidemiological Patterns and Origin of the Outbreak of Human Infection with H7N9 AIV in China from 2013 to 2015

Background: Novel Human Avian Influenza (H7N9) (h-H7N9 AI) occurred in China in February, 2013 and continued today. Although there were many reports on epidemiology, the reservoir and origin have not been confirmed. Methods: Until April 2015, 628 cases collected from WHO. Descriptive epidemiology was used to compare differences between h-H7N9 AI and other h-AI with statistical analysis. Results: Compared with only 18 cases of h-H5N1 AI located just in Hong Kong during 7 months, 571 cases with 212 died (37%) occurred up to February, 2015 and only limited in the mainland. It is suggested h-H7N9 AI were fully different from other h-AI, and may belong to very new type of “Natural Focus Disease (Zoonosis)”. H7N9 AIV was not detected in farms and wild birds in China before and during the early phase, and quite different from h-H5N1 AI occurred in geese of Guangdong in 1996 and in farms in 1997. So, h-H7N9 AI should have occurred in countries with it in birds and poultry for long time, rather than in China. The mean age was 62 years old in the beginning, then decreased to 59.0, 58.0 and 2 years later to 54.8, with correlation of the epidemic-lasting days (r=-0.953P=0.047). It indicated that the senior had no specific immunity and H7N9 AIV was absolutely new virus and never existed in China. Interpretation: We have creatively identified that h-H7N9 AI is with unique pattern based on abnormities in incidence and distributions and should has occurred in another country with it for long time.

Hepatitis B virus infection status in the peripheral blood mononuclear cells of newborns of hepatitis B surface antigen positive mothers

Hepatitis B virus infection status in the peripheral blood mononuclear cells of newborns of hepatitis B surface antigen positive mothers