title: [HBsAg uptake into human trophoblasts cultured in vitro].
abstract: OBJECTIVE
  To detect the entry of HBsAg into human trophoblasts cultured in vitro, to provide some clues for the mechanism responsible for HBV intrauterine transmission.
  
  
  METHODS
  Digestion with both trypsin (0.25%) and Dnase I(0.15 U/ml) followed by repeated purification was performed to obtain a homogeneous population of trophoblast cells. The well-developed cells during longitudinal phase were randomly divided in 6 groups, which were co-incubated respectively with HBsAg-anti-HBs complex (I), co-culture of heat-inactivated sera positive for HBsAg, HBeAg, and anti-HBc and sera with high titer anti-HBs(II), heat-inactivated sera positive for HBsAg, HBeAg, and anti-HBc(III), HBsAg (IV), heat-inactivated normal sera (V), and normal medium(VI). The coverglasses mounted with confluent cells were harvested for anti-HBs immunohistochemical staining.
  
  
  RESULTS
  The isolated cells comprised a highly purified villous trophoblast population and could meet the demands of further experiments. After co-incubation of the cells with different agents, HBsAg test yielded positive results in the cells co-incubated with the HBsAg-anti-HBs complex and in the co-cultures of heat-inactivated sera positive for HBsAg, HBeAg and anti-HBc with sera containing high-titer anti-HBs. HBsAg test was negative in all other cell groups.
  
  
  CONCLUSIONS
  Human trophoblast cells could take in HBsAg in the form of HBsAg-anti-HBs complex instead of single HBsAg molecule.
authors.affiliation: Department of Epidemiology, Fourth Military Medical University, Xi'an 710033, China.
authors.forename: Xue-ping
authors.initials: XP
authors.lastname: Wang
authors.forename: De-zhong
authors.initials: DZ
authors.lastname: Xu
authors.forename: Yuan-gui
authors.initials: YG
authors.lastname: Li
authors.forename: Yong-ping
authors.initials: YP
authors.lastname: Yan
authors.forename: Ke
authors.initials: K
authors.lastname: Men
authors.forename: Jing-xia
authors.initials: JX
authors.lastname: Zhang
mesh_terms: D000936:Antigen-Antibody Complex / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D006510:Hepatitis B Antibodies / Q000378:metabolism; D006514:Hepatitis B Surface Antigens / Q000378:metabolism*; D006801:Humans; D017452:Receptors, IgG / Q000032:analysis; D014327:Trophoblasts / Q000378:metabolism* / Q000821:virology
chemical_list: D000936:Antigen-Antibody Complex; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017452:Receptors, IgG