title: Long-term persistence of T cell memory to HBsAg after hepatitis B vaccination.
abstract: OBJECTIVE
  To determine if the T cell memory to HBsAg can persist for a long time after hepatitis B (HB) vaccination.
  
  
  METHODS
  Thirty one vaccine recipients who were healthcare workers (18 females and 13 males aged 34-58 years) from Utrecht University Hospital, Netherlands, and had previously received a standard course of vaccination for hepatitis B were investigated and another 9 unvaccinated healthy volunteers from the same hospital were used as the control. Blood samples were taken just before the experiment to test serum anti-HBs levels and the subjects were classified into different groups according to their serum titers of anti-HBs and vaccination history. Their peripheral blood mononuclear cells (PBMC) were isolated from freshly heparinized venous blood and the proliferative response of T lymphocytes to the recombinant hepatitis B surface antigen (HBsAg) was investigated.
  
  
  RESULTS
  Positive serum anti-HBs was found in 61.3% (19/31) vaccine recipients and a significant in vitro lymphocyte proliferative response to recombinant HBsAg was observed in all the vaccinees with positive anti-HBs. Serum anti-HBs level < or =10 IU/L was found in 38.7% (12/31) subjects. In this study, we specially focused on lymphocyte proliferative response to recombinant HBsAg in those vaccine recipients with serum anti-HBsAg less than 10 IU/L. Most of them had received a standard course of vaccination about 10 years before. T lymphocyte proliferative response was found positive in 7 of the 12 vaccine recipients. These results confirmed that HBsAg-specific memory T cells remained detectable in the circulation for a long time after vaccination, even when serum anti-HBs level had been undetectable.
  
  
  CONCLUSIONS
  The T cell memory to HBsAg can persist for at least 10 years after HB vaccination. Further booster injection is not necessary in healthy responders to HB vaccine.
authors.affiliation: Shenyang Center for Disease Control and Prevention, Shenyang 110031, Liaoning Province, China. rxwtxh@pub.sy.ln.cn
authors.forename: Ru-Xiang
authors.initials: RX
authors.lastname: Wang
authors.forename: Greet J
authors.initials: GJ
authors.lastname: Boland
authors.forename: Jan
authors.initials: J
authors.lastname: van Hattum
authors.forename: Gijsbert C
authors.initials: GC
authors.lastname: de Gast
mesh_terms: D000328:Adult; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D007156:Immunologic Memory / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology; D008297:Male; D008875:Middle Aged
chemical_list: D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines