Memory T cells specific for HBV enumerated by a peptide-based cultured enzyme-linked immunospot assay in healthy HBV-vaccinated subjects

Irene Cassaniti, Sandra A. Calarota, Kodjo M G Adzasehoun, Antonella Chiesa, Giuditta Comolli, Maurizio Parea, Fausto Baldanti

Research output: Contribution to journalArticlepeer-review


Hepatitis B vaccine is the most effective strategy to control hepatitis B virus (HBV) infection and disease. It is considered that an anti-HBs (antibodies against HBV surface antigen) titer >10 mIU/ml, measured shortly after a complete vaccination schedule, provides protection against infection. Approximately 4–10% of healthy individuals fail to respond to 3-dose vaccination. Long-term HBV-specific memory T-cell response has not been fully investigated, mainly due to the lack of a suitable assay. We quantified HBV-specific expandable memory T cells by using a cultured IFN-γ enzyme-linked immunospot (ELISPOT) assay. Cultured ELISPOT response to an overlapping peptide pool representing the complete L (large) HBV envelope polypeptide was evaluated in 41 healthy subjects vaccinated 15–20 y earlier and 5 unvaccinated. Plasma samples were tested for anti-HBs. Vaccinated subjects had significantly higher HBV-specific T-cellular response than unvaccinated (p = 0.0002). HBV-specific T-cell response was mainly mediated by CD4+ T cells. No concordance was found between cultured ELISPOT and anti-HBs data in vaccinated subjects. Thirty-one (76%) vaccinated subjects were responders (anti-HBs >10 mIU/ml). Nineteen (46%) vaccinated subjects were considered to be responders in cultured ELISPOT. Twenty-two (54%) vaccinated subjects were considered non-responders in cultured ELISPOT; 5 of them (23%) were also humoral non-responders. About 12% of healthy HBV-vaccinated subjects are both humoral and cellular non-responders. Although the prognostic value of this assay has not been established in terms of predictability for susceptibility to de-novo HBV infection, ELISPOT data suggest that these subjects may be at risk for HBV infection and disease, especially health care workers.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalHuman Vaccines and Immunotherapeutics
Publication statusPublished - Jul 29 2016


  • anti-HBsAg specific antibodies
  • cultured ELISPOT
  • hepatitis B vaccine
  • hepatitis B virus
  • memory T cells

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Pharmacology


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