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

Abstract

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.

Characterization of Varicella-Zoster (VZV) Specific T Cell Response in Healthy Subjects and Transplanted Patients by Using Enzyme Linked Immunospot (ELISpot) Assays

“…In each experiment, a final concentration of 0.25 μg/mL of each peptide was used. Human interferon-gamma (IFN-y) ELISpot kits (Diaclone, Cedex, France) and MultiScreen-IP membrane-bottomed 96-well plates (Merck Millipore, Darmstadt, Germany) were used for standard ELISpot assays and for cultured ELIspot assays according to the previous protocols, with some modifications [ 13 , 19 ].…”

Lower frequency of T stem cell memory (TSCM) cells in hepatitis B vaccine nonresponders

“…In addition, decreased frequency and function of monocyte-derived dendritic cells (moDCs) and subsequently attenuated memory T cell induction had been considered a probable reason for being nonresponder to HB vaccine [ 42 ]. However, the long-term memory T cell response has not been fully elucidated in this regard [ 43 ]. To the best of our knowledge, no similar studies could be found regarding the frequency of various memory T cell subsets, particularly T SCM cells after vaccination, and their comparison between responders and nonresponders of healthy recipients.…”

Longitudinal mapping of hepatitis B vaccine‐induced B‐cell linear epitopes in healthy individuals

“…Thus, the waning of these immune cells might result in disastrously subsiding of the seroprotection against HBV, leading to feeble and short‐durable HBV‐specific immunity. Previous studies have documented that the polymorphisms of Tfh‐related genes and HBV‐specific T cells response were associated with the responsiveness to HB vaccine 9,12 . Besides, the hypofunction of memory B cells and plasmablasts was found in nonresponders after vaccination.…”

“…Previous studies have documented that the polymorphisms of Tfhrelated genes and HBV-specific T cells response were associated with the responsiveness to HB vaccine. 9,12 Besides, the hypofunction of memory B cells and plasmablasts was found in nonresponders after vaccination. Therefore, evidence with comprehensively analyzing the dynamics of immune response is imperative, which may contribute to the discernment of determining factors for vaccine efficiency and taking precautions for nonresponders in advance.…”