title: Characterization of hepatitis B surface antigen (HBsAg) induced interleukin-2 secretion in chronic asymptomatic carriers of HBsAg.
abstract: Peripheral T lymphocytes from asymptomatic HBsAg carriers and hepatitis B (HB) immune (naturally acquired or vaccine induced) donors were induced into interleukin-2 (IL-2) secretion by plasma-derived HBsAg and the translational products of the S- and pre-S2+S gene of HB virus (HBV) in vitro. Biphasic time courses of IL-2 secretion were obtained for all donors tested. The first peak seemed to be mitogenically induced, as it was demonstrated in T cell cultures from asymptomatic HBsAg carrier, HB-immune donors as well as HB-susceptible controls and exhibited similar kinetics to that of the mitogen phytohaemagglutinin (PHA) induced IL-2 secretion. The mitogenically induced IL-2 secretion was prompt in T cell cultures from asymptomatic HBsAg carriers compared with HB-immune and HB-susceptible donors, and significantly higher after stimulation with high (100-1,000 ng/ml) compared with low (0.1-1.0 ng/ml) concentrations of HBsAg, indicating that T lymphocytes from asymptomatic HBsAg carriers are mitogenically pre-activated by circulatory HBsAg in high concentrations in vivo. In contrast, the second peak obtained after 4-7 days of antigen stimulation was antigen-specifically induced as it was not registered in control culture supernatants from HB-susceptible individuals. T cells from six out of seven asymptomatic HBsAg carriers exhibited reduced responsiveness to the translational product of the S-gene of HBV, whereas T cells from HB-immune donors responded equally well to pre-S2 containing and non-containing HBsAg preparations. An HBsAg-induced mitogenic T cell activation and aberrant T cell sensitization towards S-gene-encoded determinants may result in altered immunoregulatory functions within the T cell compartment, with consequences for the development of an adequate antibody response to HBsAg in asymptomatic HBsAg carriers.
authors.affiliation: Department of Infectious Diseases, Karolinska Institute, Roslagstull Hospital, Stockholm, Sweden.
authors.forename: S P
authors.initials: SP
authors.lastname: Sylvan
authors.forename: U B
authors.initials: UB
authors.lastname: Hekkström
mesh_terms: D000328:Adult; D002353:Carrier State; D005260:Female; D005814:Genes, Viral; D006509:Hepatitis B / Q000276:immunology*; D006514:Hepatitis B Surface Antigens / Q000008:administration & dosage* / Q000097:blood / Q000302:isolation & purification; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D006514:Hepatitis B Surface Antigens; D007376:Interleukin-2