Viral specific T cells phenotypes and toll like receptors mRNA expression in CD8 cells of chronic hepatitis B patients

Abstract

Background The clearance or persistence of hepatitis B virus(HBV) is affected by HBV-specific cytotoxic T-lymphocyte (CTL).Since toll like receptors (TLRs) may contribute to the viral specificT cells. But what and how the TLRs take their functions in chronichepatitis B (CHB) patients remains unknown.Aims To investigate the association of TLRs in CD8+ T cells andtheir relationship with CTL cells in chronic hepatitis B patients.Material and methods Peripheral blood mononuclear cells(PBMC) were collected from 28 HLA-A2+ patients. Group A (n =8) were patients with spontaneous resolution of CHB (anti-HBc plusanti-HBs positive) while Group B (n = 20) was HBeAg (+) CHBpatients. Ex-vivo model:The PBMC of these patients were co-culturedwith live hepatitis B virus (HBV) for 7 days. PBMC were stained forthe frequency of CD4, CD8, CD45RA, CD45RO and CCR7 byFACS analysis. Viral specific CD8 cells were tested by tetramer toHLA-A2 limited HBV peptides. CD8+ cells were isolated and TLRs-2, 3 4 and 7 mRNA level in CD8+ cells and HBV DNA were testedby real time PCR. Interferon-g secretion was tested by ELISpot.Results After co-culture, there was an increase in HBV-specificCD8+tetramer+ cells in Group A when compared with Group B(mean ± SD 1.971 ± 0.694% vs. 0.7 ± 0.362%, respectively, P 0.001).Interferon-γ secretion was higher in Group A when compared with ingroup B on day 7 after stimulation (SFC were 304.25 ± 156.12 inGroup A and 49.6 ± 46.04 in Group B, P = 0.0002).The HBV DNAin the ex-vivo model was lower in Group A from day-5 to Day-7 ofco-culture. The frequency of CD8+CD45RA-CCR7-cells before co-culture was similar in both groups In both groups, 90% of the HBV-specific CD8+ cells were CD45RA-CCR7- effecter-memory T cells.TLR2, 3 and 4 mRNA were higher expressed in Group A than inGroup B. But only TLR4 has statistic significance (mean ± SD 2.915± 1.536 in Group A vs. 1.010 ± 0.988 in Group B respectively, p0.006).Conclusion HBV-specific CD8+tetramer+ cells are higher inpatients with spontaneous resolution of chronic HBV. TLR4 may beassociated with activation T memory cell in response to HBV.There were no significant differences among the phenotypes ofCD8/tetramer positive cells between the two groups.