ANALYSIS OF T CELL RECEPTOR Vβ DIVERSITY IN PERIPHERAL CD4+ AND CD8+ T LYMPHOCYTES OBTAINED FROM PATIENTS WITH CHRONIC SEVERE HEPATITIS B

摘要

Background: The hepatitis B virus (HBV) antigen-induced cellular immune response plays an important role in HBV clearance. Changes in the diversity of complementarity determining region 3 (CDR3) and T-cell receptor (TCR) sequences are used to monitor the response of T cells to antigens.Objectives: The aim of the present study was to determine whether the TCR V b repertoire of patients with chronic severe hepatitis B (CSHB) undergoes increased stimulation, and to identify conserved motifs in specific TCR V b families.Patients and Methods: Peripheral blood mononuclear cells (PBMCs) from 18 patients with CSHB were sorted into CD4+and CD8+T subsets, using monoclonal antibody-coated magnetic beads. The TCR V b CDR3 was subsequently characterized using immune spectratyping. The TCR V b families exhibiting a CDR3 spectratype that underwent monoclonal expansion were sequenced.Results: The number of oligoclonal or monoclonal expansion TCR V b families detected in the analyzed CD8+T cells was significantly higher than the number detected in CD4+T cells. The CDR3 spectratype analysis showed predominant usage of TCR V b 5, V b 7, V b 9, V b 12, and V b 18 families in CD8+T cell subsets of CSHB patients. Furthermore, conserved amino acid motifs were found to be associated with the monoclonal expansion of CD8+TCR V b families. In addition, JB1S1 and JB2S7 region genes were present at a high frequency.Conclusions: The CD4+and CD8+TCR V b gene families undergo clonal expansion in CSHB patients, and CD8+T cells play a major role in the pathogenesis of CSHB. Moreover, the conserved motifs and limited use of joining region genes observed in the CSHB patients of this cohort indicated that similar antigenic epitopes are recognized.