Analysis of T cell receptor variable regions and complementarity determining region 3 of infiltrating T lymphocytes in the liver of patients with chronic type B hepatitis

T-Cell Receptor β Chain and B-Cell Receptor Repertoires in Chronic Hepatitis B Patients with Coexisting HBsAg and Anti-HBs

Antibodies in response to antigens are related to the immune repertoire of T- and B-cell receptors. However, some patients with chronic hepatitis B (CHB) have coexisting HBsAg and anti-HBsAg antibodies (anti-HBs) that cannot neutralize HBV. We attempted to investigate the repertoires that produce this response in CHB patients. The T-cell receptor β chain (TRB) and B-cell receptor (BCR) repertoires of peripheral blood genomic DNA were analyzed using MiXCR. T-cell receptor (TCR) cluster analysis was carried out by clusTCR, and motifs prediction was selected by Multiple Em for Motif Elicitation (MEME). A total of 76 subjects were enrolled, including 26 HBsAg and anti-HBs coexisting patients with CHB (DP group), 25 anti-HBs single-positive healthy people (SP group), and 25 CHB patients (CHB group). The clone length of BCR in 39, 90 was significantly different among these groups (p = 0.005, 0.036). The motif “CASSLG” in the DP group was significantly higher than SP and CHB groups and may relate to coexistence, and the motif “GAGPLT” was only shown in the SP group and may relate to anti-HB expression. These provide important insights into vaccine development and CHB treatment.

T-Cell Receptor β Chain and B-Cell Receptor Repertoires in Chronic Hepatitis B Patients with Coexisting HBsAg and Anti-HBs

Antibodies in response to antigens are related to the immune repertoire of T- and B-cell receptors. However, some patients with chronic hepatitis B (CHB) have coexisting HBsAg and anti-HBsAg antibodies (anti-HBs) that cannot neutralize HBV. We attempted to investigate the repertoires that produce this response in CHB patients. The T-cell receptor β chain (TRB) and B-cell receptor (BCR) repertoires of peripheral blood genomic DNA were analyzed using MiXCR. T-cell receptor (TCR) cluster analysis was carried out by clusTCR, and motifs prediction was selected by Multiple Em for Motif Elicitation (MEME). A total of 76 subjects were enrolled, including 26 HBsAg and anti-HBs coexisting patients with CHB (DP group), 25 anti-HBs single-positive healthy people (SP group), and 25 CHB patients (CHB group). The clone length of BCR in 39, 90 was significantly different among these groups (p = 0.005, 0.036). The motif “CASSLG” in the DP group was significantly higher than SP and CHB groups and may relate to coexistence, and the motif “GAGPLT” was only shown in the SP group and may relate to anti-HB expression. These provide important insights into vaccine development and CHB treatment.

Analysis of the CDR3 length repertoire and the diversity of T cell receptor α and β chains in swine CD4+ and CD8+ T lymphocytes

The T cell receptor (TCR) is a complex heterodimer that recognizes fragments of antigens as peptides and binds to major histocompatibility complex molecules. The TCR α and β chains possess three hypervariable regions termed complementarity determining regions (CDR1, 2 and 3). CDR3 is responsible for recognizing processed antigen peptides. Immunoscope spectratyping is a simple technique for analyzing CDR3 polymorphisms and sequence length diversity, in order to investigate T cell function and the pattern of TCR utilization. The present study employed this technique to analyze CDR3 polymorphisms and the sequence length diversity of TCR α and β chains in porcine CD4⁺ and CD8⁺ T cells. Polymerase chain reaction products of 19 TCR α variable regions (AV) and 20 TCR β variable regions (BV) gene families obtained from the CD4⁺ and CD8⁺ T cells revealed a clear band following separation by 1.5% agarose gel electrophoresis, and each family exhibited >8 bands following separation by 6% sequencing gel electrophoresis. CDR3 spectratyping of all identified TCR AV and BV gene families in the sorted CD4⁺ and CD8⁺ T cells by GeneScan, demonstrated a standard Gaussian distribution with >8 peaks. CDR3 in CD4⁺ and CD8⁺ T cells demonstrated different expression patterns. The majority of CDR3 recombined in frame and the results revealed that there were 10 and 14 amino acid discrepancies between the longest and shortest CDR3 lengths in specific TCR AV and TCR BV gene families, respectively. The results demonstrated that CDR3 polymorphism and length diversity demonstrated different expression and utilization patterns in CD4⁺ and CD8⁺ T cells. These results may facilitate future research investigating the porcine TCR CDR3 gene repertoire as well as the functional complexity and specificity of the TCR molecule.

Profiling the repertoire of T-cell receptor beta-chain variable genes in peripheral blood lymphocytes from subjects who have recovered from acute hepatitis B virus infection

The profile of T-cell receptor beta-chain variable (TRBV) genes usually skews in subjects with virus infection or cancer. The gene melting spectral pattern (GMSP) can be used to determine the profile of the TRBV gene family. To explore the portrait of the TRBV family in peripheral blood lymphocytes from subjects who have recovered from acute hepatitis B virus infection (AHI), peripheral blood mononuclear cells (PBMCs) were separated and further sorted into CD4+ and CD8+ T-cell subsets. The molecular features of the TRBV complementary determining region 3 (CDR3) motifs were determined using GMSP analysis. When aGMSP profile showed a single peak, the monoclonally expanded TRBV gene was cloned and sequenced. Skewed expansions of multiple TRBV genes were observed among the CD4+ and CD8+ T-cell subsets and the PBMCs. The frequency of monoclonally expanded TRBV genes in the CD8+ T-cell subset was significantly higher than that of the CD4+ T-cell subset and the PBMCs. Compared to other members of the TRBV gene family, TRBV11, BV15 and BV20 were predominantly expressed in the repertoire of peripheral blood lymphocytes in recovered AHI subjects. The relatively conserved amino acid motifs of TRBV5.1 and BV20 CDR3 were also detected in the CD4+ and CD8+ T-cell subsets. These results demonstrate the presence of multiple biased TRBV families in recovered AHI subjects. TRBV11, BV15 and BV20, especially from the CD8+ T-cell subset, may be relevant to the pathogenesis of subjects with AHI. The preferentially selected TRBV5.1 and BV20 with the relatively conserved CDR3 motif may be potential targets for personalized treatments of chronic HBV infection.

Analysis of T Cell Receptor Vβ Diversity in Peripheral CD4+ and CD8+ T Lymphocytes Obtained From Patients With Chronic Severe Hepatitis B

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 Vβ repertoire of patients with chronic severe hepatitis B (CSHB) undergoes increased stimulation, and to identify conserved motifs in specific TCR Vβ 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 Vβ CDR3 was subsequently characterized using immune spectratyping. The TCR Vβ families exhibiting a CDR3 spectratype that underwent monoclonal expansion were sequenced.

RESULTS

The number of oligoclonal or monoclonal expansion TCR Vβ 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 Vβ5, Vβ7, Vβ9, Vβ12, and Vβ18 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 Vβ families. In addition, JB1S1 and JB2S7 region genes were present at a high frequency.

CONCLUSIONS

The CD4+ and CD8+ TCR Vβ 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.

Antigen-loaded MR1 tetramers define T cell receptor heterogeneity in mucosal-associated invariant T cells

Generation of antigen-loaded MR1 tetramers that specifically stain MAIT cells identifies heterogeneity in phenotypes and TCR repertoires in humans and mice.

Mucosal-associated invariant T cells (MAIT cells) express a semi-invariant T cell receptor (TCR) α-chain, TRAV1-2–TRAJ33, and are activated by vitamin B metabolites bound by the major histocompatibility complex (MHC)–related class I–like molecule, MR1. Understanding MAIT cell biology has been restrained by the lack of reagents to specifically identify and characterize these cells. Furthermore, the use of surrogate markers may misrepresent the MAIT cell population. We show that modified human MR1 tetramers loaded with the potent MAIT cell ligand, reduced 6-hydroxymethyl-8-d-ribityllumazine (rRL-6-CH₂OH), specifically detect all human MAIT cells. Tetramer⁺ MAIT subsets were predominantly CD8⁺ or CD4⁻CD8⁻, although a small subset of CD4⁺ MAIT cells was also detected. Notably, most human CD8⁺ MAIT cells were CD8α⁺CD8β^−/lo, implying predominant expression of CD8αα homodimers. Tetramer-sorted MAIT cells displayed a T_H1 cytokine phenotype upon antigen-specific activation. Similarly, mouse MR1–rRL-6-CH₂OH tetramers detected CD4⁺, CD4⁻CD8⁻ and CD8⁺ MAIT cells in Vα19 transgenic mice. Both human and mouse MAIT cells expressed a broad TCR-β repertoire, and although the majority of human MAIT cells expressed TRAV1-2–TRAJ33, some expressed TRAJ12 or TRAJ20 genes in conjunction with TRAV1-2. Accordingly, MR1 tetramers allow precise phenotypic characterization of human and mouse MAIT cells and revealed unanticipated TCR heterogeneity in this population.

Effect of Hejie decoction on T cell immune state of chronic hepatitis B patients

AIM: To explore the effect of Hejie decoction (HJD) (mediation decoction) on T cellular immune state of chronic hepatitis B patients.

METHODS: Sixty-five patients with chronic hepatitis B were randomly divided into 2 groups. Forty patients in the treatment group were treated by HJD, and 25 patients in the control group were treated by routine Western medicine. The TCRVβ₇ gene expression, T lymphocyte subsets (CD₃⁺, CD₄⁺, CD₈⁺, CD₄⁺/CD₈⁺) levels were observed before and after treatment.

RESULTS: The level of CD₄⁺ cells was lower whereas the level of CD₈⁺ cells was higher in patients than in the normal group. There was no significant difference between the levels of CD₃⁺ cells in patients and normal persons. After 6 months of treatment, ALT, AST, TB levels of the 2 groups were obviously decreased, and the level of CD₄⁺ cells was increased whereas the level of CD₈⁺ cells was decreased in the treatment group. However, the level of CD₄⁺ cells and CD₈⁺ cells had no significant difference in the control group. TCRVβ₇ expressions were detected in 6 patients of the treatment group, whose HBV-DNA and HBeAg turned negative and ALT became normal. HBeAg in another 3 patients turned negative while HBV-DNA did not, and TCRVβ₇ expressions were not detectable. TCRVβ₇ expression could not be detected in the control group, HBV-DNA of the control group did not turn negative. HBeAg in 1 patient turned negative while HBV-DNA did not, and TCRVβ₇ expressions were not detectable. The total effective rate was not significantly different between the 2 groups and the markedly effective rate was significantly different (P < 0.01).

CONCLUSION: HJD is effective for treating chronic hepatitis B, and its effect seems to relate with the improvement of the TCRVβ₇ expression of chronic hepatitis B patients, thus activating T cells and eliminating HBV. T cellular immune function plays an important role in HBV infection and virus elimination.