Molecular features of the complementarity determining region 3 motif of the T cell population and subsets in the blood of patients with chronic severe hepatitis B

Functional analysis of the antigen binding sites on the MTB/HIV-1 peptide bispecific T-cell receptor complementarity determining region 3α

OBJECTIVE

Mycobacterium tuberculosis /human immunodeficiency virus (MTB/HIV) coinfection has become an urgent problem in the field of prevention and control of infectious diseases in recent years. Adoptive cellular immunotherapy using antigen-specific T-cell receptor (TCR) engineered T cells which recognize the specific antigen artificially may have tremendous potential in anti-MTB/HIV coinfection. We have previously successfully identified a MTB Ag85B 199-207 and HIV-1 Env 120-128 peptide-bispecific TCR screened out from peripheral blood mononuclear cells of a HLA-A∗0201 + healthy individual and have further studied that how residues on the predicted complementarity determining region (CDR) 3 of the β chain contribute to the bispecific TCR contact with the peptide-MHC. However, it is not clear which amino acids in the predicted CDR3α of the bispecific TCR play a crucial role in ligand recognition.

METHODS

The variants in the CDR3α of the bispecific TCR were generated using alanine substitution. We then evaluated the immune effects of the five variants on T-cell recognition upon encounter with the MTB or HIV-1 antigen.

RESULTS

Mutation of two amino acids (E112A, Y115A) in CDR3α of the bispecific TCR caused a markedly diminished T-cell response to antigen, whereas mutation of the other three amino acids (S113A, P114A, S116A) resulted in completely eliminated response.

CONCLUSION

This study demonstrates that Ser 113 , Pro 114 and Ser 116 in CDR3α of the bispecific TCR are especially important for antigen recognition. These results will pave the way for the future development of an improved high-affinity bispecific TCR for use in adoptive cellular immunotherapy for MTB/HIV coinfected patients.

Human immune repertoire in hepatitis B virus infection

Hepatitis B virus (HBV) infection is a public health threat that affects 257 million people worldwide and can progress to liver cirrhosis, liver failure, and hepatocellular carcinoma. The HBV antigen- induced adaptive immune response plays an important role in HBV clearance. Immune repertoire sequencing (IRS) has been used to investigate the molecular mechanisms behind the immune system, find novel ways to treat HBV infection, and evaluate the genetic responses and immune characteristics of individuals infected by HBV or immunized by HBV vaccine. This review summarizes the human immune repertoire analysis methodology, and the application of the IRS in the prediction of HBV infection progression, treatment, and vaccination.

Mucosal-associated invariant T-cells are severely reduced and exhausted in humans with chronic HBV infection

Chronic hepatitis B virus (CHBV) infection is a major cause of liver diseases. Mucosal-associated invariant T (MAIT) cells are important for antiviral immunity in the liver, but the distinction between intrasinusoidal and peripheral MAIT cells in patients with CHBV infections remains unclear. PBMCs were obtained from patients with CHBV infections (n = 29) and age-matched controls (n = 46). Liver-associated mononuclear cells (LMCs) were collected from healthy donors (n = 29) and explanted livers (n = 19) from patients and used for phenotypic, functional and TCR diversity analyses. The percentages of both peripheral and intrasinusoidal MAIT cells were significantly reduced in the CHBV infection group compared to the control group. Peripheral MAIT cells from CHBV-infected patients expressed higher levels of HLA-DR, CD69, CD38 and PD-1 than those of controls. We also confirmed that peripheral MAIT cells in HBV patients had elevated expression T-cell exhaustion genes. Except for a difference in the level of PD-1, no differences were observed between the liver MAIT cells of the two groups. The production of IFN-α in peripheral MAIT cells of CHBV infection patients was lower than in control patients, but no such difference was observed in liver MAIT cells. Additionally, a distinct TCR signature was found in CHBV patients. Hence, we found distinct activities and functions in liver and peripheral MAIT cells of patients with CHBV infections.

Dynamic changes of T cell receptor repertoires in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND AND AIMS

T cell-mediated immune injury plays a critical role in the pathogenesis of hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). Given the high short-term mortality and crucial role of T cells in the disease progression, it is necessary to investigate the dynamics of T cell clones during HBV-ACLF. The aim of this study was to longitudinally investigate dynamic changes in the composition and perturbation of T cell receptor β (TCRβ) chain repertoires and to determine whether TCR repertoire characteristics were associated with HBV-ACLF patient outcomes.

METHODS

Peripheral blood mononuclear cells (PBMCs) were collected at two time points from 5 HBV-ACLF patients. Global CD4⁺ and CD8⁺ T cells were sorted using magnetic beads. TCRβ complementarity-determining region 3 was analyzed by unbiased high-throughput sequencing.

RESULTS

During HBV-ACLF, there was a significant decrease in the diversity of T cell repertoires and an increase in proportion of the most 100 abundant clonotypes of CD8 T cells but not CD4. Decreased CD8 repertoire diversity was positively correlated with the reduction of the Model for End-Stage Liver Disease (MELD) score.

CONCLUSIONS

There was significant clonal expansion in CD8 but not in CD4 T cell repertoires in HBV-ACLF patients during disease progression. Patients with greater clonal expansions in CD8 T cell repertoires may have better outcomes. CD8 TCRβ repertoire diversity may serve as a potential predictive marker for disease outcome.

TCR Vβ Usage of Peripheral Blood and Liver Infiltrating Lymphocytes in Patients with Chronic Hepatitis B

INTRODUCTION

Chronic hepatitis B (CHB) is still a public health problem and its mechanism remains unclear. In this study, we detect the skewness of T cell receptor beta chain variable gene (TCR Vβ) in peripheral blood lymphocytes (PBL) and the liver infiltrating lymphocytes (LIL) of patients with CHB; and hope to provide information for further research on the pathogenic mechanism of CHB.

MATERIAL AND METHODS

Fifteen patients with CHB, ten healthy volunteers and three patients with liver cysts were recruited as the subjects. The usage of TCR Vβ of PBL and LIL were measured and compared; the associations of the TCR Vβ usage of PBL with some hematological indices, including human leukocyte antigen (HLA) alleles, percents of CD4+ and CD8+ T cells, sera levels of HBV-DNA and IFN-γ, were analyzed.

RESULTS

In PBL, Vβ12 and Vβ13.1 were the highest predominant usage genes which usage frequencies were all 46.7%; Vβ23 was the key limited usage gene (40.0%). In LIL, the mainly predominant and limited usage gene was Vβ13.1 (73.3%) and Vβ23 (46.7%), respectively. About half of the patients with CHB with HLA-DR9 or HLA-DR12 showed the predominant usage of Vβ5.2 or Vβ13.2. In patients with CHB, the percentage of CD4+ T cells was 33.41 ± 5.39 %, that of CD8+ T cells was 28.67 ± 6.77 %; the concentration of IFN-γ was 182.52 ± 44.16 pg/mL. Compared to the healthy controls, there were significant differences for these data (P < 0.05). Neither ALT nor HBV-DNA was relative to the usage of TCR Vβ.

CONCLUSIONS

PBL and LIL share the common sknewness of TCR Vβ genes, which probably relates to some hematological indices. However, the roles of such similarities and associations in the development of CHB need further study.

Dynamic Perturbations of CD4 and CD8 T Cell Receptor Repertoires in Chronic Hepatitis B Patients upon Oral Antiviral Therapy

Long-term treatment with nucleos(t)ide analogs (NUCs) can improve the antiviral T cell response in chronic hepatitis B (CHB) patients. Whether and to what extent the T cell response is improved by NUCs in the early stage leading to hepatitis B e antigen (HBeAg) seroconversion remain to be clarified. A total of 22 CHB patients undergoing 2-year telbivudine-based therapy were enrolled, including 10 exhibiting a complete response (CR) and 12 exhibiting a non-complete response (NCR) according to HBeAg seroconversion at week 52. Peripheral CD4⁺ and CD8⁺ T cells were sorted at baseline, weeks 12, and 24. The T cell receptor β chain (TCRβ) complementarity-determining region 3 was analyzed by unbiased high-throughput sequencing. Compared with NCR group, patients in CR group had a much lower percentage of persistent clonotypes (P < 0.001) but remarkably higher percentages of new and expanded clonotypes (P < 0.05) between any two time points for both CD4 and CD8 subsets. The CD4 T cells exhibited a stronger response than CD8 population in the patients. The number of new and expanded clonotypes was inversely associated with the decline of viral antigen. In conclusion, NUC-based therapy induces a broad and vigorous T cell response with rapid decline of antigenemia during the early stage of treatment. A broad T cell expansion is crucial for HBeAg seroconversion. Our findings suggest that the potent suppression of hepatitis B virus replication by NUC monotherapy complemented with additional immunomodulatory strategies may increase the likelihood of a functional cure for CHB in the future.

Relationship between T-cell receptor beta chain sequences and human cytomegalovirus infection in allogeneic hematopoietic stem cell transplant recipients

In the present study, clonal amplifications of T-cell receptor β variable (TCR BV) linked to human cytomegalovirus (HCMV) infection were detected in recipients of allogeneic hematopoietic stem cell transplants (HSCT), and certain relationships between them were identified. Furthermore, the relationship between TCR BV sequences and HCMV infections was investigated. The results indicated that the 3 recipients of HSCT had monoclonal expansion of specific TCR BV clones following HSCT. Among these recipients, 2 suffered from pp65 and immediate early (IE) antigenemia. These patients demonstrated preferential expansion of TCR BV9 (QVRGGTDTQ) and TCR BV11 (VATDFQ). The remaining recipient did not express TCR BV9 and TCR BV11, nor did this individual have pp65 and IE antigenemia. These results suggest that expression of TCR BV9 and TCR BV11 may be associated with HCMV antigenemia, and may be involved in the immune response. The amino acid sequences 'QVRGGTDTQ' and 'VATDFQ' may be involved in HCMV reactivation in patients who have undergone HSCT. Assessment of the TCR BV families may provide valuable insight into HCMV pathogenesis and may aid in the diagnosis and therapy for HSCT recipients infected with HCMV.

High-Throughput Analysis of the T Cell Receptor Beta Chain Repertoire in PBMCs from Chronic Hepatitis B Patients with HBeAg Seroconversion

T lymphocytes are the most important immune cells that affect both the development and treatment of hepatitis B. We used high-throughput sequencing to determine the diversity in the V and J regions of the TCRβ chain in 4 chronic hepatitis B patients before and after HBeAg seroconversion. Here, we demonstrate that the 4 patients expressed Vβ12-4 at the highest frequencies of 10.6%, 9.2%, 17.5%, and 7.5%, and Vβ28 was the second most common, with frequencies of 7.8%, 6.7%, 5.3%, and 10.9%, respectively. No significant changes were observed following seroconversion. With regard to the Jβ gene, Jβ2-1 was the most commonly expressed in the 4 patients at frequencies of 5.8%, 6.5%, 11.3%, and 7.3%, respectively. Analysis of the V-J region genes revealed several differences, including significant increases in the expression levels of V7-2-01-J2-1, V12-4-J1-1, and V28-1-J1-5 and a decrease in that of V19-01-J2-3. These results illustrate the presence of biased TCRVβ and Jβ gene expression in the chronic hepatitis B patients. TRBVβ12-4, Vβ28, Jβ2-1, V7-2-01-J2-1, V12-4-J1-1, and V28-1-J1-5 may be associated with the development and treatment of CHB.

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.

Molecular characterization of T cell receptor beta variable in the peripheral blood T cell repertoire in subjects with active tuberculosis or latent tuberculosis infection

Background

T cells are closely linked to the clinical manifestations of subjects with Mycobacterium tuberculosis (MTB) infection. T cell receptor beta variable (TCRBV) is a signal and indicative molecule on the membrane of T lymphocytes, reflecting the composition and specificity of T cells. The molecular profiles of TCRBV in peripheral blood mononuclear cells (PBMCs) and their subpopulations (CD4⁺ and CD8⁺ T cells) from subjects with active tuberculosis (TB) or latent TB infection (LTBI) have not been well described.

Methods

In 42 subjects with active TB or LTBI, PMBCs and their subsets were separated and sorted. The molecular profiles of the TCRBV complementarity determining region 3 (CDR3) in the three cell populations were investigated using our recently developed gene melting spectral pattern (GMSP) assay. The TCRBV members were then cloned and sequenced when their GMSP image profiles showed a single-peak.

Results

The average number of skewed TCRBV molecules in the CD4⁺ cell subset was significantly higher than that in PBMCs and CD8⁺ T cells. TCRBV12, BV13.1, BV13.2, and BV24 were expressed more prevalently than other TCRBV gene families in the three cell populations. In addition, relatively conserved amino acid motifs were identified in TCRBV5.1 and BV20 CDR3 in PBMCs and its subsets. The monoclonal TCRBV14 and BV23 expressed were different between active TB and LTBI subjects.

Conclusions

These results indicate that the T cell immune response is complex and multi-specific in active TB and LTBI subjects. Analysis of TCRBV expression in CD4⁺ T cells suggest that it could be useful in assessing the composition and status of circulating T cells. Furthermore, the expression of TCRBV14, BV23 and the sequencing of CDR3 amino acid motifs of TCRBV5.1, BV20 could be used in the differential diagnosis and treatment of subjects with active TB or LTBI.

Limited T cell receptor beta variable repertoire responses to ESAT-6 and CFP-10 in subjects infected with Mycobacterium tuberculosis

Mycobacterium tuberculosis (MTB)-specific antigens, ESAT-6 or CFP-10 play a key role in diagnosis and control MTB infection. T cell receptor (TCR) reflects the status and function of T cells. However, the features of the TCR beta variable (TCRBV) repertoire used against ESAT-6 and CFP-10 from MTB subjects have not been well described. The molecular profiles of TCRBV complementarity-determining region 3 (CDR3) in PBMCs with or without ESAT-6 or CFP-10 stimulation were assayed using a gene melting spectral pattern (GMSP) assay developed in our previous study. The average number of skewed TCRBV family in PBMCs stimulated with ESAT-6 or CFP-10 was significantly higher than that in unstimulated PBMCs. TCRBV3, BV5.1, BV12, BV13.1, BV13.2, BV20 and BV24 were used more frequently than other TCRBV members in PBMCs from MTB subjects, and TCRBV3, BV5.1 in stimulated PBMCs have a preference in the usage of variable (V) and joining (J) segments and CDR3. The results indicate that the T cell immune response in MTB subjects involves a few of specific T cells. The preferred usage of certain V and J segments and CDR3s of TCRBV3 or BV5.1 may be related to ESAT-6 or CFP-10 respectively, which would help clinical differential diagnosis and treatment of MTB-infected subjects.

Phenotypes and clinical significance of circulating CD4(+)CD25(+) regulatory T cells (Tregs) in patients with acute-on-chronic liver failure (ACLF)

BACKGROUND

CD4(+)CD25(+) regulatory T cells (Tregs) play an important role in maintaining immunological tolerance to self and foreign antigens. T cell receptors (TCR) reflect the composition and function of T cells. It is not universally agreed that there is a relationship between CD4(+)CD25(+) Treg frequency and the severity of acute-on-chronic liver failure (ACLF). The repertoire of TCR beta chain variable (TCRBV) regions of peripheral Tregs in ACLF patients is not well understood.

METHODS

Human PBMCs were separated and sorted into CD4(+)CD25(+) Treg subsets using density gradient centrifugation and magnetic activated cell sorting (MACS). The CD4(+)CD25(high) Treg frequency in peripheral blood of ACLF and chronic hepatitis B (CHB) patients was measured by flow cytometry. The molecular profiles of TCRBV CDR3 were determined using gene melting spectral pattern (GMSP) analysis. TCRBV gene families were cloned and sequenced when the GMSP profiles showed a single-peak.

RESULTS

CD4(+)CD25(high) Treg prevalence in peripheral blood of ACLF patients is increased significantly compared to healthy donors (HDs) (P < 0.01) and CHB patients (P < 0.01). The prevalence of CD4(+)CD25(high) Tregs in ACLF or CHB patients is positively correlated with HBV DNA load. The TCRBV11, BV13.1, BV18, BV20 are the most prevalent TCRBV in CD4(+)CD25(+) Tregs in ACLF and CHB patients. In addition, the CDR3 motifs were relatively conserved in these four TCRBV gene families.

CONCLUSIONS

The CD4(+)CD25(high) Tregs prevalence in peripheral blood is indicative of disease severity in ACLF or CHB patients. The relatively conserved TCRBV20 CDR3 motif "TGTGHSPLH" and TCRBV11 CDR3 motif "VYNEQ" may be used in helping diagnosis and treat patients with ACLF.

Skewed T-cell receptor beta chain variable gene (TCRBV) usage among different clinical types of patients with chronic HBV infection

This study aimed to determine the degree of clonal expansion of T cells in peripheral blood mononuclear cells (PBMCs) isolated from patients suffering from different clinical types of hepatitis B (HB) infection and to analyse the clinical relevance of the skewed T-cell receptor beta variable (TCRBV). Sera and PBMCs were collected from 90 HB patients. Gene melting spectral pattern (GMSP) analysis was used to determine the distribution and expansion of populations expressing specific TCRBV complementary determined region 3 (CDR3) genes. TCRBV genes associated with monoclonal expansion were sequenced. TCRBV families from the majority of patients (80/90) displayed skewed T-cell expansion. Furthermore, TCRBV11, BV12 and BV13.1 were more frequent than other TCRBV genes; the sequence of TCRBV11 CDR3 was expressed as 'VYNEQ' in all patients and was accompanied by the BJ2.1 fragment. In patients with chronic HB, the frequency of skewed TCRBV was inversely correlated with hepatitis B virus (HBV) DNA levels. The persistently skewed TCRBV gene families in HB patients may be associated with the development and maintenance of hepatitis. GMSP analysis of TCRBV gene families may be helpful in estimating disease status, and BV11 may be associated with HBV replication in patients with chronic HBV infection.