Distinct patterns of T cell receptor distribution of peripheral blood CD8+ cells during different stages of chronic infection with hepatitis B virus

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.

Multiple myeloma patients at peripheral blood stem cell harvest: restricted usage of TCR beta variable families

The immune systems of multiple myeloma patients are suppressed by the disease itself, and this immunosuppression is further enhanced by standard therapies. The aim of our study was to evaluate the effects of initial chemotherapy and a peripheral blood mobilisation regimen on T-cell population diversity. Reverse transcription-polymerase chain reaction (RT-PCR) with a new set of primers, in combination with capillary electrophoresis, was established. The methodology was used to analyse the relative expression of 27 T-cell receptor beta variable gene families (BV families) in multiple myeloma patients undergoing peripheral blood stem cell harvest. We found that the overall BV family usage in these patients was restricted; the relative expression of 10 BV families was significantly depressed in patients compared to healthy donors. These findings demonstrate that the preparative regimen for autologous stem cell transplantation affects the T-cell population in terms of the restriction of its T-cell receptor diversity.

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.

Mycobacterium bovis BCG scar status and HLA class II alleles influence purified protein derivative-specific T-cell receptor V beta expression in pulmonary tuberculosis patients from southern India

Purified protein derivative (PPD) RT23-recalled T-cell receptor (TCR) V beta expression was studied in the peripheral blood of 42 pulmonary tuberculosis patients and 44 healthy controls from southern India, a region where tuberculosis is endemic. Forty-eight-hour whole-blood cultures in the presence or absence of PPD-RT23 were set up, and at the end of the culture period total RNA was extracted and cDNA was synthesized. Expression of various TCR V beta families was assessed by using family-specific primers. PPD-specific expression (usage) of TCR V beta families 4, 6, 8 to 12, and 14 was found in more controls than patients. Among the responders (individuals who showed PPD-specific expression), endemic controls had significantly higher responses than the patients had for TCR V beta families 2, 3, 7, 13, and 17. The majority of the patients did not show usage of most of the TCR V beta families, and this was attributed to T-cell downregulation. A four-way nested classification analysis revealed that TCR V beta family 1, 5, 9, 12, and 13 usage in the context of HLA class II high-risk alleles (DRB1*1501, DRB1*08, and DQB1*0601) and Mycobacterium bovis BCG scar status were the determining factors in susceptibility and resistance to tuberculosis. The healthier status of controls was attributed to the wider usage of many TCR V beta families readily recalled by PPD, while the disease status of the patients was attributed to TCR V beta downregulation and the resultant T-cell (memory cell?) unresponsiveness. Host genetics (HLA status) and BCG vaccination (scar status) seem to play important roles in skewing the immune response in adult susceptibility to pulmonary tuberculosis through TCR V beta usage.

Longitudinal analysis of the T-cell receptor (TCR)-VA and -VB repertoire in CD8+ T cells from individuals immunized with recombinant hepatitis B surface antigen

Recent studies have suggested that vaccination induces alterations in the T cell receptor (TCR) repertoire. We investigate the diversity of the TCR repertoire after immunization with a recombinant hepatitis B surface vaccine in seven healthy subjects in CD8+ T cells in peripheral blood lymphocytes. Cellular immune responses were monitored over time by sorting CD8 T cells followed by TCR-VA and -VB complementarity determining region 3 (CDR3) analysis. Frequency of individual VB families was determined by flow cytometry. TCR-VA/VB repertoires obtained from CD8+ T cells drawn after vaccination were compared to the TCR repertoire determined prior to vaccination. Monoclonal TCR transcripts could be detected exclusively in CD8+, but not in CD4+ T cells. Such monoclonal TCR transcripts were either stable in some individuals, or could only be detected at certain time points after vaccination. Sorting of monoclonal TCR-VB3+ T cells, which constituted up to 5% of the CD8+ T cell population from one individual, revealed that this T cell clone recognizes an epitope provided by the recombinant hepatitis B vaccine presented by MHC-class I on autologous antigen-presenting cells. Examination of the structural anatomy, defined by the TCR, and the frequency of T cells responding to the immunizing antigen may be helpful to provide surrogate markers to monitor cellular immune responses induced by protein antigens utilized for vaccination.

Differential expansion of T-cell receptor variable beta subsets after antigenic stimulation in patients with different outcomes of hepatitis C infection

Persistent antigenic stimulation during chronic hepatitis C may alter the T-cell receptor variable chain beta (TCR BV) repertoire as well as the cytokine responses of hepatitis C virus (HCV)-specific T lymphocytes. We analysed the distribution of the TCR BV subsets 2.1, 3.1, 5.1, 6.1, 8, 13.1, 13.6, 14.1, 17.1, 21.3 in relation to intracytoplasmic expression of interleukin-2, interferon-gamma, interleukin-4 and interleukin-10. Using flow cytometry, CD45RO+ memory T cells of 27 patients with chronic hepatitis C, eight patients with resolved HCV infection and 16 non-HCV-related controls were studied with and without stimulation by the HCV core, NS3, NS4, NS5a and NS5b proteins. Patients with chronic and resolved hepatitis C differed by larger basal TCR BV2.1+, BV6.1+, BV17.1+ and BV21.3+ subsets in chronic hepatitis C, which were correlated to the numbers of T cells with spontaneous interleukin-2 and interferon-gamma production (r=0.51-0.73, P<0.05). Upon HCV-specific stimulation these subsets did not expand, whereas a marked in vitro expansion of TCR BV8+ T cells in response to all HCV proteins was selectively noted in chronic hepatitis C (P<0.05). This expansion of TCR BV8+ memory T cells was significantly correlated to HCV-induced interleukin-10 expression (r=0.58-0.98, P<0.01). Thus, differential involvement of selected TCR BV subsets may be related to the outcome of HCV infection.

Analysis of the T-cell receptor beta-chain variable-region (Vbeta) repertoire in chronic human Chagas' disease

Previous studies have shown that infection with the protozoan Trypanosoma cruzi (Chagas' disease) is associated with genetic components [human leukocyte antigen (HLA) genes and T-cell receptor (TCR) genes]. We studied the TCR Vbeta repertoire of peripheral blood lymphocytes of 23 unrelated serologically positive subjects using reverse transcriptase-polymerase chain reaction (RT-PCR). The patients, previously tested for HLA genotypes, were clinically classified as asymptomatic, arrhythmic and cardiopathic patients. Statistical analysis showed the significant increment of the Vbeta7 family in chagasics with arrhythmia compared with asymptomatic and cardiopathic patients, indicating that the frequency of this family is variable in different clinical forms of the disease and possibly that these T cells might be a marker of the progression of Chagas' disease. Based on the calculation of a Delta score the order of variability in the TCR repertoire was: patients with heart failure > asymptomatic > arrhythmic patients. The major histocompatibility complex (MHC) of the individual may influence the use of particular V genes in T-cell response to foreign antigens. We found a significant increase of the Vbeta7 family in arrhythmic patients who were DRB1*01 DQB1*0501 DPB1*0401, a marker associated with susceptibility to cardiac damage in Chagas' disease. If confirmed by further studies in a larger cohort, a possible association between the TCR Vbeta repertoire and the MHC haplotype of chagasic patients could be postulated.

Highly altered V beta repertoire of T cells infiltrating long-term rejected kidney allografts

Chronic rejection represents a major cause of long-term kidney graft loss. T cells that are predominant in long-term rejected kidney allografts (35 +/- 10% of area infiltrate) may thus be instrumental in this phenomenon, which is likely to be dependent on the indirect pathway of allorecognition only. We have analyzed the variations in T cell repertoire usage of the V beta chain at the complementary determining region 3 (CDR3) level in 18 human kidney grafts lost due to chronic rejection. We observed a strongly biased intragraft TCR V beta usage for the majority of V beta families and also a very high percentage (55%) of V beta families exhibiting common and oligoclonal V beta-C beta rearrangements in the grafts of patients with chronic rejection associated with superimposed histologically acute lesions. Furthermore, V beta 8 and V beta 23 families exhibited common and oligoclonal V beta-J beta rearrangements in 4 of 18 patients (22%). Several CDR3 amino acid sequences were found for the common and oligoclonal V beta 8-J beta 1.4 rearrangement. Quantitative PCR showed that biased V beta transcripts were also overexpressed in chronically rejected kidneys with superimposed acute lesions. In contrast, T lymphocytes infiltrating rejected allografts with chronic rejection only showed an unaltered Gaussian-type CDR3 length distribution. This pattern suggests that late graft failure associated with histological lesions restricted to Banff-defined chronic rejection does not involve T cell-mediated injury. Thus, our observation suggests that a limited number of determinants stimulates the recipient immune system in long-term allograft failure. The possibility of a local response against viral or parenchymatous cell-derived determinants is discussed.

T cell response in xenorecognition and xenografts: a review

Xenotransplantation has recently become a subject of interest for the transplantation community due to the current organ shortage, which could be partially or even totally solved by the development of this strategy. The humoral response, which arises as a result of species disparities, is the major obstacle to the success of xenotransplantation. However, if the use of different strategies such as plasmapheresis, immunoadsorption, the utilization of organs from transgenic pigs for complement regulatory molecules and new immunosuppressive drugs, may allow to overcome or reduce the early antibody mediated rejections (hyperacute or acute vascular rejection), delayed responses based on cellular activations will still occur. In this review, despite the fact that different cell populations have been shown to be implicated in these phenomena (NK, granulocytes, macrophages), we will focus on recent published information concerning T cell response only, in xenorecognition.

T Cell Repertoire Alterations of Vascularized Xenografts

The role of T cells in the rejection of vascularized xenografts has been little explored. Because of the high potential diversity of xenoantigens, it has been suggested that xenotransplantation could induce a strong cellular response that could contribute to delayed rejection. Alternatively, alterations in molecular interactions could impair the T cell response. Because the analysis of TCR repertoire in vivo indirectly reflects the nature and the magnitude of T cell xenorecognition, we took advantage of the possibility of obtaining long term survival of hamster heart xenografts in rat recipients treated with a combination of cobra venom factor and cyclosporin A (CsA), to analyze T cell infiltration and, for the first time, Vβ TCR usage, at the complementarity-determining region 3 level, in accommodated and rejected xenografts, compared with allografts. After withdrawal of CsA (on day 40), the analysis of Vβ family expression and corresponding complementarity-determining region 3 lengths in rejected xenografts revealed a Gaussian pattern, in contrast to a much more restricted pattern in rejected allografts (p = 0.002), suggesting that, after withdrawal of CsA, all the underrepresented T cell clones are rapidly expanded in xenografts. These results correlate with the rapid kinetics of rejection (4 ± 1 days), the high number of T cells, the rapid expression of markers of activation (IL-2 receptor α-chain and class II receptor), and the strong deposit of IgG Abs in rejected xenografts. Taken together, these results suggest that the intensity and diversity of the T cell response to xenografts could be stronger than the response to allografts in vivo.