T cell receptor (TCR) Vbeta gene usage in bronchoalveolar lavage and peripheral blood T cells from asthmatic and normal subjects

T Cell Repertoire During Ontogeny and Characteristics in Inflammatory Disorders in Adults and Childhood

Since the first day of life, a newborn has to deal with various pathogens from the environment. While passive immune protection is provided by diaplacental maternal antibodies, the development of cellular immunity is ongoing. A mature immune system should be able not only to defend against pathogens, but should also be able to differentiate between self- and non-self-antigens. Dysregulation in the development of cellular immunity can lead to severe disorders like immunodeficiency, autoimmunity and chronic inflammation. In this review, we explain the role of T cell immunity in antigen detection and summarize the characteristics of a mature TCR repertoire as well as the current state of knowledge about the development of the TCR repertoire in ontogenesis. In addition, methods of assessments are outlined, with a focus on the advantages and disadvantages of advanced methods such as next generation sequencing. Subsequently, we provide an overview of various disorders occuring in early childhood like immunodeficiencies, autoimmunity, allergic diseases and chronic infections and outline known changes in the TCR repertoire. Finally, we summarize the latest findings and discuss current research gaps as well as potential future developments.

T cell receptor-Vβ repertoires in lung and blood CD4+ and CD8+ T cells of pulmonary sarcoidosis patients

Background

Sarcoidosis patients have accumulations of activated CD4⁺ T cells in affected organs, such as the lungs. T cell receptor (TCR) Vβ-chain usage has been incompletely characterized in these patients.

Methods

We surveyed the TCR Vβ usage in CD4⁺ and CD8⁺ T cells in bronchoalveolar lavage (BAL) cells and peripheral blood mononuclear cells (PBMC) from 15 HLA-typed Scandinavian sarcoidosis patients. In addition, PBMC from 9 healthy volunteers and BAL cells from three of them were examined. Using 21 Vβ family-specific antibodies, we covered approximately 70% of all Vβ chains.

Results

In BAL T cells from sarcoidosis patients, we identified 16 CD4⁺ T cell expansions in 271 analyses (5.9%) and 21 CD8⁺ expansions in 240 analyses (8.7%). In PBMC we found 9 CD4⁺ expansions in 276 analyses (3.3%) and 12 CD8⁺ expansions out of 263 analyses (4.6%). Consistent with previous studies we found Vβ8 and Vβ16 expansions in sarcoidosis patients’ lungs. In addition, we found lung restricted Vβ22 expansions in three HLA DRB1 03⁺ patients. However, we found no statistically significant difference in frequency of expansions between patients and healthy controls.

Conclusions

The identified T cell expansions in present study indicate specific antigen recognition in the lungs of sarcoidosis patients.

Rapid αβ T-cell responses orchestrate innate immunity in response to Staphylococcal enterotoxin A

In the generation of a traditional immune response against invading pathogens, innate cells guide T cells by programming their differentiation. However, here we demonstrate that αβ T cells have an essential role in priming innate immunity in the lung after Staphylococcus aureus enterotoxin A (SEA) inhalation. We found that SEA induces waves of cellular activation, cytokine production, and migration into the lung tissue and airways. However, this innate response was completely inhibited in the absence of αβ T cells. Specifically, we found that interleukin (IL)-17A was required for the recruitment of neutrophils and monocytes into the lung. The cellular source of IL-17A was γδ T cells, which increased their IL-17A production following SEA but only in an αβ T-cell-dependent manner. Thus, rapid T-cell activation orchestrates innate immunity and may be a new point of therapeutic intervention for acute lung injury.

Characterization of the Interstitial Lung and Peripheral Blood T Cell Receptor Repertoire in Cigarette Smokers

T lymphocytes modulate the pulmonary inflammatory response. The aim of this study was to evaluate the clonality within the interstitial lung and peripheral blood T cell receptor (TCR) repertoire in smokers. Interstitial T lymphocytes were isolated from surplus tissue of 16 patients (63 +/- 9 [+/- SD] yr old, 11 male) undergoing surgery due to lung cancer (n = 15) or emphysema. TCR clonality was assessed by PCR amplification followed by spectratyping. Nearly all TCR of interstitial lung lymphocytes showed oligoclonal bands (CD4(+) subset 13/16 patients, 81%; CD8(+) 100%) indicating a specific differentiation. Peripheral blood T lymphocytes (PBL) TCR (especially CD4(+)) had less oligoclonal bands (CD4(+) 31%, CD8(+) 88%). Likewise, more oligoclonal bands were seen in lung TCR (total of 168 bands; 37 CD4(+); 131 CD8(+)), compared with 59 bands in PBL TCR (13 CD4(+); 46 CD8(+)). Intraindividual comparison revealed a more prominent difference in TCR oligoclonality between lung and blood in CD8(+) T cells (median of difference lung minus blood 5; interquartile range 1-10; P = 0.002) compared with CD4(+) T cells (median 2, 0-3, P = 0.039). Thus, TCR oligoclonality is preferentially found in the CD8(+) T cell subset, most distinctive in the lung. These findings indicate a specific interstitial T cell differentiation in response to local stimuli.

The clinical and biological overlap between Nijmegen Breakage Syndrome and Fanconi anemia

Fanconi anemia (FA), an autosomal recessive chromosomal instability syndrome, is characterized clinically by developmental abnormalities, growth retardation, progressive bone marrow failure, pancytopenia, and pronounced cancer predisposition. Nijmegen Breakage Syndrome (NBS) is a related disorder that shares overlapping clinical features, principally, developmental delay, microcephaly, and cancer predisposition. The diagnosis has relied on chromosomal instability following exposure to DNA cross-linking agents in FA and to ionizing radiation (IR) in NBS. We describe two patients who clinically had FA, but showed sensitivity to both DNA cross-linking agents and ionizing radiation, and who were found to have a rare mutation in the NBS gene. The importance of genetic diagnosis with respect to treatment and prognosis is discussed.

Diagnostic role of tests for T cell receptor (TCR) genes

Rapid advances in molecular biological techniques have made it possible to study disease pathogenesis at a genomic level. T cell receptor (TCR) gene rearrangement is an important event in T cell ontogeny that enables T cells to recognise antigens specifically, and any dysregulation in this complex yet highly regulated process may result in disease. Using techniques such as Southern blot hybridisation, polymerase chain reaction, and flow cytometry it has been possible to characterise T cell proliferations in malignancy and in diseases where T cells have been implicated in the pathogenesis. The main aim of this article is to discuss briefly the process of TCR gene rearrangement and highlight the disorders in which expansions or clonal proliferations of T cells have been recognised. It will also describe various methods that are currently used to study T cell populations in body fluids and tissue, their diagnostic role, and current limitations of the methodology.

Simultaneous analysis of T cell clonality and cytokine production in rheumatoid arthritis using three-colour flow cytometry

In this study we examined the cytokine production by T cells and TCRVbeta subsets in peripheral blood (PB) and synovial fluid (SF) from six RA patients and PB from 10 normal subjects, using three-colour flow cytometry. In two RA subjects we assessed T cell clonality by RT PCR using TCRBV family-specific primers and analysed the CDR3 (complementarity determining region 3) length by GeneScan analysis. A high percentage of IFN-gamma- and IL-2- producing cells was observed among the PB T cells in both the RA patients and normal controls and among the SF T cells in RA patients. In contrast, the percentage of T cells producing IL-4 and IL-5 was small among PB T cells in both RA patients and normal controls and among SF T cells in RA patients. There was no significant difference in the production of IFN-gamma, IL-2 and IL-5 between the two compartments (PB and SF); however, there were significantly more IL-4-producing cells in SF. Molecular analysis revealed clonal expansions of four TCRBV families in SF of two of the RA patients studied: TCRBV6.7, TCRBV13.1 and TCRBV22 in one and TCRBV6.7, TCRBV21.3 and TCRBV22 in the second. These expansions demonstrated cytokine expression profiles that differed from total CD3+ cells, implying that T cell subsets bearing various TCR-Vbeta families may have the potential to modulate the immune response in RA patients.

Conserved CDR 3 region of T cell receptor BV gene in lymphocytes from bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is an inflammatory lung disease characterized by the accumulation of inflammatory cells and deposition of collagen, resulting in lung remodelling. High numbers of T cells are present in bronchoalveolar lavage fluid (BALF) of IPF patients, although the characteristics of these cells are yet to be determined. To elucidate the pathogenic mechanisms of IPF, we analysed the T cell receptor (TCR) of BALF lymphocytes in three patients with IPF and three healthy subjects as control. TCR repertoire of BALF lymphocytes and T cell clonality were examined by family PCR and Southern blot analysis, and single-strand conformation polymorphism (SSCP), respectively. We observed that the TCR repertoire in the lung was heterogeneous, both in the control subjects and three patients with IPF. SSCP analysis demonstrated an increase in the number of accumulated T cell clones in BALF of two of the three patients, but not in the healthy subject. Furthermore, junctional sequence analysis showed the presence of conserved amino acid motifs (ETGRSG, LAxG, QGQ, GxQP, GRxG, VAR, PGT, GTI, GGT, TGR, LxLxQ, SGQ) in the TCR-CDR 3 region of BAL lymphocytes in patients with IPF, whereas only two amino acid motifs (VTTG, GGE) were found in the control. Our findings suggest that T cells in BALF of patients with IPF expand oligoclonally in the lung, suggesting antigen stimulation of these cells.

TCR usage and cytokine expression in peripheral blood and BAL T cells

T cells are thought to play an important regulatory role in atopic asthma. We hypothesized that human blood and BAL T cell subsets bearing various TCR-Vbeta genes might show selective differences in their cytokine profile. Peripheral blood (PB) and bronchoalveolar lavage (BAL) T cells from seven atopic asthmatic and six non-atopic non-asthmatic subjects were stimulated with PMA and ionomycin in the presence of monensin and analysed for TCR-Vbeta expression and production of cytokines at the single cell level. The percentage of IFN-gamma- and IL-2-producing BAL T cells was elevated compared with PB T cells from both the asthmatic subjects and the non-atopic, non-asthmatic controls. A small percentage of PB and BAL T cells produced IL-4 and IL-5, in asthmatic and normal subjects. In peripheral blood, the percentage of T cells expressing each cytokine was similar in the various TCR-Vbeta subsets and in total CD3+ T cells in all normal and six of seven asthmatic subjects. However, there was a substantial degree of heterogeneity in the cytokine profile of BAL TCR-Vbeta subsets compared with the total CD3+ T cells. This was more obvious in the asthmatic subjects with a reduction in the percentage of IFN-gamma- and IL-2-expressing T cells (five of seven asthmatic subjects) and an increase in the percentage of IL-4- and IL-5-expressing T cells (two of seven asthmatic subjects). These data confirm previous findings of an elevated proportion of IFN-gamma- and IL-2-producing BAL T cells while only a small proportion of PB and BAL T cells produce IL-4 and IL-5. Moreover, subsets of BAL T cells, defined by their TCR-Vbeta usage, may differ in their cytokine profile compared with the total CD3+ T cells, implying that T cells expressing different Vbeta elements may play different roles in regulating the airway inflammation in asthma.

Molecular and flow cytometric analysis of the Vbeta repertoire for clonality assessment in mature TCRalphabeta T-cell proliferations

Clonality assessment through Southern blot (SB) analysis of TCRB genes or polymerase chain reaction (PCR) analysis of TCRG genes is important for diagnosing suspect mature T-cell proliferations. Clonality assessment through reverse transcription (RT)-PCR analysis of Vbeta-Cbeta transcripts and flow cytometry with a Vbeta antibody panel covering more than 65% of Vbeta domains was validated using 28 SB-defined clonal T-cell receptor (TCR)alphabeta(+) T-ALL samples and T-cell lines. Next, the diagnostic applicability of the V(beta) RT-PCR and flow cytometric clonality assays was studied in 47 mature T-cell proliferations. Clonal Vbeta-Cbeta RT-PCR products were detected in all 47 samples, whereas single Vbeta domain usage was found in 31 (66%) of 47 patients. The suspect leukemic cell populations in the other 16 patients showed a complete lack of Vbeta monoclonal antibody reactivity that was confirmed by molecular data showing the usage of Vbeta gene segments not covered by the applied Vbeta monoclonal antibodies. Nevertheless, this could be considered indirect evidence for the "clonal" character of these cells. Remarkably, RT-PCR revealed an oligoclonal pattern in addition to dominant Vbeta-Cbeta products and single Vbeta domain expression in many T-LGL proliferations, providing further evidence for the hypothesis raised earlier that T-LGL derive from polyclonal and oligoclonal proliferations of antigen-activated cytotoxic T cells. It is concluded that molecular Vbeta analysis serves to assess clonality in suspect T-cell proliferations. However, the faster and cheaper Vbeta antibody studies can be used as a powerful screening method for the detection of single Vbeta domain expression, followed by molecular studies in patients with more than 20% single Vbeta domain expression or large suspect T-cell populations (more than 50%-60%) without Vbeta reactivity.

T cell receptor Vbeta expression in patients with allergic asthma before and after repeated low-dose allergen inhalation

The objective of this study was to identify disease-associated T cell subsets by characterizing the lung and blood T cell receptor (TCR) repertoires in allergic asthmatics before and after repeated low-dose allergen challenge. Peripheral blood lymphocyte (PBL) and bronchoalveolar lavage (BAL) samples were obtained from eight patients with allergic asthma before and after a period of repeated low-dose allergen inhalations. RT-PCR followed by Southern blot allowed the quantification of relative Vbeta gene segment usage. Thirteen healthy individuals served as controls at PBL level. PBL as well as BAL T cells of asthmatics displayed a higher usage of Vbeta3, Vbeta5.2, and Vbeta6.1-3 and a lower usage of Vbeta16, Vbeta18, and Vbeta19 compared to PBL of healthy controls. Interestingly, TCR Vbeta7 and Vbeta9 usage was significantly higher in BAL than in PBL in asthmatics before as well as after challenge. TCR repertoire alterations after allergen challenge differed between individuals, with relatively mild changes.

Modification of T-cell receptor Vbeta repertoire in response to allergen stimulation in peanut allergy

BACKGROUND

Peanut is one of the most common foods causing allergic reactions and is the most common cause of fatal and near-fatal food-related anaphylaxis. Little is known of the immunologic mechanisms that underlie peanut allergy.

OBJECTIVES

In this study we examined clonality of the T-cell response (TCR) to peanut in MHC class II identical, peanut allergy-discordant sibling pairs.

METHODS

Four sibling pairs were investigated. The TCR repertoire was analyzed before and after in vitro stimulation of PBMCs with crude peanut or PHA, as control for general/nonspecific reactivity. Eighteen TCR-Vbeta families were examined by flow cytometry. Where significant differences in incidence of particular TCR-Vbeta families were observed, PCR familyspecific cDNA amplification and gene scanning were performed.

RESULTS

After stimulation with peanut, no selective expansion of any TCR-Vbeta subpopulation was observed with flow cytometry, in either the peanut-allergic or nonallergic siblings, with the exception of 1 peanut-allergic subject who demonstrated a significant increase of TCR-Vbeta11(+) cells (0.3%-5.9% of the total CD3(+) cells). However, gene scanning revealed predominant single-size PCR products for TCRBV11 in all peanut-allergic subjects after peanut stimulation. TCRBV11 polyclo-nality was observed in allergic and nonallergic subjects before peanut stimulation and in nonallergic subjects after peanut stimulation. In comparison, all subjects, before and after stimulation with peanut, showed polyclonality for TCRBV2.

CONCLUSIONS

Our results argue for clonal or oligoclonal TCRs to crude peanut and indicate that changes in the TCRBV11 subpopulation are restricted to peanut-allergic subjects after stimulation with crude peanut allergen.

Flow cytometric analysis of the Vbeta repertoire in healthy controls

BACKGROUND

Analysis of the T-cell receptor (TCR)-Vbeta repertoire has been used for studying selective T-cell responses in autoimmune disease, alloreactivity in transplantation, and protective immunity against microbial and tumor antigens. For the interpretation of these studies, we need information about the Vbeta repertoire usage in healthy individuals.

METHODS

We analyzed blood T-lymphocyte (sub)populations of 36 healthy controls (age range: from neonates to 86 years) with a carefully selected most complete panel of 22 Vbeta monoclonal antibodies, which together recognized 70-75% of all blood TCRalphabeta(+) T lymphocytes. Subsequently, we developed a six-tube test kit with selected Vbeta antibody combinations for easy and rapid detection of single ("clonal") Vbeta domain usage in large T-cell expansions.

RESULTS

The mean values of the Vbeta repertoire usage were stable during aging in blood TCRalphabeta(+) T lymphocytes as well as in the CD4(+) and CD8(+) T-cell subsets, although the standard deviations increased in the elderly. The increased standard deviations were caused by the occurrence of oligoclonal T-cell expansions in the elderly, mainly consisting of CD8(+) T lymphocytes. The 15 detected T-cell expansions did not reach 40% of total TCRalphabeta(+) T lymphocytes and represented less than 0.4 x 10(9) cells per liter in our study. Vbeta usage of the CD4(+) and CD8(+) subsets was comparable for most tested Vbeta domains, but significant differences (P < 0.01) between the two subsets were found for Vbeta2, Vbeta5.1, Vbeta6.7, Vbeta9.1, and Vbeta22 (higher in CD4(+)), as well as for Vbeta1, Vbeta7.1, Vbeta14, and Vbeta23 (higher in CD8(+)). Finally, single Vbeta domain expression in large T-cell expansions can indeed be detected by the six-tube test kit.

CONCLUSIONS

The results of our study can now be used as reference values in studies on distortions of the Vbeta repertoire in disease states. The six-tube test kit can be used for detection of single Vbeta domain expression in large T-cell expansions (>2.0 x 10(9)/l), which are clinically suspicious of T-cell leukemia.