Expression of the human V beta 8 gene product preferentially correlates with class II major histocompatibility complex restriction specificity

T-cell receptor repertoire in hereditary hemochromatosis: a study of 32 hemochromatosis patients and 274 healthy subjects

Low CD8(+) T lymphocyte numbers have contributed to deciphering the genotype/phenotype discrepancies found in hereditary hemochromatosis (HH) patients genotyped for the Hfe mutations, C282Y and H63D. In this study, we extend the analysis of T lymphocytes in HH to the T cell receptor (TcR) repertoire. Thirty-two HH patients (C282Y homozygous) and 274 Hfe genotyped healthy subjects were studied. The following TcR chains were analyzed: Valpha2.3, Vbeta5.1, Vbeta5.2, Vbeta5.3, Vbeta6.7, Vbeta8, and Vbeta12 among the CD4(+) and CD8(+) populations. Lymphopenias and absence of expansions of the Vbeta5.2 and Vbeta12 chains in the CD8(+) pool were seen in controls heterozygous for the C282Y mutation. Expansions in the control group were seen within the CD8(+) pool and were rare/absent within the CD4(+) pool. TcR expansions were found more frequent in patients with iron overload related pathology than in patients without pathology. 9/16 of the patients with pathology have at least one expansion among the CD8(+) pool a number significantly higher compared with patients without pathology (1/16). These findings suggest that Hfe has an effect in the shaping of T-cell populations either directly, as indicated by the lymphopenia seen in the two chains in C282Y heterozygous without iron overload, or indirectly by contributing to iron overload pathology.

Quantitative assessment of the human TCRBV repertoire by competitive PCR

A novel quantitative protocol was developed for the measurement of the relative expression levels of the human TCRBV genes based on reverse transcription (RT) and subsequent competitive polymerase chain reaction (cPCR). Competitor DNA templates for the analysis of 24 different TCRBV families were generated by a simple and rapid one-step PCR procedure with a special PCR primer, which introduces a deletion in the constant region gene segment. A defined amount of TCRBV family-specific competitor DNA and the reverse transcribed cDNA of interest were amplified in the same tube with the same primer pair in a competitive way. The resulting fragments were separated on agarose gels and the densitometrical values were evaluated directly without the requirement for additional hybridization steps. For all of the 24 different TCRBV family-specific cPCRs equal amplification efficiencies were demonstrated by titration experiments for wild-type and competitor templates. For TCRBV repertoire studies, a short form of the cPCR assay was performed, requiring only one cPCR for quantitation of each TCRBV family. The exact initial amount of wild-type template in each cPCR was interpolated from TCRBV family-specific reference calibration curves. The RT-cPCR assay was applied for the quantitative assessment of the TCRBV repertoire of CD4+ and CD8+ T cell subsets in unstimulated PBMC and compared to flow cytometric analyses with a panel of monoclonal antibodies specific for TCRBV determinants. The RT-cPCR experiments revealed a differential expression of several BV families in either the CD4+ or the CD8+ fraction. The TCRBV family-specific cPCR assay presented here combines the simplicity and speed of conventional TCRBV family-specific PCR with the quantitative features of competitive PCR. TCRBV family-specific RT-cPCR has a broad application for all kinds of quantitative T cell repertoire studies and could be easily adapted for the usage with different BV-specific primer sets.

Assessment of T-cell receptor beta-chain diversity by heteroduplex analysis

The aim of this work was to search for a simple and alternative approach to the currently used methodologies for the analysis of T-cell receptor repertoire diversity. To this end we studied whether the heteroduplex analysis could be adapted to study the clonality of the T-cell receptor beta chain (TCRBV). We therefore analyzed, by sequencing, the molecular characteristics of the V-D-J junctions of numerous TCRBV chains from a variety of patients and from normal individuals, and compared the results with those obtained with the heteroduplex analysis. The latter procedure involves the amplification of the target TCRBV chains and the denaturation and renaturation of the amplified product to permit the random association of the distinct DNA strands encoding the different junctional regions. Whereas amplified material from polyclonal lymphoid cells migrates on a polyacrylamide gel as a "smear" of bands composed of different-sized polyclonal PCR fragments, the mismatched chains derived from oligoclonal populations migrate as discrete "heteroduplexes" and can be separated from the matched "homoduplex" obtained from homogeneous clonal cells. Our results provide evidence demonstrating that heteroduplex analysis can successfully be applied to the analysis of T-cell clonality in a variety of samples and can be complementary or substitute for the standard approach of TCR cloning and multiple sequencing of junctional regions. Thus, the procedure should facilitate the implementation of the analysis of TCR in diagnostic routine and should find applications in numerous physiologic and pathologic conditions.

V beta-specific activation of T cells by the HIV glycoprotein gp 160

Studies by several groups have suggested that HIV infection in vivo results in a V beta-specific alteration of the TCR repertoire and that this might play a role in the pathogenesis of AIDS. However, there is very little agreement as to which V beta segments are affected. In order to circumvent the confounding factors present in vivo we have examined the abilities of both a crude protein extract of HIV and purified gp160 to alter the V beta repertoire of normal T cells in vitro. We find that both a crude extract of HIV as well as gp160 specifically activate T cells expressing a common set of V beta segments (V beta 3, 12, 14, 15, and sometimes V beta 17 and 20) in individuals of disparate HLA type. This set of V beta segments is remarkably similar to those recognized by staphlococcal enterotoxin B and supports the hypothesis that bacterial superantigens produced by opportunistically acquired micro-organisms could have an exacerbating effect in AIDS.

Preferential usage of T-cell receptor V beta 17 by dengue virus-specific human T lymphocytes in a donor with immunity to dengue virus type 4

In order to better understand human T-cell responses to dengue viruses (DV), we analyzed T-cell receptor (TCR) V beta gene usage in DV-specific T lymphocytes. Peripheral blood T lymphocytes from a DV type 4 immune donor were stimulated in vitro with DV type 4 antigen, and TCR usage was examined by reverse transcriptase PCR. TCR V beta 17 was preferentially used (P = 0.020) among T cells stimulated by DV type 4 in bulk culture. Furthermore, 8 of 19 DV type 4-specific CD4+ T-cell clones established from the peripheral blood mononuclear cells expressed V beta 17 (P = 0.008). Preferential usage of TCR V alpha was not found among T cells expressing V beta 17. These results indicate that there is preferential usage of TCR V beta 17 among DV-specific T cells in this donor and suggest that T cells with certain TCRs may be important in immune responses to DV.

Nonrandom T-cell receptor J beta usage pattern in human CD4+ and CD8+ peripheral T cells

Association frequencies of TCR J beta gene segments with six V beta families (V beta 3, 6.1-3, 8, 9, 12, and 18) were analyzed in T-cell populations obtained from healthy blood donors. The six selected V beta families are located at various chromosomal positions relative to other recombinatorial elements (D beta, J beta, C beta). We report here that in CD4+ as well as CD8+ T-cell subsets, all 13 J beta gene segments were used in combination with all the V beta s tested and that no correlation between the genomic position of the individual V beta s and J beta gene segment usage was observed. J beta gene segment usage was found to be nonrandom in general, with J beta 2.7 and J beta 2.4 exhibiting highest and lowest frequency of utilization, respectively. J beta family 2 was used more frequently than J beta family 1 by the two T-cell subsets. Some individual J beta gene segments were skewed toward either CD4+ or CD8+ T cells. Thus, J beta 1.3 and J beta 1.6 were consistently biased toward expression in CD4+ T cells. In contrast, when combined with V beta 8 or V beta 9, J beta 2.1 results were skewed dramatically toward expression in CD8+ T cells. We also found 70 cases of expanded individual V beta/J beta associations in a total of 1092 investigated combinations, 62 of which were confined to the CD8+ T-cell populations. CD8+ T-cell populations are thus much more likely to contain TCR V beta/J beta-restricted expansions than CD4+ T cells.

Biased T cell receptor V gene usage in rheumatoid arthritis. Oligoclonal expansion of T cells expressing V alpha 2 genes in synovial fluid but not in peripheral blood

OBJECTIVE

To analyze the T cell receptor (TCR) variable (V) region gene usage in the rheumatoid joint.

METHODS

Monoclonal antibodies (MAb) were used to determine the prevalence of selected V elements on T cells in synovial fluid (SF) from rheumatoid arthritis (RA) patients and in peripheral blood (PB) from RA patients and normal controls. V alpha 2-positive PB and SF T cells from 1 patient were cloned by immediate limiting-dilution and analyzed by restriction mapping.

RESULTS

In 9 of 14 RA patients, SF was enriched in at least 1 of the selected V elements, compared with PB. TCR genes of the V alpha 2 family were the most frequently overrepresented in the SF (4 patients). The expanded V alpha 2-positive cells were oligoclonal in SF but heterogeneic in PB.

CONCLUSION

Our data showing biased and clonally restricted TCR elements in the rheumatoid joint indicate major histocompatibility complex-restricted antigen recognition, rather than a "superantigen," in the pathogenesis of RA.

T cell repertoire and autoimmune diseases

Self-reactivity and autoimmunity are processes related to the breakage of self-tolerance that can be distinguished by their different clinical outcome and are widely accepted cornerstones of immunology. The finding that several potentially autoaggressive cells contribute to the repertoire of healthy individuals has stimulated a great deal of experimental work aimed at understanding the mechanisms that prevent autoimmune pathology. In this review we will consider the basic principles, and our present knowledge of the rules that preside over the interplay of the immune system with self-components. One viewpoint stresses the importance of major histocompatibility complex (MHC) and non-MHC genes in determining genetic predisposition to develop autoimmune phenomena. At a different level there is a strong interest in understanding the mechanisms of processing and presentation of self antigens, especially during ontogeny. Another topic of major interest concerns the interaction between MHC genes and the T cell receptor (TcR) complex as well as the identification of TcR V genes that are preferentially expressed by autoimmune T cells. All of these aspects are evaluated in the context of tolerance based on deletion and anergy. Finally we will propose a general model of autoimmunity based on the most recent findings concerning the biological activity of exogenous superantigens.

The human T cell receptor V beta repertoire of normal peripheral blood lymphocytes before and after mitogen stimulation

Mitogen stimulation of T cells in vitro has been employed in the analysis of the T cell antigen receptor (TCR) repertoire and as a method of generating T cell lines and clones. It has been suspected for some time that mitogen stimulation may bias the repertoire. We have addressed this problem employing a semi-quantitative technique utilizing the polymerase chain reaction (PCR) and flow cytometry. Using this PCR method and a panel of primers to 22 V beta subgroups, the V beta repertoire of both unstimulated and phytohaemagglutinin (PHA)-stimulated peripheral T cells from eight healthy individuals was investigated. The samples were also analysed by flow cytometry using anti-V beta 2, V beta 5 and V beta 8 MoAbs. A significant increase in the expression of V beta 6, V beta 7.2 and V beta 10.1 was found in all eight samples of PHA-stimulated T cells compared with unstimulated T cells using the PCR method. In contrast, no differences were found between unstimulated and PHA-stimulated T cells by flow cytometry. These results question the validity of using mitogen-stimulated T cells to investigate TCR gene usage.

The human T-cell receptor beta-chain repertoire: longitudinal fluctuations and assessment in MHC matched populations

The influence of the environment and of the major histocompatibility complex (MHC) in shaping the human T-cell receptor beta-chain variable region (TCRBV) repertoire has not been systematically studied. Here, expression of TCRBV gene families was estimated by a sensitive polymerase chain reaction (PCR)-based method. Serial studies of peripheral blood, performed at 2-week intervals over a 3-month period, revealed that fluctuation in the expression of many TCRBV genes occurred in healthy individuals and in the absence of clinically evident infections. Fluctuation of TCRBV4, TCRBV5.2, TCRBV9, and TCRBV13.1 genes were present in all subjects. Additional TCRBV genes fluctuated in some but not in other individuals. Comparison of the TCRBV repertoire between these unrelated individuals indicated differences in the mean expression of TCRBV5.1, TCRBV9, TCRBV11, TCRBV15, TCRBV17, and TCRBV20 genes. For any TCRBV gene, intersubject differences were generally of a magnitude of twofold or less. Larger differences characterized the TCRBV repertoire of CD4 compared to CD8 cells. Some differences, for example over-representation of TCRBV2 and TCRBV5.1 on CD4, and TCRBV10, TCRBV14, and TCRBV16 on CD8 cells, were present in most subjects. Individuals homozygous for DR2- or DR3-bearing extended MHC haplotypes displayed similar individual variability of TCRBV expression. These data indicate that the circulating TCRBV repertoire in humans is both dynamic and diverse. Both environment and MHC effects contribute to the diversity of TCRBV expression.

Normal T cell receptor V beta usage in a primary immunodeficiency associated with HLA class II deficiency

The human T cell receptor was studied using an anchored-polymerase chain reaction (A-PCR) and hybridization with V beta-specific oligonucleotide probes, together with the few anti-V beta monoclonal antibodies (mAb) available. After confirming the semiquantitative and reproducible nature of the A-PCR technique, we assessed the complete V beta repertoire in sorted CD4+ and CD8+ lymphocyte populations from three normal donors. These experiments confirmed the absence of V beta-restricted deletions in human peripheral cells, in contrast to several mouse strains. This feature makes it difficult to study negative selection in man, given the apparent absence of an endogenous superantigen corresponding to the Mls system in the mouse. To investigate human V beta repertoire shaping, we studied V beta usage in CD4+ and CD8+ T cells from children with an inherited immunodeficiency characterized by defective expression of human leukocyte antigen class II molecules. An initial study using anti-V beta monoclonal antibodies failed to show significant abnormalities in V beta usage. Four patients analyzed using the A-PCR method all had a polyclonal V beta repertoire, suggesting normal positive selection and raising questions as to the importance of V beta major histocompatibility complex (MHC) interactions and the role of thymic MHC density in shaping the V beta repertoire.

T-cell receptor V-gene usage in neoplasms of the central nervous system. A comparative analysis in cultured tumor infiltrating and peripheral blood T cells

The use of tumor-infiltrating lymphocytes in the treatment of central nervous system (CNS) neoplasms has met with serious obstacles due to difficulty of culture and poor characterization. Since in other tumors the therapeutic effects of tumor-infiltrating lymphocytes have been shown to rely on T-cell receptor engagement, the authors addressed the question as to whether expression of T-cell receptor variable (V) domains in cultured tumor-infiltrating lymphocytes from CNS is different from that of autologous cultured peripheral blood mononuclear cells. Infiltrating lymphocytes from CNS neoplasms, including primary malignancies, metastatic cancers, and meningiomas, were cultured in the presence of interleukin-2 and anti-CD3 monoclonal antibodies (MoAb's) in order to obtain optimum growth of T cells. Autologous peripheral blood mononuclear cells from the same patients were similarly cultured. After 4 to 5 weeks of culture, 97.3% +/- 2.6% (mean +/- standard deviation) of the resulting cell populations were CD3-positive lymphocytes. The expression of T-cell receptor V domains was then studied by using a panel of 12 MoAb recognizing gene products from T-cell receptor V-alpha 2, V-beta 5, 6, 8, and 12, V-gamma 4 and 9 families, and from two subfamilies of V-delta 2. Remarkably, in over 70% of all paired measurements, percentages of T cells expressing discrete T-cell receptor V-gene products were found to be virtually identical in tumor- and peripheral blood-derived cultured cell populations, with differences never exceeding 1%. In contrast, a different expression of individual V-gene products, concerning both alpha/beta and gamma/delta T-cell receptors, could be detected between cultured tumor-infiltrating lymphocytes and autologous peripheral blood-derived T lymphocytes in seven of 12 patients. In two cases, significant differences between the two populations were also observed in the proliferative responses obtained upon stimulation with staphylococcal enterotoxins that trigger defined V-beta T-cell receptors. Altogether, these data suggest that the T-cell receptor repertoire of cultured tumor-infiltrating lymphocytes from CNS tumors, suitable for use in adoptive immunotherapies, differs from that of autologous cultured peripheral blood mononuclear cells.

Selection of T lymphocytes bearing limited T-cell receptor beta chains in the response to a human pathogen

Delayed-type hypersensitivity (DTH) is a classic measure of T-cell responsiveness to foreign antigen. To estimate the extent of the T-cell repertoire in the DTH response to a human pathogen, we measured T-cell receptor (TCR) beta-chain variable-region (V beta) gene usage in reversal reactions in leprosy. Reversal reactions represent naturally occurring DTH responses in leprosy, in which augmentation of T-cell responses to Mycobacterium leprae is concomitant with clearance of bacilli from lesions. T cells using the V beta 6-, V beta 12-, V beta 14-, and V beta 19-encoded TCRs were strikingly overrepresented in the lesions of patients as compared to blood and pre-DTH lesions from the same individuals. Furthermore, these data indicate a possible association between the predominant expression of a V beta gene segment in lesions and the major histocompatibility complex class II haplotype of the individual. V beta 6 was prominent in the lesions of four patients who were DR15, a marker of resistance in leprosy infection. Sequence analysis of V beta 6 TCRs showed frequent use of V beta 6.1 and J beta 2.7 gene segments and a conserved amino acid motif in the V-J junction in a reversal-reaction lesion, but not in blood from the same patient. The limited TCR repertoire expressed by the infiltrating T cells suggests that a limited set of antigens is recognized in the DTH response to a human pathogen. We suggest that the mechanism by which major histocompatibility complex haplotype influences DTH in this disease involves the presentation of specific peptides, with subsequent selection of specific TCRs followed by local oligoclonal expansion.

Effects of different culture protocols on the expression of discrete T-cell receptor variable regions in human tumour infiltrating lymphocytes

Therapeutic effects of tumour infiltrating lymphocytes (TIL) rely on T-cell receptor (TCR) engagement. In this work, the expression of five TCR alpha/beta variable (V) domains was quantitatively analysed by means of a panel of monoclonal antibodies (Mab) recognising gene products from TCR V alpha 2, V beta 5, V beta 6, V beta 8 and V beta 12 families in freshly isolated TIL and in autologous peripheral blood mononuclear cells (PBMC) from patients with neoplasms. In 3 out of 6 cases, differences in the expression of V beta 5, V beta 6, V beta 8 or V beta 12 could be detected. TIL populations were expanded by using recombinant human interleukin-2 (rhIL-2) alone or in addition to solid phase bound anti-CD3 Mab. Cultured TIL showed similar CD4/CD8 ratios and cytotoxic activity against autologous neoplastic target cells, regardless of the activation protocol. In 4 patients, the expression of TCR alpha/beta V gene products, as compared with TIL from freshly excised tumours, was found to be modified in cultured TIL, especially in cell populations activated with rhIL-2 only. These results indicate that TCR V gene usage in TIL may quantitatively differ from that in PBMC. TIL culture protocols using rhIL-2 alone or in combination with solid phase bound anti-CD3 may result in differential expression of discrete TCR V families.

Nearly identical T-cell receptor V-gene usage at birth in two cohorts of distinctly different ethnic origin: influence of environment in the final maturation in the adult

We have previously analysed the T-cell receptor (TCR) V-gene usage in peripheral blood T lymphocytes from a group of healthy Scandinavians, and described a biased representation (i.e. a statistically significant higher median representation) for some of the TCR V genes towards the CD4+ subpopulation. In a subsequent study the usage of the same V genes was analysed in single positive (CD4+ CD8- and CD4- CD8+) human thymocytes, and a similar type of skewness was noted. These observations might be explained by an influence of the specificity of the TCR of thymocytes on the maturation into the CD4+ or the CD8+ lineage. Such a model would assume an interaction between a common determinant on the major histocompatibility complex (MHC) class I or class II molecules, or with a peptide that is preferentially presented by either of the two molecules, and the TCR on the maturing thymocyte. To investigate the possible influence of a different genetic background and environment on skewed TCR V-gene representation, we have in this study analysed the TCR V-gene usage in peripheral blood and umbilical cord blood lymphocytes obtained from Asians, with a different ethnic and environmental background from our previous Scandinavian subjects. In the umbilical cord blood lymphocytes the TCR V-gene usage was close to identical between the two different ethnic groups in both CD4+ and CD8+ subpopulations. Analysing the peripheral blood lymphocyte (PBL) TCR V-gene usage, we found that three of the four monoclonal antibodies (MoAb) with a biased reactivity towards the CD4+ subpopulation in the Scandinavian group also showed a similar skewed reactivity in this study. Thus, the majority of the TCR V genes were used in a similar way. Some minor but definite discrepancies could be detected when comparing TCR V-gene usage in adult individuals from these two different ethnic groups. These differences could be inferred to be due to selective peripheral expansion through environmental pressure of T cells utilizing a specific V beta gene segment. We conclude that a striking preservation of biased TCR V-gene usage does exist in humans of distinctly different ethnic origin.

Expression and combinatorial diversity of germ line-encoded T cell receptor V genes in human peripheral blood T cells

The potential diversity of the T cell receptor (TcR) is defined by the combinational expression of variable segments and by mechanisms that insert or delete nucleotides at the junctional regions. The available repertoire is strongly influenced by negative and positive selection events. To study whether the diversity of the human T cell receptor of peripheral T cells is further restricted by the interaction between the TcR alpha and beta chains, we compared the level of transcription of different V alpha elements in human T cell blasts expressing either restricted or unrestricted sets of V beta genes. Our data establish that in some individuals, but not in others, the transcription of a given V alpha element is independent from the presence of particular V beta transcripts. Furthermore, our data also suggest that, in contrast to mouse, major TcR V gene deletions are absent in humans. Taken collectively, these results indicate that the diversity of the peripheral human TcR repertoire can benefit from the combinatorial expression of all the V elements present in the genome.

Analysis of amplified T cell receptor Vβ transcripts by a non-isotopic immunoassay

We have recently described a new colorimetric DNA enzyme immunoassay (DEIA) for detecting specific hybrids of complementary nucleic acids. This technology is based on an antibody that selectively recognizes double, but not single stranded DNA and therefore reveals the hybridization event independently from the DNA sequences. Most importantly, the test has an ELISA format and is very rapid and convenient for processing large numbers of samples. In the present report we have adapted this method to reveal the specificity of amplified T cell receptor V beta transcripts. V beta genes were amplified by polymerase chain reaction, using family specific primers and the specificity of the amplified products was determined by Southern blot and by DEIA. Our data demonstrate that DEIA had the same degree of sensitivity and specificity of conventional Southern hybridization. The possibility of analyzing amplified products with the simplicity of a conventional immunoassay should greatly facilitate the analysis of complex multigenic systems such as the T cell receptor and the immunoglobulin repertoire.