Analysis of TCR usage in human tumors: a new tool for assessing tumor-specific immune responses

Generation of V α13/β21+T cell specific target CML cells by TCR gene transfer

Adoptive immunotherapy with antigen-specific T cells can be effective for treating melanoma and chronic myeloid leukemia (CML). However, to obtain sufficient antigen-specific T cells for treatment, the T cells have to be cultured for several weeks in vitro, but in vitro T cell expansion is difficult to control. Alternatively, the transfer of T cell receptors (TCRs) with defined antigen specificity into recipient T cells may be a simple solution for generating antigen-specific T cells. The objective of this study was to identify CML-associated, antigen-specific TCR genes and generate CML-associated, antigen-specific T cells with T cell receptor (TCR) gene transfer. Our previous study has screened an oligoclonal Vβ21 with a different oligoclonal Vα partner in peripheral blood mononuclear cells (PBMCs) derived from patients with CML. In this study, oligoclonally expanded TCR α genes, which pair with TCR Vβ21, were cloned into the pIRES eukaryotic expression vector (TCR Vα-IRES-Vβ21). Next, two recombinant plasmids, TCR Vα13-IRES-Vβ21 and TCR Vα18-IRES-Vβ21, were successfully transferred into T cells, and the TCR gene-modified T cells acquired CML-specific cytotoxicity with the best cytotoxic effects for HLA-A11⁺ K562 cells observed for the TCR Vα13/Vβ21 gene redirected T cells. In summary, our data confirmed TCRVα13/Vβ21 as a CML-associated, antigen-specific TCR. This study provided new evidence that genetically engineered antigen-specific TCR may become a druggable approach for gene therapy of CML.

Diversity and divergence of the glioma-infiltrating T-cell receptor repertoire

Although immune signaling has emerged as a defining feature of the glioma microenvironment, how the underlying structure of the glioma-infiltrating T-cell population differs from that of the blood from which it originates has been difficult to measure directly in patients. High-throughput sequencing of T-cell receptor (TCR) repertoires (TCRseq) provides a population-wide statistical description of how T cells respond to disease. We have defined immunophenotypes of whole repertoires based on TCRseq of the α- and β-chains from glioma tissue, nonneoplastic brain tissue, and peripheral blood from patients. Using information theory, we partitioned the diversity of these TCR repertoires into that from the distribution of VJ cassette combinations and diversity due to VJ-independent factors, such as selection due to antigen binding. Tumor-infiltrating lymphocytes (TILs) possessed higher VJ-independent diversity than nonneoplastic tissue, stratifying patients according to tumor grade. We found that the VJ-independent components of tumor-associated repertoires diverge more from their corresponding peripheral repertoires than T-cell populations in nonneoplastic brain tissue, particularly for low-grade gliomas. Finally, we identified a "signature" set of TCRs whose use in peripheral blood is associated with patients exhibiting low TIL divergence and is depleted in patients with highly divergent TIL repertoires. This signature is detectable in peripheral blood, and therefore accessible noninvasively. We anticipate that these immunophenotypes will be foundational to monitoring and predicting response to antiglioma vaccines and immunotherapy.

Differences in TCR-Vβ repertoire and effector phenotype between tumor infiltrating lymphocytes and peripheral blood lymphocytes increase with age

Tumor infiltrating lymphocytes (TIL) reflect the host's anti-tumor immune response, and can be a valuable predictor of prognosis. However, many properties of TIL are not fully understood. In the present study, TCR-Vβ repertoires of cancer patients were primarily analyzed by flow cytometry. Abnormally expressed TCR-Vβ subfamilies were generally found in both TIL and peripheral blood lymphocytes (PBL) of each patient. Of note, increased patient age was associated with increasingly biased TCR-Vβ repertoire in TIL but not in PBL, and the dispersion degree of the differences of TCR-Vβ subfamilies between TIL and PBL correlated positively with age (P = 0.007). Utilizing immunoscope analysis, we identified the age-related reduction in TCR-Vβ diversity, but polyclonal pattern was predominant in significantly expanded TCR-Vβ subfamilies. In addition, we found that older patients possessed a decreased ratio of CD8+CD62L+ non-effector cells in TIL compared to PBL, implying age-related increase of CD8+CD62L- effector cells in TIL. The colocalization analysis of CD8 and CD3, however, suggested the suppressed activity of these effector cells in tumor microenvironment. These findings further elucidate the properties of TIL, showing an increasing difference between TIL and PBL with age, which may provide insight for the development of effective immunotherapies for cancer patients of different ages.

Leukemia Associated Clonal Expansion of TCR Vβ Subfamily T Cells

The analysis of the T cell receptor (TCR) Vbeta repertoire is one of the most sensitive methods to identify the clonal expansion T cells which respond to tumor associated antigens. Recently, studies have focused on clonally expanded T cells from patients or normal donors induced by leukemia associated antigens in vivo or in vitro. Understanding such clonality and restricted usage of TCR Vbeta repertoire of leukemia-associated expanded T cells may be useful for the design of new immuno-therapeutic strategy for leukemia.

Variation of tumor-infiltrating lymphocytes in human cancers: controversy on clinical significance

Tumors develop and progress under the influence of a microenvironment comprising a variety of immune cell subsets and their products. Recent studies have shown that tumor-infiltrating lymphocytes (TILs) are not randomly distributed, but organized to accumulate more or less densely in different regions within tumors, and interact with each other. Substantial evidence has suggested that not only CD8(+) and/or CD4(+) αβ T cells but also other lymphocyte subsets, including γδ T cells, B cells, NK cells, and NKT cells, infiltrate tumor tissues in variable quantities and play a key role in the regulation of antitumor immunity. In this article, we summarize available information regarding the diversity and composition of TILs, which may positively or negatively affect tumor growth and patient clinical outcomes. The clinical significance of TILs in human cancers remains unclear and is a subject of considerable controversy; largely due to the lack of functional data for TILs, as well as due to enormous variability of TILs in different tumors. A great deal more functional data about TILs needs to be obtained for individual tumors before TILs can be considered as a prognostic parameter in human cancers.

Restricted TRBV repertoire in CD4+ and CD8+ T-cell subsets from CML patients

T-cell immunodeficiency is a common feature in cancer patients, which may relate to initiation and development of tumor. In expanding our previous observations in this area, we studied the repertoire of T-cell receptor beta variable region (TRBV) and T-cell proliferative history in CD4+ and CD8+ T cells from chronic myeloid leukemia (CML) patients. The expression and clonality analysis were performed by reverse transcription-polymerase chain reaction (RT-PCR) and GeneScan technique in peripheral blood mononuclear cells (PBMCs), CD4+ and CD8+ subsets of T cells. Nineteen CML cases in chronic phase were selected for this study and 17 healthy individuals served as controls. Marked restriction of TRBV repertoire was observed in both CD4+ and CD8+ T cells from CML. In most CML samples, clonally expanded T cells were identified in CD4+ and CD8+ T cells, predominantly in TRBV19 and TRBV21 (5/19) subfamilies. In conclusion, the restricted expression of TRBV subfamilies indicates the T-cell immunodeficiency in CML patients; however, clonally expanded T cells suggest a specific immune response to leukemia associated antigens.

Longitudinal immune monitoring of patients receiving intratumoral injection of a MART-1 T-cell receptor-transduced cell line (C-Cure 709)

BACKGROUND AIMS

Adoptive transfer of tumor-specific lymphocytes is a promising strategy in the treatment of cancer. We conducted intratumoral administration of an allogeneic irradiated continuous T-cell line (C-Cure 709) expressing an HLA-A2-restricted MART-1-specific T-cell receptor (TCR) into HLA-A2(+) melanoma patients. The C-Cure 709 cell line is cytotoxic against MART-1(+) HLA-A2(+) melanoma cell lines and secretes several immune stimulatory cytokines upon stimulation.

METHODS

Anti-tumor immune responses against the commonly expressed tumor antigen (Ag) MART-1 were longitudinally analyzed in peripheral blood by fluorescence-activated cell sorting (FACS) before and after intratumoral injection of C-Cure 709.

RESULTS

No treatment-induced increase in Ag-specific T-cell frequencies was observed in peripheral blood, and the phenotype of MART-1-specific T cells was very stable during the treatment. Interestingly, despite a very stable frequency of MART-1-specific T cells over the course of treatment, clonotype mapping revealed that the response was in fact highly diverse and dynamic, with new clonotypes emerging during treatment. Only a few clonotypes were recurrently detected in consecutive samples. One MART-1-specific T-cell clone disappearing from peripheral blood was later detected in a metastatic lesion.

CONCLUSIONS

Sequence analyzes of the CDR3 region revealed conserved structural characteristics in the MART-1-specific TCR used by T-cell clones.

Antigen recognition and T-cell biology

Despite the wealth of information that has been acquired regarding the way T cells recognize their targets, we are left with far more questions than answers regarding how to manipulate the immune response to better treat cancer patients. Clearly, most patients have a broad repertoire of T cells capable of recognizing their tumor cells. Despite the presence of these tumor reactive T cells and our ability to increase their frequency though vaccination or adoptive transfer, patients still progress. From the T cell side, defects in T cell signaling may account for much of our failure to achieve significant numbers of objective clinical responses. In spite of these negatives, the horizon does remain bright for T cell based immune therapy of cancer. The periodic objective clinical response tells us that immune therapy can work. Now that we know that cancer patients have the capacity to mount immune responses against their tumors, current and future investigations with agents which alter T cell function combined with vaccination or adoptive T cell transfer may help tip the balance towards effective immune therapies.

Human T cell responses against melanoma

Many antigens recognized by autologous T lymphocytes have been identified on human melanoma. Melanoma patients usually mount a spontaneous T cell response against their tumor. But at some point, the responder T cells become ineffective, probably because of a local immunosuppressive process occurring at the tumor sites. Therapeutic vaccination of metastatic melanoma patients with these antigens is followed by tumor regressions only in a small minority of the patients. The T cell responses to the vaccines show correlation with the tumor regressions. The local immunosuppression may be the cause of the lack of vaccination effectiveness that is observed in most patients. In patients who do respond to the vaccine, the antivaccine T cells probably succeed in reversing focally this immunosuppression and trigger a broad activation of other antitumor T cells, which proceed to destroy the tumor.

T cell avidity and tumor recognition: implications and therapeutic strategies

In the last two decades, great advances have been made studying the immune response to human tumors. The identification of protein antigens from cancer cells and better techniques for eliciting antigen specific T cell responses in vitro and in vivo have led to improved understanding of tumor recognition by T cells. Yet, much remains to be learned about the intricate details of T cell – tumor cell interactions. Though the strength of interaction between T cell and target is thought to be a key factor influencing the T cell response, investigations of T cell avidity, T cell receptor (TCR) affinity for peptide-MHC complex, and the recognition of peptide on antigen presenting targets or tumor cells reveal complex relationships. Coincident with these investigations, therapeutic strategies have been developed to enhance tumor recognition using antigens with altered peptide structures and T cells modified by the introduction of new antigen binding receptor molecules. The profound effects of these strategies on T cell – tumor interactions and the clinical implications of these effects are of interest to both scientists and clinicians. In recent years, the focus of much of our work has been the avidity and effector characteristics of tumor reactive T cells. Here we review concepts and current results in the field, and the implications of therapeutic strategies using altered antigens and altered effector T cells.

Clonal dynamics of tumor-infiltrating lymphocytes

The presence of tumor-infiltrating lymphocytes (TIL) provides important evidence of anti-tumor immunity in vivo. However, TIL are usually not sufficient for inhibiting tumor growth. We explored the spatial and temporal aspects of clonal accumulation of TIL using RT-PCR/single-strand conformation polymorphism analysis. In CMS5 fibrosarcomas in BALB/c mice, accumulated T cell clones were specific in that dominant TIL were identical between distant tumors. Moreover, dominant TIL in the first tumor appeared consistently in the second tumor inoculated after formation of the first tumor. These results suggest that TIL show a certain level of specific tumor surveillance. When we characterized CD4(+) and CD8(+) TIL separately, CD8(+) TIL were highly concentrated and persistently localized at the tumor site, while most CD4(+) TIL clones were less concentrated and less persistent. A functional analysis showed that TIL had a certain degree of anti-tumor activity when CD4(+) and CD8(+) TIL were co-transferred. Co-transfer of CD4(+) and CD8(+) TIL exhibited equivalent anti-tumor activity, irrespective of tumor stage. However, the numbers of TIL did not increase after the early phase of tumor progression. These data suggest that TIL are specific to the tumor and potentially retain anti-tumor activity, although their accumulation in mice is impaired.

Clonal expanded TCR Vβ T cells in patients with APL

T-cell receptor Vss gene repertoire and clonality have been studied in patients with leukemia and solid tumors, by assaying the CDR3 size of TCR genes, using RT-PCR and genescan analysis. Few studies have studied leukemia-associated oligoclonal expanded T-cells in leukemia, therefore, the aim of this study was to investigate the distribution and clonal expansion of T-cell receptor, Vss subfamily T-cells in patients with acute promyelocytic leukemia (APL) with t(15;17). The CDR3 of TCR Vbeta24 subfamily genes were analyzed in peripheral blood mononuclear cells from 17 cases with PML-RARalpha+ APL using RT-PCR and genescan technique. Ten normal individuals served as controls. The results showed that the number of expressed Vss subfamilies (from 2 to 21 subfamilies) varied in different patients with APL. The most frequently expressed Vss subfamilies were Vbeta2 (64.7%), Vbeta15 (58.8%), Vbeta3 and Vbeta5 (47.1%), with a lower expression rate found in Vbeta11 and Vbeta20 (11.7%). Clonally expanded T-cells in the Vss subfamilies could be identified in patients with APL in all but two of the cases studied, predominantly in Vbeta10, Vbeta23, Vbeta3 and Vbeta21. In conclusion, skewed distribution and clonal expansion of TCR Vss subfamily T-cells could be found in patients with APL. The clonal expansion of T-cells were considered to be a specific anti-leukemic immune response by host T-cells activated by the leukemia-associated-antigen.

Heat shock protein induced TCR γδ gene rearrangements in patients with oral cancer

We analyzed the T cell receptor (TCR) gammadelta gene repertoire in peripheral blood and tumor compartment of oral cancer (OC) patients before and after stimulation with heat shock proteins (hsp), which are known ligands for gammadelta T cells. Clonal TCR gamma and delta gene rearrangements in lymphocytes from tumor compartment and peripheral blood were studied using TCR Vgamma and Vdelta gene primers in PCR followed by heteroduplex analysis. Vgamma gene segments derived from VgammaI or VgammaII gene families were most dominantly expressed in peripheral blood lymphocytes (PBL) as compared to tumor infiltrating lymphocytes (TIL) of OC patients. Of the rearranged TCR delta alleles Vdelta1-Jdelta1 and Vdelta2-Jdelta1 gene rearrangements were the most predominant in PBL and TIL of OC patients respectively. Stimulation of gammadelta T cells with hsp 60/70 demonstrated a selective clonal expansion of Vgamma9-Vdelta2 (VgammaII family) subset indicating that, this expanded population of cells could be responsible for eliciting an immune response against oral tumor cells.

Dynamic changes of specific T cell responses to melanoma correlate with IL-2 administration

Interleukin 2 (IL-2) is a promising immunotherapeutic agent for the treatment of metastatic melanoma and renal cell carcinoma. Systemic administration of high dose IL-2 produces objective responses in up to 25% of melanoma patients, and a low but significant proportion of these patients experience durable responses. Nevertheless, the cells and molecules responsible for induction of tumor regression over the course of IL-2 treatment remain unknown. New strategies in tumor immunotherapy have evolved over the past decade as a consequence of significant progress in the field, in particular with respect to the characterization of peptide epitopes derived from tumor associated antigens, and the role of antigen presenting cells in the initiation of cellular immune responses. Alongside with these factual as well as conceptual advances, new methods have been developed to monitor and characterize anti-tumor T cell responses in cancer patients. Application of these tools to dissect anti-tumor responses has demonstrated that various immune therapeutic approaches can induce powerful systemic anti-tumor cytotoxic T lymphocyte (CTL) responses. However, only limited efforts have been made to use present days tool to analyze anti-tumor immune responses in patients treated with IL-2 based immunotherapy. We have examined CTL responses against known tumor antigens in melanoma patients over the course of IL-2 based immunotherapy (electrochemotherapy). Surprisingly, anti-tumor CTL responses significantly declined upon initiation of therapy, but reappeared when IL-2 administration was paused. Molecular analyses of the clonotypic composition of responding T cells demonstrated that new clones emerged over the course of treatment, and that tumor-specific T cells that had left the peripheral blood could subsequently be detected at the tumor site. These data provide new insight into the biological actions of IL-2 and highlight the difficulties associated with the monitoring of anti-tumor immune responses. This underlines the importance of frequent sampling of blood and tumor biopsies to be analyzed with a combination of state of the art technologies in order to gain detailed information on the interactions between cancer cells and cells of the immune system.

T-cell clonotypes in cancer

Cells of the immune system spontaneously recognize autologous tumor cells and T cells are believed to be the main effector cells for the immune surveillance of cancer. Recent advances in our understanding of basic and tumor immunology together with methodological developments implies that tumor specific T cells can now be studied functionally, phenotypically as well as molecularly. T cells recognize peptide antigens in the context of MHC molecules through the clonally distributed T-cell receptor (TCR), thus, the clonal distribution of the TCR offers the means to detect and track specific T cells based upon detection of the unique TCR. In this review, we present and discuss available data on TCR utilization of tumor specific T cells in murine models as well as spontaneous and treatment induced anti-tumor T-cell responses in humans.

T-cell receptor repertoire in healthy Sardinian subjects

The T-cell receptor (TCR) Vbeta gene usage of CD4+ and CD8+ T-cell subpopulations was evaluated by flow cytometric analysis and by CDR3 spectratyping in healthy subjects belonging to Sardinian population, which is ethnically homogeneous and genetically distant from all other Italian and Caucasoid groups. As described in healthy Caucasian subjects, we found a nonrandom Vbeta gene usage and in some Vbeta families a significant skewed reactivity toward CD4+ T cells. Moreover, different subjects showed expansions in some Vbeta subfamilies, mainly in the CD8+ T cells. By CDR3 spectratyping analysis we found a significantly higher degree of skewness in the TCR Vbeta repertoire of CD8+ than in that of CD4+ T cells. The similarity found in the TCR Vbeta gene usage between the population examined and other Caucasoid groups suggest that the shape of the TCR repertoire is more influenced by rearrangement processes than ethnic background. However, genetic polymorphisms may condition the expression levels of some Vbetas, determining the variability of the TCR repertoire between different populations. Finally, the profound perturbations evidenced in the CD8+ T cell subpopulation could be related to a different response to the antigenic stimulation between CD8+ and CD4+ T lymphocytes.

T-cell immune responses in the brain and their relevance for cerebral malignancies

In order that cellular immune responses afford protection without risk to sensitive normal tissue, they must be adapted to individual tissues of the body. Nowhere is this more critical than for the brain, where various passive and active mechanisms maintain a state of immune privilege that can limit high magnitude immune responses. Nevertheless, it is now clear that immune responses are induced to antigens in the brain, including those expressed by cerebral malignancies. We discuss hypotheses of how this can occur, although details such as which antigen presenting cells are involved remain to be clarified. Antitumor responses induced spontaneously are insufficient to eradicate malignant astrocytomas; many studies suggest that this can be explained by a combination of low level immune response induction and tumor mediated immunosuppression. A clinical objective currently pursued is to use immunotherapy to ameliorate antitumour immunity. This will necessitate a high level immune response to ensure sufficient effector cells reach the tumor bed, focused cytotoxicity to eradicate malignant cells with little collateral damage to critical normal cells, and minimal inflammation. To achieve these aims, priority should be given to identifying more target antigens in astrocytoma and defining those cells present in the brain parenchyma that are essential to maintain antitumour effector function without exacerbating inflammation. If we are armed with better understanding of immune interactions with brain tumor cells, we can realistically envisage that immunotherapy will one day offer hope to patients with currently untreatable neoplastic diseases of the CNS.

Immunology and immunotherapy of colorectal cancer

This review critically discusses data on immunology of colorectal cancer, starting from pathology and molecular biology, and then considering the molecular characterisation of colon cancer antigens and the clinical trials of immunotherapy. A careful evaluation of histopathological studies on intra-epithelial infiltration by T cells in primary tumours, together with the analysis of HLA expression by colorectal cancer cells, suggest that anti-tumour T cell immune responses may take place in vivo in those patients, influencing prognosis and shaping the tumour immunological profile. Moreover, the molecular characterisation of tumour antigens expressed by colorectal carcinomas, together with improved understanding of mechanisms of the immune response and more sensitive methods for the in vivo detection of T cell responses, are now allowing researchers to design new and more effective vaccination protocols, with encouraging preliminary results. By drawing together the experimental evidence from different research fields, this review provides support for the concept that colorectal carcinoma is immunogenic and may reasonably be considered as a target for immunotherapy, and attempts to address critical issues and envisage future developments in this challenging research field.

Leukemia-associated monoclonal and oligoclonal TCR-BV use in patients with B-cell chronic lymphocytic leukemia

T-cell receptor-B-variable (TCR-BV) gene usage and the CDR3 size distribution pattern were analyzed by reverse transcription-polymerase chain reaction (RT-PCR) in patients with B-cell chronic lymphocytic leukemia (B-CLL) to assess the T-cell repertoire. The use of TCR-BV families in CD4 and CD8 T cells stimulated with autologous activated leukemic cells was compared with that of freshly obtained blood T cells. Overexpression of individual TCR-BV families was found in freshly isolated CD4 and CD8 T cells. Polyclonal, oligoclonal, and monoclonal TCR-CDR3 patterns were seen within such overexpressed native CD4 and CD8 TCR-BV families. In nonoverexpressed TCR-BV families, monoclonal and oligoclonal populations were noted only within the CD8 subset. After in vitro stimulation of T cells with autologous leukemic B cells, analyses of the CDR3 length patterns showed that in expanded TCR-BV populations, polyclonal patterns frequently shifted toward a monoclonal/oligoclonal profile, whereas largely monoclonal patterns in native overexpressed TCR-BV subsets remained monoclonal. Seventy-five percent of CD8 expansions found in freshly obtained CD8 T cells further expanded on in vitro stimulation with autologous leukemic B cells. This suggests a memory status of such cells. In contrast, the unusually high frequency of CD4 T-cell expansions found in freshly isolated peripheral blood cells did not correlate positively to in vitro stimulation as only 1 of 9 expansions continued to expand. Our data suggest that leukemia cell-specific memory CD4 and CD8 T cells are present in vivo of patients with CLL and that several leukemia cell-associated antigens/epitopes are recognized by the patients' immune system, indicating that whole leukemia cells might be of preference for vaccine development.

T-cell receptor V? gene usage by T cells reactive with the tumor-rejection antigen SART-1 in oral squamous cell carcinoma

We recently described that the SART-1(690-698) peptide could induce HLA-A24-restricted cytotoxic T lymphocytes (CTLs), which recognize the SART-1(259) (+) tumor cells from peripheral blood mononuclear cells (PBMCs) of HLA-A24(+) cancer patients. In our study, in 5 of 14 HLA-A24(+) patients with oral squamous cell carcinomas (SCCs), CTLs could be induced with the SART-1(690-698) peptide from the PBMCs. In 2 of the patients from whom the highest CTL activities were induced, the T-cell receptor (TCR) Vbeta repertoire expressed by the SART-1(690-698)-specific CTLs was found to be restricted and multiple Vbeta families were predominantly expressed in each patient. Although the predominant Vbeta families were different between the 2 patients, Vbeta7 was highly and commonly predominant. The same predominant Vbeta families were also detected in the tumor-infiltrating lymphocytes (TILs) from each patient, and each Vbeta family contained one or more unique T-cell clonotypes. The unique T-cell clonotypes were found to be common between the TILs and SART-1(690-698)-specific CTLs from each patient, and especially 2 T-cell clonotypes with Vbeta7 were identical even in the 2 patients. One of the 2 T-cell clonotypes with Vbeta7 was detected in the TILs from 11 of 14 HLA-A24(+) patients and another was found in those from 8 of HLA-A24(+) patients, while none of 10 HLA-A24(-) patients demonstrated both T-cell clonotypes. These results strongly suggest that the T-cell clonotypes with Vbeta7 are major TCR Vbeta genes expressed by SART-1(690-698)-specific CTLs. Furthermore, autologous tumor cells from one of the HLA-A24(+) patients stimulated the PBMCs and regional lymph node cells (LNCs) to expand the same T-cell clonotypes as those in the SART-1(690-698)-specific CTLs. These results strongly suggest that the SART-1(690-698)-specific CTLs clearly accumulate in vivo, especially in the TILs, as a consequence of in situ antigenic stimulation by autologous tumor cells. The identification of the unique TCR Vbeta genes used by SART-1(259)-specific CTLs should help to improve the diagnosis of the specific immune response in patients with SART-1(259) (+) cancers, especially during anticancer immunotherapy.

HER-2/neu-derived peptide epitopes are also recognized by cytotoxic CD3(+)CD56(+) (natural killer T) lymphocytes

The human HER-2/neu gene encodes a 185 kDa transmembrane glycoprotein recognized by MHC class I-restricted CTLs. Here, we report that HER-2/neu peptide CTL epitopes can also be recognized by cytotoxic NK-T lymphocytes. Unfractionated peptides derived from HLA-A2(+), HER-2/neu(+) tumor cells acid cell extract (ACE), collected from patients with metastatic ovarian cancer, were used as antigen to generate in vitro cytotoxic effectors. ACE was able to elicit from cancer patients' PBMCs both alphabetaTCR(+)CD3(+)CD56(-) and alphaTCR(+)CD3(+)CD56(+) (NK-T) CTLs that lysed ACE-sensitized T2 cells in an HLA-A2-restricted manner. The same CTL lines also recognized T2 cells pulsed with HER-2/neu-derived CTL peptide epitopes, a HER-2/neu-transfected HLA-A2(+) cell line and autologous tumor cells. alphaTCR(+)CD3(+)CD56(+) CTL lines also exhibited NK-like cytotoxicity against autologous tumor cells. CTL clones were isolated from alphaTCR(+)CD3(+)CD56(+) bulk cultures displaying both MHC- and non-MHC-restricted cytotoxicity, thus confirming the dual cytolytic function of such cells. Our data demonstrate that ACE from metastatic ovarian tumors can be used as multiepitope vaccines for generating in vitro, besides classical CTLs, NK-T cells exerting efficient MHC- and non-MHC-restricted cytotoxicity against autologous tumor targets. Such NK-T cells expressing dual cytotoxic activity may prove advantageous in cancer immunotherapy.

Improved assessment of T-cell receptor (TCR) VB repertoire in clinical specimens: combination of TCR-CDR3 spectratyping with flow cytometry-based TCR VB frequency analysis

Antigen-specific T-cell responses may be described by combining three categories: (i) the specificity and effector functions of a T-cell population, (ii) the quantity of T-cell responses (i.e., the number of responding T cells within the CD4/CD8 population), and (iii) the "quality" of T cells (defined by the T-cell receptor [TCR] structure). Several methods to measure T-cell responses are now available including evaluation of T-cell precursors using limiting dilution, the enzyme-linked immunospot assay, ex vivo TCR variable (v)-segment analysis determined by flow cytometry, and TCR-CDR3 length analysis (spectratyping), as well as identification of peptide-specific T cells using major histocompatibility complex (MHC) class I tetramers containing appropriate peptides. Until now, only a limited set of MHC-peptide complexes have been available as tetramer complexes. We demonstrate that CD8(+) or CD4(+) T cells in patients with cancer can be molecularly defined using a combination of spectratyping (TCR structure and "molecular composition") plus the implementation of an antibody panel directed against 21 individual VB TCR chains ("quantity" of T-cell families). This approach is instrumental in defining and comparing the magnitudes of CD4(+) or CD8(+) T-cell responses over time in individual patients, in comparing the TCR VA and VB repertoire in different anatomic compartments, and in comparing the TCR VA-VB diversity with that in normal healthy controls. This method provides the means of objectively defining and comparing the TCR repertoire in patients undergoing vaccination protocols and underlines the necessity to calibrate the TCR-CDR3 analysis with a qualitative assessment of individual TCR VB families.

Comparative assessment of TCRBV diversity in T lymphocytes present in blood, metastatic lesions, and DTH sites of two melanoma patients vaccinated with an IL-7 gene-modified autologous tumor cell vaccine

A phase I clinical trial using autologous, IL-7 gene-modified tumor cells in patients with disseminated melanoma has been recently completed. Although no major clinical responses were observed, increased antitumor cytotoxicity was measured in postvaccine peripheral blood lymphocytes in a subset of treated patients. To analyze the in situ immune response, the T cell receptor beta-chain variable region (BV) repertoire of T cells infiltrating postvaccine lesions was studied in two patients, and compared with that of T cells present in prevaccine ones, in peripheral blood lymphocytes, and, in one patient, in delayed type hypersensitivity (DTH) sites of autologous melanoma inoculum. A relative expansion of T cells expressing few BVs was observed in all postvaccine metastases, and their intratumoral presence was confirmed by immunohistochemistry. Length pattern analysis of the complementarity determining region 3 (CDR3) indicated that the repertoire of T cells expressing some of these BVs was heterogeneous. At difference, CDR3, beta-chain joining region usage, and sequence analysis enabled us to demonstrate, within a T-cell subpopulation commonly expanded at DTH sites and at the postvaccine lesion of patient 1, that both DTH sites contained identical dominant T-cell clonotypes. One of them was also expressed at increased relative frequency in the postvaccine lesion compared to prevaccine specimens. These results provide evidence for immunological changes, including in situ clonally expanded T cells, in metastases of patients vaccinated with IL-7 gene-transduced cells.

Human autologous monocytes and monocyte-derived macrophages in co-culture with carcinoma F-spheroids secrete IL-6 by a non-CD14-dependent pathway

The secretion of interleukin (IL)-1 beta, IL-6 and tumour necrosis factor (TNF)-alpha were compared when freshly isolated autologous monocytes or monocytederived macrophages (MDMs) were co-cultured in vitro with autologous fragment (F)-spheroids established from a series of head and neck squamous cell carcinoma (HNSCC) patients. F-spheroids were generated from the malignant tumour (M-spheroids) or from benign mucosa (B-spheroids) from which the tumour originated control. If monocytes maturated towards MDMs before co-culture, the IL-6 secretion declined dependent on the extent of the MDM maturation by both M- and B-spheroid stimulation. When MDMs maturated in continuous co-culture, a steady-state secretion of IL-6 continued for several days but diminished when the culture medium was changed every 24 h. No co-culture-induced IL-1 beta or TNF-alpha was determined. Both the cytokine secretion and the mRNA gene expression revealed a different monocyte/MDM activation when co-culture and lipopolysaccharide (LPS)-stimulation were compared. Addition of anti-CD14 (10 microg/ml) decreased monocyte LPS-stimulated, but increased monocyte co-culture stimulated IL-6 secretion. In conclusion, M- and B-spheroids similarly stimulated monocytes and to a lesser extent MDMs. MDMs that maturated with F-spheroids present, retained responsiveness at the monocyte level. Co-culture-induced monocyte stimulation, as measured by IL-6 secretion, was not dependent on activation via the CD14 molecule.

Abnormal T-cell repertoire is consistent with immune process underlying the pathogenesis of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal disorder of the hematopoietic stem cell (HSC). Somatic mutations in thePIG-A gene result in the deficiency of several glycosylphosphatidylinositol-linked proteins from the surface of blood cells. This explains intravascular hemolysis but does not explain the mechanism of bone marrow failure that is almost invariably seen in PNH. In view of the close relationship between PNH and idiopathic aplastic anemia (IAA), it has been suggested that the 2 disorders might have a similar cellular pathogenesis, namely, that autoreactive T-cell clones are targeting HSCs. In this paper, we searched for abnormally expanded T-cell clones by size analysis of the complementarity-determining region 3 (CDR3) in the beta variable chain (BV) messenger RNA (mRNA) of the T-cell receptor (TCR) in 19 patients with PNH, in 7 multitransfused patients with hemoglobinopathy. and in 11 age-matched healthy individuals. We found a significantly higher degree of skewness in the TCR BV repertoire of patients with PNH, compared with controls (R2 values 0.82 vs 0.91,P < .001). The mean frequency of skewed families per individual was increased by more than 2-fold in patients with PNH, compared with controls (28% ± 19.6% vs 11.4% ± 6%,P = .002). In addition, several TCR BV families were significantly more frequently skewed in patients with PNH than in controls. These findings provide experimental support for the concept that PNH, like IAA, has an immune pathogenesis. In addition, the identification of expanded T-cell clones by CDR3 size analysis will help to investigate the effect of HSC-specific T cells on normal and PNH HSCs.

Abnormal T-cell repertoire is consistent with immune process underlying the pathogenesis of paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal disorder of the hematopoietic stem cell (HSC). Somatic mutations in thePIG-A gene result in the deficiency of several glycosylphosphatidylinositol-linked proteins from the surface of blood cells. This explains intravascular hemolysis but does not explain the mechanism of bone marrow failure that is almost invariably seen in PNH. In view of the close relationship between PNH and idiopathic aplastic anemia (IAA), it has been suggested that the 2 disorders might have a similar cellular pathogenesis, namely, that autoreactive T-cell clones are targeting HSCs. In this paper, we searched for abnormally expanded T-cell clones by size analysis of the complementarity-determining region 3 (CDR3) in the beta variable chain (BV) messenger RNA (mRNA) of the T-cell receptor (TCR) in 19 patients with PNH, in 7 multitransfused patients with hemoglobinopathy. and in 11 age-matched healthy individuals. We found a significantly higher degree of skewness in the TCR BV repertoire of patients with PNH, compared with controls (R2 values 0.82 vs 0.91,P < .001). The mean frequency of skewed families per individual was increased by more than 2-fold in patients with PNH, compared with controls (28% ± 19.6% vs 11.4% ± 6%,P = .002). In addition, several TCR BV families were significantly more frequently skewed in patients with PNH than in controls. These findings provide experimental support for the concept that PNH, like IAA, has an immune pathogenesis. In addition, the identification of expanded T-cell clones by CDR3 size analysis will help to investigate the effect of HSC-specific T cells on normal and PNH HSCs.

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.

TCR v(beta) usage and clonality of T cells isolated from progressing and rejected tumor sites before and after in vitro culture

A gelatin sponge model of concomitant tumor immunity was employed in order to examine the clonality of T cells associated with progressing and rejected tumor sites. Here we show that freshly isolated T cells bearing TCR V(beta)1, CDR3 RPGTGN, J(beta)1.1 and TCR V(beta)8, CDR3 GD, J(beta)1.6 predominated progressing and rejected tumor sites. Despite the similarity in T cell populations, the T cells from rejected tumor sites were capable of killing the autologous tumor cells, whereas T cells from progressing tumor sites were not able to do so. The differing cytolytic ability could not be attributed to a difference in TCR zeta chain protein expression levels between both T cell populations. After a 5 day mixed lymphocyte tumor culture the T cells from the progressing tumor site were capable of killing autologous tumor cells, which suggested changes took place within the cell population during in vitro culture. Further TCR analysis revealed T cells bearing TCR V(beta)1, CDR3 RPGTGN, J(beta)1.1 and TCR V(beta)8, CDR3 GD, J(beta)1.6 were not expanded following the in vitro culture. These data suggest that the lack of cytotoxicity of freshly isolated tumor-infiltrating lymphocytes (TIL) was not due to abnormal TCR zeta chain expression or major differences in the TCR V(beta) usage. Additionally, the gain of TIL effector function did not correlate with an expansion of the TCR bearing T cells found to predominate the in vivo response. These data suggest that the predominant TCR V(beta) used by lymphocytes infiltrating regressing or rejected tumors may not represent the tumor reactive T cells that grow in culture or respond to the autologous tumor in vitro.

Differential Loss of T Cell Signaling Molecules in Metastatic Melanoma Patients’ T Lymphocyte Subsets Expressing Distinct TCR Variable Regions

In this study we tested the hypothesis that loss of T cell signaling molecules in metastatic melanoma patients’ T cells may affect differently T cell subsets characterized by distinct TCR variable regions. By a two-color immunofluorescence technique, expression of ζ-chain, lck, and ZAP-70 was evaluated in CD3+ T cells and in three representative T cell subsets expressing TCRAV2, TCRBV2, or TCRBV18. Partial loss of lck and ZAP-70 was found in CD3+ T cells from PBL of most melanoma patients, but not of healthy donors. The extent of ζ-chain, lck, and ZAP-70 loss depended on the TCRV region expressed by the T cells, and this association was maintained or increased during progression of disease. Coculture of patients’ or donors’ T cell with melanoma cells, or with their supernatants, but not with normal fibroblasts or their supernatants, down-modulated expression of ζ-chain, lck, and ZAP-70 in a TCRV region-dependent way. Immunodepletion of soluble HLA class I molecules present in tumor supernatants, but not of soluble ICAM-1, blocked the suppressive effect on T cell signaling molecule expression. T cell activation with mAbs to a single TCRV region and to CD28 led to significant and TCRV region-specific re-induction of ζ-chain expression. These findings indicate that extent of TCR signaling molecules loss in T lymphocytes from metastatic melanoma patients depends on the TCRV region and suggest that tumor-derived HLA class I molecules may contribute to induce such alterations.

Accumulation of identical T cells in melanoma and vitiligo-like leukoderma

The cloning of genes encoding melanoma antigens has opened new possibilities for the treatment of patients with cancer; however, most tumor rejection antigens recognized by tumor infiltrating lymphocytes are the products of genes that are also expressed by normal melanocytes. Hence, a large set of antigenic determinants of the self have not induced self-tolerance and these peptide determinants furnish target structures for immune responses directed against tumors. The notion that the immunotherapeutic targets involved in cancer regression comprise normal differentiation antigens is stressed by the association between vitiligo-like leukoderma, due to destruction of normal melanocytes, and melanoma regression, due to destruction of cancer cells. Nevertheless, this is the first report to demonstrate by means of a new technique based on reverse transcription polymerase chain reaction and denaturing gradient gel electrophoresis, the presence of clonally expanded T cells with identical BV regions in areas of destruction of both normal and neoplastic cells.

In vivo selective expansion of a tumour-specific cytotoxic T-cell clone derived from peripheral blood of a melanoma patient after vaccination with gene-modified autologous tumour cells

Melanoma-specific cytotoxic T lymphocytes (CTL) can be generated from peripheral blood lymphocytes (PBL) by mixed lymphocyte-tumour cell cultures. Analysis of CTL precursor frequencies in peripheral blood of melanoma patients is generally used for immunomonitoring purposes to evaluate vaccination efficacy. At present, it is unclear whether PBL-derived CTL generated in vitro are indicative of an anti-tumour immune response in vivo. Three tumour-specific human leucocyte antigen (HLA)-B/C-restricted CTL clones were derived from peripheral blood of a melanoma patient immunized with interleukin-7 (IL-7) gene-modified tumour cells. CTL clones differing in their T-cell receptor-gamma (TCRgamma) rearrangement produced interferon-gamma, IL-4 and/or IL-10. On the basis of their unique TCRgamma gene rearrangements clone-specific primers were generated for detection of clone-specific DNA by polymerase chain reaction. One CTL clone (E5) of the three was found to be selectively expanded in one of seven metastases obtained at autopsy, as determined by Southern blot hybridization. However, the presence of E5 in only one of seven metastases at death indicates that the in vivo accumulation of the specific CTL clone was not sufficient to contain tumour progression. Nevertheless, our data support the proposition that analysis of anti-tumour activity of PBL-derived CTLs may reflect an anti-tumour immune response in vivo.

An expanded peripheral T cell population to a cytotoxic T lymphocyte (CTL)-defined, melanocyte-specific antigen in metastatic melanoma patients impacts on generation of peptide-specific CTLs but does not overcome tumor escape from immune surveillance in metastatic lesions

It is not known if immune response to T cell-defined human histocompatibility leukocyte antigen (HLA) class I-restricted melanoma antigens leads to an expanded peripheral pool of T cells in all patients, affects cytotoxic T lymphocyte (CTL) generation, and correlates with anti-tumor response in metastatic lesions. To this end, a limiting dilution analysis technique was developed that allowed us to evaluate the same frequency of peptide-specific T cells as by staining T cells with HLA-peptide tetrameric complexes. In four out of nine patients, Melan-A/Mart-1(27-35)-specific CTL precursors (CTLp) were >/=1/2,000 peripheral blood lymphocytes and found mostly or only in the CD45RO(+) memory T cell subset. In the remaining five patients, a low (<1/40,000) peptide-specific CTLp frequency was measured, and the precursors were only in the CD45RA(+) naive T cell subset. Evaluation of CTL effector frequency after bulk culture indicated that peptide-specific CTLs could be activated in all patients by using professional antigen-presenting cells as dendritic cells, but CTLp frequency determined the kinetics of generation of specificity and the final number of effectors as evaluated by both limiting dilution analysis and staining with HLA-A*0201-Melan-A/Mart-1 tetrameric complexes. Immunohistochemical analysis of 26 neoplastic lesions from the nine patients indicated absence of tumor regression in most instances, even in patients with an expanded peripheral T cell pool to Melan-A/Mart-1 and whose neoplastic lesions contained a high frequency of tetramer-positive Melan-A/Mart-1-specific T cells. Furthermore, frequent lack of a "brisk" or "nonbrisk" CD3(+)CD8(+) T cell infiltrate or reduced/absent Melan-A/Mart-1 expression in several lesions and lack of HLA class I antigens were found in some instances. Thus, expansion of peripheral immune repertoire to Melan-A/Mart-1 takes place in some metastatic patients and leads to enhanced CTL induction after antigen-presenting cell-mediated selection, but, in most metastatic lesions, it does not overcome tumor escape from immune surveillance.

Oligoclonal expansions of T-cell repertoire in gastric mucosa associated lymphoid tissue type B-cell lymphoma and adjacent gastritis

Local stimulation by Helicobacter pylori (HP), autoantigen, and a concurrent T-cell-mediated stimulation of B cells are believed to play an important role in gastric mucosa-associated lymphoid tissue (MALT) type B cell lymphomagenesis. Many autoimmune diseases have shown to lead to a skewed T-cell repertoire with autoantigen specific expansions and deletions. Characterization of lymphoma and gastritis areas of seven gastrectomy specimens using a T-cell receptor beta variable chain (TCR betaV) family-specific reverse transcriptase (RT)-polymerase chain reaction (PCR) assay and fluorescence-activated cell sorter (FACS) analysis revealed a local chronic and acute activation of T cells in lymphoma and an oligoclonal T-cell repertoire in gastritis and in lymphoma, partially sharing the same clones. Local activation and a partial identity suggest that an antigenic challenge caused by a common local pathogen may still continue to take place in MALT type lymphoma as in gastritis, consistent with the view that gastritis may be a precursor lesion of MALT type lymphoma. Expansions that were found only in one of the compartments suggest that also an immune hyperstimulation may contribute to the T-cell repertoire, possibly because of certain tissue antigens. Deletions of TCR betaV families found only in gastritis underline the view that autoantigen may play an important role in its pathogenesis.

Oligoclonal TCRBV Gene Usage in B-Cell Chronic Lymphocytic Leukemia: Major Perturbations Are Preferentially Seen Within the CD4 T-Cell Subset

TCRBV (T-cell receptor B variable) gene usage and CDR3 size distribution were analyzed using reverse transcription polymerase chain reaction (RT-PCR) to assess the T-cell repertoire of 10 patients with B-cell chronic lymphocytic leukemia (B-CLL) and in nine age-matched healthy control donors. When the usage of each TCRBV gene within the CD8+ T cells of the patients was compared with that of the controls, no statistically significant difference was noted except for BV 6S1-3. In contrast, within the CD4+ T cells of the CLL patients, a statistically significant overexpression for four BV families (2, 3, 5S1, 6S1-3) was seen while an underrepresentation was noted for five BV families (10, 11, 15, 16, 19). Based on the criterion that a value of any BV higher than the mean + 3 standard deviation (SD) of healthy controls indicated an overexpression, individual patients were shown to overexpress several TCRBV genes compared with the controls. Analyses of the CDR3 length polymorphism showed a significantly higher degree of restriction within CD4+ and CD8+ T cells of the patients, as compared with the corresponding control T-cell population. There was a significant difference in the CDR3 size distribution pattern with a more polymorphic CDR3 length pattern in the age-matched controls as compared with CLL patients, suggesting different mechanisms driving the T cells towards a clonal/oligoclonal TCRBV usage in patients and controls, respectively. The results show major perturbations of T cells in CLL patients, more frequently seen in the CD4+ T-cell subset, indicating that nonmalignant CD4+ T cells may be involved in the pathogenesis of CLL, but also CD8+ T cells.

Astrocytoma infiltrating lymphocytes include major T cell clonal expansions confined to the CD8 subset

Anaplastic astrocytoma and glioblastoma are frequent and malignant brain tumors that are infiltrated by T lymphocytes. Whether these cells result from non-specific inflammation following blood-brain barrier disruption or an antigen-driven specific immune response is unknown. In this study, an in-depth characterization of TCR diversity in tumor and blood RNA biopsies was performed in a series of 16 patients with malignant astrocytoma. Whilst there was no obvious restriction of the AV and BV gene segment usage, complementarity-determining region 3 size analysis and sequencing of amplified TCR transcripts revealed multiple T cell oligoclonal expansions in all astrocytomas analyzed. Unique T cell clones were present in different adjacent areas of a given tumor, but never detected in the blood. Quantification of the number of TCR clonal transcripts per microg of tumor RNA indicated that certain T cell clonal expansions may represent at least 300 cells/10(6) tumor cells. Furthermore, we demonstrated that the in vivo expanded clones were almost exclusively confined to the CD8(+) subset. Overall, these data suggest that spontaneous antigen-driven immune responses may be elicited against human astrocytoma despite the immunosuppressive microenvironment generated by the brain and the tumor itself. However, the ultimate failure of the immune system to control tumor growth could be the consequence of a deficient CD4 T(h) component of the response. This observation could have important consequences for the development of immunotherapies for astrocytoma patients.

Analysis of T-cell-receptor beta-chain-gene usage in peripheral-blood and tumor-infiltrating lymphocytes from human non-small-cell lung carcinomas

Non-small-cell lung cancers (NSCLC) are often infiltrated by T lymphocytes. It is postulated that the presence of tumor-infiltrating lymphocytes (TIL) reflects a local host immune response against autologous tumors. To identify the nature of NSCLC TIL, we have characterized the molecular structure of the TCRbeta chain expressed by infiltrating T cells and paired PBL from 9 untreated patients (4 LLC, 3 ADC and 2 SCC). For this purpose, we have used a high-resolution PCR-based method that determines CDR3 size patterns in TCRVbeta sub-families in fresh tumors and their corresponding autologous PBL samples. Oligoclonality in T-cell populations was observed in 3 (Hor, Bla and Pub) out of 9 tumor biopsies analyzed. In contrast, the TCR repertoire of the 6 following patients as well as of all the autologous PBL was diverse, with virtually all Vbeta specificities expressed. Among the 3 tumors with dominant T-cell clonotypes, relative expansion of some T-cell sub-populations was observed. One patient (Hor) with significant TCRVbeta21 expansion in tumor compared with autologous PBL, showed over-expression of a particular TCRVbeta chain with unique Vbeta21-D-Jbeta2.7 junctional region not detected in autologous PBL. TCRVbeta21/Jbeta2.7 expansion was also observed in IL-2-stimulated TIL cell lines and was confirmed by sequencing analysis of the V-D-J junctional region. These results strengthen the view that local antigen-driven selection may occur, and support the hypothesis that anti-tumor immune response may take place in some NSCLC.

Evidence of T cell receptor beta-chain patterns in inflammatory and noninflammatory bowel disease states

T cell activation, as defined by expression of relevant cell surface molecules, such as the interleukin-2 receptor (CD25), is increased in many chronic relapsing diseases, including inflammatory bowel disease (IBD). These T cells are generally activated through contact of their clonotypic T cell receptor (TCR) with a peptide antigen presented by a major histocompatibility complex molecule. One of the putative antigenic contact sites for the TCR is the third complementarity determining region (CDR3) of the TCR beta-chain variable region (TCRBV). Therefore, analysis of the TCRBV CDR3 provides insight into the diversity of antigens encountered by a given T cell population. This study evaluated the TCRBV CDR3 usage of the activated intestinal lymphocytes from human subjects with IBD, diverticulitis (inflammatory control), and a normal tissue control. Public patterns, as demonstrated by shared TCRBV CDR3 amino acid sequences of activated intestinal T cell subpopulations, were observed. In particular, a public pattern of TCRBV22, a conserved valine in the fifth position, and use of TCRBJ2S1 or TCRBJ2S5 was present in three of four Crohn's disease subjects while not present in the ulcerative colitis subjects. However, the private patterns of TCRBV CDR3 region amino acid sequences were far more striking and easily demonstrated in all individuals studied, including a normal noninflammatory control. Thus we conclude that selective antigenic pressures are prevalent among an individual's activated intestinal lymphocytes.

First comparative delineation of the T cell receptor repertoire in primary and multiple subsequent/coexisting metastatic melanoma sites

At present, very little is known about the types and heterogeneity of T cell responses and immunodominant epitopes of melanoma-associated antigens at coexisting sites of primary melanoma and metastatic lesions. To address this issue, we compared the T cell receptor (TCR) gene usage, complementary-determining region 3 diversity, and melanoma-associated antigens expression patterns of primary and metastatic melanoma specimens from three patients with partially homologous HLA class-1 types. Results obtained showed an overall predominance of a very limited number of TCRV regions with AV13 and BV14 being most frequently overexpressed. Sequencing of the dominating TCR transcripts confirmed the restricted usage of certain TCR specificities and, in two of the three patients, identified several identical TCR clonotypes at more than one metastatic site. Nevertheless, we failed to detect TCR transcripts that were common to all tumor deposits in a given patient and, within the majority of coexisting metastases, tumor-infiltrating lymphocytes preferentially used individual site-specifically expanded TCR beta-chain VJ segment combinations. This occurrence of individual responses simultaneously executed at and influenced in their specificity by the different sites of tumor growth, has important implications for the type of strategies chosen in the development of efficacious vaccines for patients with metastatic melanoma.

Future perspectives in specific immunotherapy of melanoma

With the discovery of T-cell recognised tumour-associated antigens (TAAs), interest in specific immunotherapy for treatment of malignancies has increased substantially. The majority of studies investigating TAAs have focused on melanoma-associated antigens because of evidence that the immune system influences the pathogenesis of melanoma. This paper reviews the different types of melanoma antigens, their in vitro and in vivo immunogenicity and clinical data regarding the use of specific immunotherapy in patients with stage I-IV melanoma. Results of clinical studies are highly variable but encourage further research in these patients. Developing and perfecting laboratory and clinical correlates of response to these specific immunotherapies are vital to determining their role in clinical practice.

Generation and characterization of gp100 peptide-specific NK-T cell clones

MHC-restricted cytotoxic T lymphocytes (CTLs) specific for antigens expressed by malignant cells are important components of immune responses against human cancer. Peripheral blood monocytes of HLA-A2+ healthy donors were used to induce dendritic cells (DCs) by granulocyte-macrophage colony-stimulating factor and interleukin-4 and loaded with a gp100 peptide (YLEPGPVTA). By applying these peptide-loaded DCs, a CTL line that displayed high cytotoxic reactivity with peptide-loaded target cells was generated. A total of 11 gp100 peptide-specific CTL clones were generated from this cell line. Several of these CTL clones were studied in detail. Of particular interest was clone CTL-45, which, contrary to the parental cell line, displayed strong NK activity and, by flow-cytometric analysis, revealed a CD3+, TCR BV17, CD8+ and CD56+ phenotype. This clone was strictly peptide-specific and effectively killed a panel of melanoma cells expressing HLA-A2 and gp100. Tumor-specific T cells with this kind of dual function are potentially of great clinical importance as they have a backup mechanism that may go into action when tumor cells escape specific killing by losing their HLA-class I molecules.

Limited T cell receptor Vbeta-chain repertoire of liver-infiltrating T cells in autoimmune hepatitis

BACKGROUND/AIMS

To characterize the cellular immune reactions in autoimmune hepatitis, the T cell receptor repertoire of liver-infiltrating and circulating T cells was studied.

METHODS

Nucleic acids of liver-tissue and peripheral blood-derived T cells from 12 patients with untreated autoimmune hepatitis, four patients with chronic hepatitis C and three patients with toxic liver injury were extracted and analysed using a semiquantitative RT-PCR with a panel of T cell receptor Vbeta family specific primers. After agarose gel electrophoresis, the distribution of T cell receptor (TCR) Vbeta molecules was assessed by densitometry. Furthermore, results were compared to the TCR Vbeta distribution of 10 healthy blood donors.

RESULTS

Four of 12 patients with untreated autoimmune hepatitis but no patients with chronic hepatitis C and toxic liver injury showed a significant overexpression of TCR Vbeta3 (17.8% +/- 2.6% vs. 9.3% +/- 4.6%; p = 0.01) and three an overexpression of Vbeta13.1 (14.6% +/- 2.3% vs. 6.6% +/- 3.5%; p = 0.02) molecules compared to the TCR Vbeta-distribution in healthy blood donors. In addition, Vbeta3+ T cells were found enriched in the liver tissue compared to autologous peripheral blood in three autoimmune hepatitis patients (15.3% +/- 7.0% vs. 5.2% +/- 3.1%; L/B ratio: 2.9), while Vbeta13.1+ T cells were enriched in the liver tissue from one of three patients with overexpression.

CONCLUSIONS

In autoimmune hepatitis a disease specific compartmentalisation of TCR Vbeta3+ T cells was observed in the liver tissues. Although their specificity was unknown, this might indicate that these infiltrating T cells could have relevance for abnormal immunoregulation.

The host-tumor immune conflict: from immunosuppression to resistance and destruction

A successful immune response against a tumor is dependent on the cytokine repertoire present at the tumor site. Salem Chouaib and colleagues discuss evidence that, to escape the immune system, tumor cells not only produce immunosuppressive cytokines but also employ strategies involving altered susceptibility to tumor necrosis factor and Fas cytotoxic pathways and, in some circumstances, use of the Fas ligand to neutralize effector cells.

In vitro T-lymphocyte function in head and neck cancer patients

T-lymphocyte cell function was studied in vitro in peripheral blood mononuclear cells (PBMC) from 61 male patients with head and neck squamous cell carcinomas compared to 46 control patients. Patients older than 80 years or with reduced tumor-related performance status as measured by Karnofsky score less than 75 were excluded. In contrast to previous similar studies, control subjects ensured a minimum stress load by sampling all patients on the day of either diagnostic or therapeutic surgery. PBMC were separated by density-gradient centrifugation and subsequently cultured with autologous sera in vitro. The mitogen concanavalin A (Con A), which stimulates all T-cell clones, was employed. Findings showed that increased Con A stimulation and PBMC proliferation occurred with PBMC from cancer patients compared to that from control patients. In contrast, no differences could be detected with respect to the stimulated supernatant level of interleukin-2, interleukin-4 or interferon-gamma between the groups. These results suggest that T-lymphocytes from PBMC are generally affected by neoplastic disease through either a supporting cell or serum factor.

T cell repertoire in patients with multiple myeloma and monoclonal gammopathy of undetermined significance: clonal CD8+ T cell expansions are found preferentially in patients with a low tumor burden

The T cell receptor (TCR) variable (V) gene repertoire was analyzed in patients with monoclonal gammopathy of undetermined significance (MGUS) (n = 17), multiple myeloma (MM) stage I (n = 16), MM stages II/III (n = 31) and age-matched controls (n = 27) by immunofluorescence and flow cytometry using a panel of mouse monoclonal antibodies (mAb) (n = 10) against TCR V alpha and V beta gene products. T cell expansion was defined as a value > or = thrice the normal median value for each respective TCR V mAb. Fifty-three percent of all patients displayed CD8+ expansion(s) as compared to 30% of age-matched controls (p < 0.001). Within the CD4 subset, 18% of the patients displayed T cell expansion(s) in comparison to 11% of the controls (not significant). Interestingly, the CD8+ expansion(s) were more frequently noted in patients with a low tumor burden (MGUS/MMI) (73%) as compared to those with advanced disease (MM II/III) (32% and control donors (30%) (p < 0.01). Likewise, multiple CD8+ expansions (two or more) were more common in MGUS/MM I patients than in MM II/III and controls (p < 0.01). The T cell expansions were stable over time in patients with a stable disease. A high degree of clonality of the expansions was detected by TCR CDR3 fragment length analysis, determination of J beta gene usage and nucleotide sequencing. The frequent finding of oligoclonal CD8+ T cell expansions in patients with a low tumor mass, but not in patients with advanced disease justifies further work in order to identify the relevance of expanded CD8+ T cells. In one patient with T cell reactivity against the autologous myeloma idiotype, two expansions within the CD8 population (V beta 3 and V beta 5.2 respectively) displayed no reactivity against the idiotype. Instead, idiotype recognition was confined to a CD8 non-expanded V beta 22+ T cell population, with a highly restricted TCR usage (CDR3 fragment length analysis).