Erythropoietin is a major regulator of thrombopoiesis in thrombopoietin-dependent and -independent contexts

Thrombopoietin (TPO), through activation of its cognate receptor Mpl, is the major regulator of platelet production. However, residual platelets observed in TPO- and Mpl-loss-of-function (LOF) mice suggest the existence of an additional factor to TPO in platelet production. As erythropoietin (EPO) exhibited both in vitro megakaryocytic potential, in association with other early-acting cytokines, and in vivo platelet activation activity, we sought to investigate its role in this setting. Here, we used multiple LOF models to decipher the reciprocal role of EPO and TPO in the regulation of platelet production in TPO-LOF and Mpl-LOF mice and of platelet size heterogeneity in wild-type mice. We first identified EPO as the major thrombopoietic factor in the absence of the TPO-Mpl pathway. Based on the study of several mouse models we found that the EPO-EPO receptor pathway acts on late-stage megakaryopoiesis and is responsible for large-sized platelet production, while the TPO-Mpl pathway promotes small-sized platelet production. On the basis of our data, EPO might be used for thrombocytopenia supportive therapy in congenital amegakaryocytopoiesis. Furthermore, as a distribution skewed toward large platelets is an independent risk factor and a poor prognosis indicator in atherothrombosis, the characterization of EPO's role in the production of large-sized platelets, if confirmed in humans, may open new perspectives in the understanding of the role of EPO-induced platelets in atherothrombosis.

In vivo target validation using gene invalidation, RNA interference and protein functional knockout models: it is the time to combine

Most diseases have multifactorial origins and their study requires complex in vivo validation strategies selected for their particular relevance. Most of the in vivo models used to date have been selected according to their availability and the accessibility of the corresponding technology platform. With the rapid development of new technologies, an increasing number of relevant systems for in vivo target validation are now available. In this review, we present in vivo loss-of-function tools acting at three biological levels (the gene, the messenger RNA and the protein); we discuss the specificity of each strategy and how the three techniques can be combined during the validation process in order to overcome the limitations of each one. Thus, combination will broaden the spectrum of the available validation systems and will enable target validation that predicts the situation in humans as accurately as possible.

CD158k/KIR3DL2 is a new phenotypic marker of Sezary cells: relevance for the diagnosis and follow-up of Sezary syndrome

CD158k molecules belong to the family of killer cell immunoglobulin-like receptors (KIR) that are expressed on a minor population of circulating NK and CD8+ T lymphocytes. Here, we report a strong positive correlation between the percentage of CD158k+ blood lymphocytes analyzed by flow cytometry and the percentage of atypical circulating cells (Sezary cells) determined by cytomorphology in a large group of patients with Sezary syndrome. Moreover, we show that circulating CD4+CD158k+ lymphocytes correspond to the malignant clonal cell population. Our findings suggest that the CD158k marker could be a useful tool for the evaluation of the circulating tumoral burden and the follow-up of patients with Sezary syndrome.

Functional and molecular characterization of a KIR3DL2/p140 expressing tumor-specific cytotoxic T lymphocyte clone infiltrating a human lung carcinoma

T lymphocytes infiltrating a human lung carcinoma stimulated in vitro with autologous tumor cell line showed a TCRVbeta13.6(+) T-cell expansion. This subset was isolated using TCRVbeta-specific antibody and several T-cell clones were generated. All these clones expressed a unique Vbeta13.6-Jbeta2.7 TCR with the same junctional region strongly suggesting that they derived from the same cell. They were CD8(+)/CD28(-) and expressed the MHC class I binding killer cell Ig-like receptor (KIR)3DL2/p140, but not KIR3DL1/p70, KIR2DL1/p58.1 and KIR2DL2/3/p58.2. Sequence analysis indicated that KIR3DL2/p140 cDNA was identical to the previously reported 3DL2*002 allele except for two nucleic acid substitutions. Functional studies showed that KIR3DL2/p140(+) CTL secrete a significant level of IFNgamma and mediate an HLA-A2-restricted cytotoxicity against the autologous and some allogeneic tumor cells but not towards the autologous EBV-B cells. Strikingly, both the lytic and the cytokine secretion activities induced upon specific cell interactions were unaffected by anti-KIR3DL2/p140 antibody. In addition, crosslinking KIR3DL2/p140 molecules on CTL did not result into the modification of cytotoxicity and cytokine production triggered by anti-CD3 antibody. These results strongly suggest that, as opposed to distinct KIR expressed by CTL, the in vitro KIR3DL2/p140 engagement does not result into inhibitory (nor activatory) effects on tumor-specific CTL.

A three-dimensional tumor cell defect in activating autologous CTLs is associated with inefficient antigen presentation correlated with heat shock protein-70 down-regulation

We described previously a CTL clone able to lyse the autologous carcinoma cell line IGR-Heu after specific recognition of an HLA-A2/mutated alpha-actinin-4 peptide complex. Here, we used IGR-Heu, cultured either as standard two-dimensional monolayers or as three-dimensional spheroids, to further analyze the influence of target architecture on CTL reactivity. Interestingly, we found that changes in the tumor structure from two- to three-dimensional induced a dramatic decrease in its capacity to activate autologous CTL, as measured by IFN-gamma and tumor necrosis factor-alpha secretion. These functional alterations were attributable neither to MHC class I expression nor to tumor antigen (Ag) down-regulation, because IGR-Heu, cultured as two- or three-dimensional, expressed similar levels of HLA-A2 and alpha-actinin-4. More importantly, incubation of three-dimensional cells with synthetic epitope completely restored cytokine release by CTL. This defective Ag presentation correlated with a decrease in heat shock protein (hsp)70 expression by three-dimensional tumors compared with two-dimensional cells. Furthermore, transfection of the tumor cells with hsp70 cDNA completely restored the Ag-presenting potential of spheroids and, therefore, cytokine production by T cells. These data strongly suggest that hsp70 down-regulation in three-dimensional cells may result in tumor resistance to the immune response.

Potentiation of a tumor cell susceptibility to autologous CTL killing by restoration of wild-type p53 function

Inactivation of p53 has been implicated in many types of tumors particularly in non-small cell lung carcinoma, one of the most common cancers in which p53 mutation has been frequently identified. The aim of this study was to investigate the influence of p53 status on the regulation of tumor susceptibility to specific CTL-mediated cell death. For this purpose, we used a cytotoxic T lymphocyte clone, Heu127, able to lyse the human autologous lung carcinoma cell line, IGR-Heu, in a HLA-A2-restricted manner. Direct genomic DNA sequencing revealed that IGR-Heu expresses a mutated p53 at codon 132 of the exon 5 which results in the loss of p53 capacity to induce the expression of the p53-regulated gene product p21(waf/CIP1). Initial experiments demonstrated that IGR-Heu was resistant to Fas, TNF, and TRAIL apoptotic pathways. This correlated with the lack of p55 TNFRI, Fas, DR4, and DR5 expression. The effect of wild-type (wt) p53 restoration on the sensitization of IGR-Heu to autologous CTL clone lysis was investigated following infection of the tumor cell line with a recombinant adenovirus encoding the wt p53 (Adwtp53). We demonstrate that the restoration of wt p53 expression and function resulted in a significant potentiation of target cell susceptibility to CTL-mediated lysis. The wt p53-induced optimization of tumor cell killing by specific CTL involves at least in part Fas-mediated pathway via induction of CD95 expression by tumor cells but does not appear to interfere with granzyme B cytotoxic pathway.

Recombinant adenovirus shedding after intratumoral gene transfer in lung cancer patients

We conducted two phase 1 trials of direct intratumoral injection of a recombinant E1E3-deleted adenovirus (AdR) encoding either the bacterial enzyme beta-galactosidase (Ad.RSVbetagal) or interleukin 2 (IL2, AdTG5327) into primary nonsmall-cell lung cancers of 21 patients. We report here virus shedding and the duration of virus expression in the tumor after intrabronchial injection of 10(7), 10(8) or 10(9) PFU of adenovirus. The infectious AdR and the viral DNA were detected in PBL, plasma, stool and aerodigestive samples in a dose-dependent manner, since cell cultures and PCRs were found to be positive mainly for samples from patients who received the highest AdR dose (10(9) PFU). We detected beta-galactosidase activity in the tumor biopsy samples of 66% of the patients, seemingly dose related, and only low levels of IL2 mRNA could be detected in tumor biopsy samples. E1 sequences were not detected by PCR in any of the PBL and bronchial samples collected after virus delivery, except in one patient. In this patient, E1 sequences were detected in PBL as well as in tumor biopsy samples collected at days 8, 30 and 60 and were correlated with longer beta-galactosidase expression in tumor samples. PBL tested before and after virus delivery contained both E1 sequences indicating that they did not result from replication-competent adenovirus (RCA) E1 sequences present in the inoculum. In addition, only on the day of the injection was Ad.RSVbetagal also detected in E1-positive PBL, indicating that virus replication in blood was very unlikely.

Isolation of a CD8alphaalpha+ CD4- tumour T-cell clone with cytotoxic activity from a CD4+ CD8- cutaneous T-cell lymphoma

BACKGROUND

We have previously established tumour T-cell lines, both from the skin and from the blood of patients with a cutaneous T-cell lymphoma (CTCL). In one patient, the tumour cells and the derived cell lines had a CD3+ CD4+ CD8- phenotype and a trisomy of chromosome 7. They expressed three T-cell receptor (TCR) beta-chain transcripts, but only one was productively rearranged and expressed at the cell membrane.

OBJECTIVES

In the present study, we tried to isolate a fast-growing new tumour T-cell line from the same patient.

PATIENTS/METHODS

We performed direct cell cloning of the skin tumour lymphocyte population, which led to the isolation of an interleukin-2-dependent highly proliferative T-cell subclone, named Cou-L3, with a CD3+ TCR-Vbeta13+ CD4- CD8alphaalpha+ phenotype.

RESULTS

We demonstrated that Cou-L3 was identical to the original clonal tumour CD3+ Vbeta13+ CD4+ CD8- cells, as it expressed the same rearranged TCR-Vbeta13 chain. We further studied the functional activity of these CD8alphaalpha+ Vbeta13+ Cou-L3 cells. We found that these cells exhibited CD3-redirected cytotoxic activity.

CONCLUSIONS

An immunophenotypic shift, with a change from a CD4+ to a CD8+ phenotype, has been already reported in association with disease progression in CTCL. However, in these cases, there has been no demonstration that the phenotypic change involved the same T-cell clone. The present study is the first report of the phenotypic heterogeneity of the tumour clonal cell population in CTCL.

Antitumor cytotoxic T-lymphocyte response in human lung carcinoma: identification of a tumor-associated antigen

We have isolated several cytotoxic T lymphocyte (CTL) clones from lymphocytes infiltrating a lung carcinoma of a patient with long survival. These clones showed a CD3+, CD8+, CD4-, CD28- phenotype and expressed a T-cell receptor (TCR) encoded either by Vbeta8-Jbeta1.5 or Vbeta22-Jbeta1.4 rearrangements. Functional studies indicated that these clones mediated a high human leukocyte antigen (HLA)-A2.1-restricted cytotoxic activity against the autologous tumor cell line. Interestingly, TCRbeta chain gene usage indicated that CTL clones identified in vitro were selectively expanded in vivo at the tumor site as compared to autologous peripheral blood lymphocytes (PBL). These findings provide evidence that an immune response may take place in non-small cell lung carcinoma and that effector T cells may contribute to tumor regression. Further study indicated that the CTL clones recognized the same decamer peptide encoded by a mutated alpha-actinin-4 gene. Using tetramers of soluble HLA-A2 molecules loaded with the mutated antigenic peptide, we have derived several anti-alpha-actinin-4 T-cell clones from patient PBL. These CTL, recognizing a truly tumor-specific antigen, may play a role in the clinical evolution of this lung cancer patient. Adoptive transfer of CTL clones in a SCID/NOD mice model transplanted with autologous tumor supported their antitumor effect in vivo.

Tumor-infiltrating CD4+ T lymphocytes express APO2 ligand (APO2L)/TRAIL upon specific stimulation with autologous lung carcinoma cells: role of IFN-alpha on APO2L/TRAIL expression and -mediated cytotoxicity

In the present report, we have investigated TRAIL/APO2 ligand (APO2L) expression, regulation, and function in human lung carcinoma tumor-infiltrating lymphocytes. Using a panel of non-small cell lung carcinoma cell lines, we first showed that most of them expressed TRAIL-R1/DR4, TRAIL-R2/DR5, but not TRAIL-R3/DcR1 and TRAIL-R4/DcR2, and were susceptible to APO2L/TRAIL-induced cell death. Two APO2L/TRAIL-sensitive tumor cell lines (MHC class I(+)/II(+) or I(+)/II(-)) were selected and specific CD4(+) HLA-DR- or CD8(+) HLA-A2-restricted CTL clones were respectively isolated from autologous tumor-infiltrating lymphocytes. Interestingly, although the established T cell clones did not constitutively express detectable levels of APO2L/TRAIL, engagement of their TCR via activation with specific tumor cells selectively induced profound APO2L/TRAIL expression on the CD4(+), but not on the CD8(+), CTL clones. Furthermore, as opposed to the CD8(+) CTL clone which mainly used granule exocytosis pathway, the CD4(+) CTL clone lysed the specific target via both perforin/granzymes and APO2L/TRAIL-mediated mechanisms. The latter cytotoxicity correlated with APO2L/TRAIL expression and was significantly enhanced in the presence of IFN-alpha. More interestingly, in vivo studies performed in SCID/nonobese diabetic mice transplanted with autologous tumor and transferred with the specific CD4(+) CTL clone in combination with IFN-alpha resulted in an important APO2L/TRAIL-mediated tumor growth inhibition, which was prohibited by soluble TRAIL-R2. Our findings suggest that APO2L/TRAIL, specifically induced by autologous tumor and up-regulated by IFN-alpha, may be a key mediator of tumor-specific CD4(+) CTL-mediated cell death and point to a potent role of this T cell subset in tumor growth control.

Cytotoxic T lymphocytes directed against a tumor-specific mutated antigen display similar HLA tetramer binding but distinct functional avidity and tissue distribution

We have previously identified an antigen (Ag) recognized on a human large cell carcinoma of the lung by a tumor-specific cytotoxic T lymphocyte clone derived from autologous tumor infiltrating lymphocytes (TILs). The antigenic peptide is presented by HLA-A2 molecules and is encoded by a mutated alpha-actinin-4 (ACTN4) gene. In the present report, we have isolated two anti-alpha-actinin-4 T cell clones from the same patient TIL and from his peripheral blood lymphocytes (PBLs) by using tetramers of soluble HLA-A2 molecules loaded with the mutated peptide. Although all of the clones displayed similar tetramer labeling, those isolated from PBL showed lower avidity of Ag recognition and killed the specific target much less efficiently, indicating that tetramer staining does not correlate with clone avidity/tumor reactivity. T cell receptor (TCR) analysis revealed that alpha-actinin-4-reactive clones used distinct alpha and beta chain rearrangements, demonstrating TCR repertoire diversity. Interestingly, TCR beta chain gene usage indicated that only Ag-specific clones with high functional avidity were expanded at the tumor site, whereas a low-avidity clone was exclusively amplified in patient peripheral blood. Our results point to the existence of distinct but overlapping antitumor TCR repertoires in TIL and PBL and suggest a selective in situ expansion of tumor-specific cytotoxic T lymphocyte with high avidity/tumor reactivity.

Role of p53 in the sensitization of tumor cells to apoptotic cell death

Immunotherapy of cancer has always represented a very attractive fourth-modality therapeutic approach. Over the past few years, advances in the identification of tumor antigens have opened new perspectives and provided new opportunities for a more accurate immunotherapy of cancer. However, when applied to patients with established tumors, it rarely leads to an objective response. This is in part due to the fact that tumors evade host immunity at both the induction and effector phases. In this regard, several different functional defects in T-lymphocytes that infiltrate cancers have been reported. Indeed, lymphocytes of patients with advanced malignancies are hyporeactive and functionally compromised. Furthermore, it has become clear that immunotherapeutic and gene therapeutic approaches aimed at the induction of anti-tumor cytotoxic responses should consider the resistance of tumor cells to cytotoxic mechanisms. Thus, understanding of tumor escape mechanisms may be the key to a successful immunotherapy for cancer. How tumors escape immunological destruction following the acquisition of resistance to cell death and the potential role the tumor suppressor p53 protein in immunosensitization of tumor cells will be discussed.

[Technological advances in immuno-oncology: from fundamental concepts to patient immunological monitoring]

Over the past decade, cancer immunology has known several advances due to both basic research and new technologies recently developed in this field. This review will illustrate the impact of some new immunological technologies and how the latter resulted in the exploration of new territories in cancer immunology and the emergence of new concepts that allowed to revisit the immunosurveillance concept and permitted to improve the patient monitoring.

A point mutation in the alpha-actinin-4 gene generates an antigenic peptide recognized by autologous cytolytic T lymphocytes on a human lung carcinoma

We have identified an antigen recognized on a human large cell carcinoma by an autologous tumor-specific CTL clone that was derived from mononuclear cells infiltrating the primary tumor. The antigenic peptide is presented by HLA-A2 molecules and is encoded by the alpha-actinin-4 gene, which is expressed ubiquitously. In the tumor cells, a point mutation generates an amino-acid change that is essential for recognition by the CTLS: The mutation was not found in alpha-actinin-4 cDNA sequences from about 50 lung carcinoma cell lines, suggesting that it is unique to this patient. Although he did not receive chemotherapy or radiotherapy, the patient has been without evidence of tumor since the resection of the primary lesion in 1996. Using tetramers of soluble HLA-A2 molecules loaded with the mutated antigenic peptide, anti-alpha-actinin-4 CTLs could be derived from blood samples collected from the patient in 1998 and 2000. It is possible that these CTLs, recognizing a truly tumor-specific antigen, play a role in the clinical evolution of this lung cancer patient.

Erythrodermic cutaneous T-cell lymphoma with disseminated pustulosis. Production of high levels of interleukin-8 by tumour cells

Interleukin (IL) -8 is a neutrophil chemoattractant cytokine with proinflammatory and growth-promoting activities, which is involved in the pathogenesis of several inflammatory diseases. It is found in high amounts in lesional biopsies of pustular diseases such as psoriasis and palmoplantar pustulosis. We report a 50-year-old woman with a 10-year history of erythroderma with disseminated pustulosis. Skin biopsies showed an epidermotropic infiltrate composed of atypical CD4+ CD8+ lymphocytes with numerous admixed neutrophils. Peripheral blood flow cytometric analysis revealed a major clonal subset of CD3+ CD4+ CD8+ T-cell receptor Vbeta22+ atypical lymphocytes. Bone marrow biopsy, lymph node biopsy and computed thoracoabdominal tomography were normal. Serologies for human T-cell lymphotropic virus type I and human immunodeficiency virus were negative. Our patient's status deteriorated despite topical (nitrogen mustard, psoralen plus ultraviolet A) and systemic (interferon, methotrexate, multiagent chemotherapy) treatments, and she finally died. We showed that our patient's peripheral blood lymphocytes (PBL) spontaneously produced high amounts of IL-8. In contrast, PBL of patients with classical Sézary syndrome produced lower amounts of IL-8. The production of IL-8 by tumour T cells could explain this unusual clinical and histopathological presentation of cutaneous T-cell lymphoma as disseminated pustulosis.

Role of Fas and granule exocytosis pathways in tumor-infiltrating T lymphocyte-induced apoptosis of autologous human lung-carcinoma cells

We have isolated a cytotoxic T lymphocyte (CTL) clone, Heu161, that reacts specifically with the human autologous lung carcinoma cell line IGR-Heu. We first demonstrated that IGR-Heu lacked Fas-receptor expression and was resistant to CD95-induced apoptosis. To further elucidate the role of Fas in tumor immune surveillance, we have stably transfected IGR-Heu with a Fas-expression vector and isolated CD95-sensitive and -resistant clones. Our data indicated that the resistance of 2 selected Fas-transfected clones to CD95-mediated lysis correlated with down-regulation of caspase-8 or its lack of cleavage and subsequent activation. All Fas transfectants, either sensitive or resistant to anti-Fas agonistic antibody, were as efficiently lysed by the CTL clone as the parental cell line. In addition, neither anti-Fas-blocking antibody nor Fas-Fc molecule inhibited T-cell lysis of Fas-sensitive tumor clone. This cytotoxicity was extracellular Ca(2+)-dependent and abolished in the presence of EGTA, indicating that it was mainly granzyme-mediated. Interestingly, although the caspase inhibitor z-VAD-fmk had no effect on tumor-cell lysis, it efficiently blocked target DNA damage triggered by autologous CTLs via the granule exocytosis pathway, indicating that the latter event was caspase-dependent. The present results suggest that lung carcinoma-specific CTLs use mainly a granule exocytosis-dependent pathway to lyse autologous target cells and that these effectors are able to circumvent alteration of the Fas-triggered intracellular signalling pathway via activation of a caspase-independent cytoplasmic death mechanism.

Role of Fas and granule exocytosis pathways in tumor-infiltrating T lymphocyte-induced apoptosis of autologous human lung-carcinoma cells

We have isolated a cytotoxic T lymphocyte (CTL) clone, Heu161, that reacts specifically with the human autologous lung carcinoma cell line IGR-Heu. We first demonstrated that IGR-Heu lacked Fas-receptor expression and was resistant to CD95-induced apoptosis. To further elucidate the role of Fas in tumor immune surveillance, we have stably transfected IGR-Heu with a Fas-expression vector and isolated CD95-sensitive and -resistant clones. Our data indicated that the resistance of 2 selected Fas-transfected clones to CD95-mediated lysis correlated with down-regulation of caspase-8 or its lack of cleavage and subsequent activation. All Fas transfectants, either sensitive or resistant to anti-Fas agonistic antibody, were as efficiently lysed by the CTL clone as the parental cell line. In addition, neither anti-Fas-blocking antibody nor Fas-Fc molecule inhibited T-cell lysis of Fas-sensitive tumor clone. This cytotoxicity was extracellular Ca(2+)-dependent and abolished in the presence of EGTA, indicating that it was mainly granzyme-mediated. Interestingly, although the caspase inhibitor z-VAD-fmk had no effect on tumor-cell lysis, it efficiently blocked target DNA damage triggered by autologous CTLs via the granule exocytosis pathway, indicating that the latter event was caspase-dependent. The present results suggest that lung carcinoma-specific CTLs use mainly a granule exocytosis-dependent pathway to lyse autologous target cells and that these effectors are able to circumvent alteration of the Fas-triggered intracellular signalling pathway via activation of a caspase-independent cytoplasmic death mechanism.

Differential effect of high doses versus low doses of interleukin-12 on the adoptive transfer of human specific cytotoxic T lymphocyte in autologous lung tumors engrafted into severe combined immunodeficiency disease-nonobese diabetic mice: relation with interleukin-10 induction

BACKGROUND

Interleukin (IL)-12 can enhance the development of effective immune responses against tumors as well as against certain infectious agents. It is therefore a potential candidate for therapeutic use in cancer therapy and in design of vaccines against several infectious diseases.

METHODS

The authors have established a specific cytotoxic T-cell line (TIL-Heu) from lymphocytes infiltrating a human large cell carcinoma of the lung (LCC). In the current report, the authors have investigated the in vivo effect of recombinant human IL-12 (rhIL-12) on the adoptive transfer of TIL-Heu cells in autologous tumor (Heu-n) engrafted into severe combined immunodeficiency disease-nonobese diabetic (SCID-NOD) mice.

RESULTS

Initial in vitro experiments indicated that rhIL-12 increased the cytotoxic potential of TIL-Heu cells in a dose-dependent manner. Heu-n tumors transplanted into SCID-NOD mice were injected with TIL-Heu cells, resulting in a significant tumor growth inhibition. When low doses of rhIL-12 were injected intratumorally after TIL-Heu transfer, a clear increase in tumor growth suppression was observed. Surprisingly, higher doses of rhIL-12 had no effect on cytotoxic T lymphocyte (CTL)-induced prevention of tumor growth. Further in vitro experiments revealed an inhibition of tumor cell lysis after incubation with supernatant of TIL-Heu cells stimulated with high doses of rhIL-12, strongly suggesting that an immunosuppressive factor secreted by the high dose IL-12-stimulated CTL may be responsible for the tumor escape observed in vivo.

CONCLUSIONS

The authors' data indicate that IL-10 may play a critical role in the lack of effect of high dose IL-12, by mediating tumor cell resistance to CTL killing. Therefore, understanding the cross-talk between immunoregulatory and immunosuppressive cytokines ultimately may provide new approaches to improve cytokine-mediated cancer immunotherapy.

Functional inhibitory receptors expressed by a cutaneous T cell lymphoma-specific cytolytic clonal T cell population

Inhibitory receptors on natural killer cells and on a minority of T lymphocytes are major histocompatibility complex class Ia or Ib specific. We have previously reported several tumor-specific cytotoxic T cell clones infiltrating a CD4(+) V beta 13(+) cutaneous T cell lymphoma. These clones mediated a specific major histocompatibility complex class I-restricted cytotoxic activity toward the uncultured tumor cells and autologous long-term tumor T cell lines. In this study, we cultured with interleukin-2 the peripheral blood lymphocytes of the same patient a few weeks before invasion of the blood by tumor cells. We report the rapid and selective expansion of a CD8(+) V beta 13(+) lymphoid population. This population was clonal, as it expressed a unique T cell receptor-V beta junctional region. V beta 13(+) tumor cells and V beta 13(+) reactive T cells were shown to have different junctional sequences. The CD8(+) reactive clone was functional, as it had a specific autologous tumor-specific, human leukocyte antigen-A2 restricted, cytotoxic activity. This clone coexpressed high levels of CD158a, CD158b, p70, and CD94/NKG2A inhibitory receptors. Interestingly, we found that anti-CD158a and anti-CD158b monoclonal antibodies could inhibit anti-CD3 redirected cytotoxicity mediated by the reactive clonal population. Further, an anti-human leukocyte antigen-B/C monoclonal antibody enhanced the specific cytotoxic activity of the clone against autologous tumor cells. These results are the first evidence that inhibitory receptor expression can lead to the inhibition of cutaneous T cell lymphoma-specific T cell responses.

Functional characterization of an IL-7-dependent CD4(+)CD8alphaalpha(+) Th3-type malignant cell line derived from a patient with a cutaneous T-cell lymphoma

CDR3 of the functional rearranged T-cell receptor variable beta region (TCR-Vbeta) transcript was sequenced in order to demonstrate for the first time the identity between a long-term cultured T-cell line derived from a cutaneous T-cell lymphoma (CTCL) patient and the malignant T-cell clone present in the blood. The patient's peripheral blood lymphocyte-derived cultured T-cell line had a CD3(+)Vbeta22(+)CD4(+)CD8alphaalpha(+)CD25(-) phenotype. It was named Pno and had been cultured for more than 1 year. Both fresh and long-term-cultured tumor cells proliferated highly in response to interleukin-7 (IL-7), and exogeneous IL-7 prevented Pno lymphocytes from apoptosis and maintained high levels of Bcl-2 expression. This unique malignant cloned lymphocyte line was further used to carry out functional studies. The results indicated that the CD3/TCR structures expressed by the Pno lymphocytes were functional because an immobilized anti-CD3 monoclonal antibody (mAb) or the combination of a soluble anti-CD3 mAb with submitogenic doses of phorbol 12 beta-myristate 13 alpha-acetate induced a proliferative response. Further, the CD2 and CD28 coreceptors were functional because they were able to induce a strong proliferative response upon their specific stimulation. Finally, the Pno T cell line had a Th3-type cytokine profile because it produced high amounts of the immunosuppressor cytokine tumor growth factor-beta1 (TGF-beta1). This high production of TGF-beta1 may inhibit antitumor specific responses in CTCL.

Cutaneous T cell lymphoma reactive CD4+ cytotoxic T lymphocyte clones display a Th1 cytokine profile and use a fas-independent pathway for specific tumor cell lysis

We have previously described two cytotoxic T lymphocyte clones isolated from lymphocytes infiltrating a human major histocompatibility complex class II-/class I+, CD4+ cutaneous T cell lymphoma. These clones displayed a CD4+CD8dim+ (TC5) and CD4+ CD8- (TC7) phenotype and mediated a specific major histocompatibility complex class I-restricted cytotoxic activity toward Cou-LB autologous tumor cell line. Our studies were performed to elucidate the mechanism involved in T-cell-clone-mediated cytotoxicity and to determine the cytokine profile of both the lymphoma cell line and specific cytotoxic T lymphocyte clones. The results indicate that, despite surface expression of Fas receptor on Cou-LB and Fas ligand induction on TC5 and TC7 cell membranes, the CD4+ cytotoxic T lymphocyte clones do not use this cytotoxic mechanism to lyse their specific target. The TC7 clone uses instead a granzyme-perforin-dependent pathway. Furthermore, quantitative analysis of Th1 and Th2 cytokine mRNA expression in the cutaneous T cell lymphoma cell line as well as in TC5 and TC7 clones indicated that, whereas the tumor cells display a Th2-type profile (interleukin-4, interleukin-6, and interleukin-10), the cytotoxic T lymphocyte clones express Th1-type cytokines (interferon-gamma, granulocyte macrophage colony stimulating factor, and interleukin-2). In addition, preincubation of the tumor-infiltrating lymphocyte clones with autologous tumor cells induced their activation and subsequent amplification of the Th1-type response. These results indicate a direct contribution of the malignant cells in the Th1/Th2 imbalance observed frequently in cutaneous T cell lymphoma patients and suggest their potential role in depressed cell-mediated immunity. Identification of CD4+ Th1-type cytotoxic T lymphocyte clones, the tumor antigen they recognize, and optimization of their cytokine expression profile should be useful for the design of new immunotherapy protocols in cutaneous T cell lymphoma.

Killer inhibitory receptor (CD158b) modulates the lytic activity of tumor-specific T lymphocytes infiltrating renal cell carcinomas

In this study, we showed that renal tumors contain substantial subsets of CD8(+) p58(+) T cells. From 1 of these tumors, T cells were amplified in mixed lymphocytes-tumor cell cultures and p58(+) T cells were selected immunologically. After expansion, phenotypic and functional features of p58(+) and p58(-) T cells were examined. The p58(+) T cells expressed p58.2 receptor and corresponded to CD3(+), CD8(+), T-cell receptor (TCR) alpha/beta(+) T cells that were CD56(+) and CD28(-). Functionally, p58(+) T cells showed a low level of lytic activity against autologous tumor cells that was dramatically and specifically increased by anti-p58.2 monoclonal antibody. On the other hand, p58(-) CD8(+) T cells did not lyse autologous tumor cells and had non-major histocompatibility complex-restricted cytotoxicity against K562 and Daudi cells. A p58(+) cytotoxic T lymphocyte (CTL) clone (4C7) with the same characteristics as the p58(+) T-cell line was derived. This CTL clone did not lyse autologous normal B cells but lysed several HLA-A1(+) renal tumor cell lines. Analysis of TCR repertoire diversity showed that the p58(+) T-cell line contained 3 TCR rearrangements, whereas the TCR repertoire of p58(-) T cells was polyclonal. Interestingly, TCR transcripts of p58(+) T cells and of CTL clone 4C7 were detected as prominent ex vivo in tumor cells but not in peripheral blood mononuclear cells, suggesting that these cells are antigen specific and amplified at the tumor site. (Blood. 2000;95:2883-2889)

Evidence for in situ expansion of diverse antitumor-specific cytotoxic T lymphocyte clones in a human large cell carcinoma of the lung

We have isolated several cytotoxic T lymphocyte (CTL) clones from lymphocytes infiltrating a human large cell carcinoma (LCC) of the lung. All these clones were found to express a CD3(+), TCRalphabeta(+), CD8(+), CD4(-), CD28(-) phenotype. According to their TCR beta chain variable region expression, they were divided in three major groups. The first group, including the majority of the clones, expressed a unique V(beta)3-J(beta)1.2 TCR. The second group expressed a V(beta)22-J(beta)1.4 rearrangement and the third group, including only two clones, expressed a V(beta)8-J(beta)1.5 TCR. Functional studies showed that all the CTL clones mediated a high cytotoxic activity against the autologous tumor cell line. While the V(beta)3(+) clones showed a weak lysis against few allogeneic non-small cell lung cancer (NSCLC) tumor cell lines, V(beta)8(+) and V(beta)22(+) T cell clones were able to kill a panel of allogeneic NSCLC tumor cell lines. Cytotoxicity-blocking experiments using specific mAb indicated that, while the V(beta)3(+) and V(beta)22(+) CTL clones were HLA-A2 restricted, the V(beta)8(+) clones appeared HLA-B or -C restricted. TCR transcripts expressed in the cloned cells were determined by CDR3 size and sequence analyses, and compared to those present in fresh tumor tissue. Interestingly, our studies demonstrated that the CTL clones identified in vitro were selectively expanded in vivo at the tumor site as compared to autologous peripheral blood lymphocytes. These results further provide evidence that an immune response may take place in NSCLC and that effector T cells may contribute to tumor regression.

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.

Quantitative analysis of Th1, Th2 and TGF-beta1 cytokine expression in tumor, TIL and PBL of non-small cell lung cancer patients

For understanding the local immune response in human non-small cell lung cancer (NSCLC), we investigated both Th1 and Th2-type as well as TGF-beta1 cytokine mRNA expression in 10 fresh tumor biopsies, the corresponding tumor and short term TIL cell lines as well as patient PBMC. A methodology based on a highly sensitive quantitative RT-PCR was used. We found that IL-6 mRNA was highly expressed in all tumor biopsy samples analyzed (4 LLC, 3 ADC and 3 SCC). IL-10 mRNA was expressed in 7 of 10 biopsies whereas IL-4 mRNA expression was moderate. Analysis of type I cytokines revealed a low expression level of IL-2 mRNA, while IFNgamma and GM-CSF expression was high in the majority of the tumor lesions studied. Quantitatively, high amounts of Th2-type cytokine mRNA were detected at the tumor site with IL-6 as the predominant lymphokine. A high mRNA expression level of the immunosuppressive cytokine TGF-beta1 was observed in all NSCLC. To identify the cell types responsible for the production of TGF-beta1, IL-6, IL-10 and GM-CSF at the tumor site, tumor and TIL cell lines were derived from the corresponding biopsies. All the 3 tumor cell lines analysed were found to express high amount of TGF-beta1 but not IL-10 mRNA, 2 expressing IL-6 and GM-CSF. Five short term TIL cell lines established in the presence of IL-2 expressed high level of IL-10, IL-4 and IFNgamma but not IL-2 mRNA. Strikingly, high expression of IL-10 mRNA was also observed in all 6 patient PBMC analyzed as compared to controls. Together, our results indicate the existence of a local and peripheral Th-2-type cytokine pattern in patients bearing NSCLC.

Isolation of tumor-specific cytotoxic CD4+ and CD4+CD8dim+ T-cell clones infiltrating a cutaneous T-cell lymphoma

We have isolated several T-cell clones from lymphocytes infiltrating a human major histocompatibility class (MHC) II negative cutaneous T-cell lymphoma (CTCL). We describe here two of these clones, TC5 and TC7, with, respectively, a CD4(+)CD8dim+ and CD4(+)CD8(-) phenotype. Both clones mediated a specific MHC class I-restricted cytotoxic activity toward the fresh autologous tumor cells, and autologous tumor cell lines previously established with interleukin-2 (IL-2) and IL-7 from the skin and from the blood. Analysis of the T-cell receptor (TCR) Vbeta gene expression showed that the tumor cells, which were shown to have a trisomy 7 by fluorescent in situ hybridization, expressed Vbeta7/Jbeta2.3, Vbeta13/Jbeta2.5, and Vbeta22/Jbeta2.5 rearrangements. Phenotypic analysis using specific anti-Vbeta monoclonal antibodies indicated that only Vbeta13 could be detected on the cell membrane of the tumor cells. Analysis of the TCR Vbeta gene expression of the clones showed that TC5 and TC7 expressed a unique TCR-Vbeta transcript, corresponding, respectively, to Vbeta5/Jbeta2.3 and Vbeta17/Jbeta2.7 gene segments. To determine whether these reactive T lymphocytes were present in vivo, we used specific primers corresponding to TC5- and TC7-Vbeta TCR transcripts. The results showed that both cytotoxic T-cell clones were present at the lesional skin site and amplified in vitro. TC7 was found in the patient peripheral blood invaded by tumoral cells, whereas TC5 was not, indicating that the repertoire of the reactional lymphocytes differs in the blood and at the tumor site. These results show for the first time the presence of reactive T lymphocytes with CD4 or double-positive phenotype infiltrating a CTCL. These findings raise the question of the role of these antitumoral effector T cells in the tumor growth.

Characterization of proliferative responses and cytokine mRNA profiles induced by Vespula venom in patients with severe reactions to wasp stings

The reasons why severe allergic reactions to bee and wasp stings develop in only a small portion of exposed individuals are incompletely understood, but differences in T cell responses to venom antigens comparing allergic and non-allergic individuals are likely to be important. To identify such differences, venom-induced proliferative responses and cytokine mRNA production by blood mononuclear cells from Vespula venom-allergic patients and non-allergic individuals were compared. Mononuclear cells from most venom-allergic patients proliferated in response to alkylated Vespula venom (7275 +/- 8387 ct/min, n = 19), and the extent of proliferation was greater for patients with a history of multiple prior stings and those with high levels of venom-specific IgE. Although mononuclear cells from non-allergic subjects showed little or no proliferation in response to venom (926 +/- 711 ct/min, n = 8), production of mRNAs coding for IL-2, IL-4, IL-5, IL-10 and interferon-gamma (IFN-gamma) in response to Vespula venom by cells from non-allergic subjects was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), indicating that these individuals had been previously sensitized to venom antigens. In contrast to the Th0 cytokine mRNA profile observed for non-allergic individuals, venom-allergic patients released a more restricted profile of cytokines following stimulation with venom. Only IFN-gamma mRNA expression was detected in all individuals evaluated, whereas IL-2 mRNA was not detected during the first 48 h of stimulation, and T cells from only one of three venom-allergic individuals produced detectable IL-4 or IL-5 mRNA. The difference in cytokine profiles observed comparing venom-allergic patients and non-allergic controls could not be attributed to intrinsic differences in T cells from these individuals, because polyclonal stimulation with phorbol myristate acetate (PMA) + ionophore induced similar cytokine mRNA profiles in the two groups. These studies demonstrate clear differences in the T cell responses of venom-allergic subjects, that may contribute to the development of severe allergic reactions in these individuals.