T-cell-receptor engagement and tumor ICAM-1 up-regulation are required to by-pass low susceptibility of melanoma cells to autologous CTL-mediated lysis

Tumor-specific and non-specific CD3⁺, TcRαβ⁺, CD8⁺ cytotoxic T-cell (CTL) clones, isolated from tumor-infiltrating lymphocytes (TIL) or peripheral blood lymphocytes (PBL) of a melanoma patient and allogeneic LAK cells, were used to investigate the requirements for bypassing the low lysability of some melanoma clones derived from an S.C. metastasis from which highly lysable clones were also obtained. Cytofluorimetric analysis showed that all melanoma clones expressed ICAM-1, although to different extents, reaching a 10-fold difference in fluorescence units, while HLA class-1 antigens were similarly expressed. The differences in expression of ICAM-1 among tumor clones correlated with differences in lysability, by both specific and non-specific CTL, but were not large enough to affect lymphocyte-tumor conjugate formation. Cytokine- or gene-transfer-mediated up-regulation of ICAM-1 did not induce de novo lysis of ICAM-1^low tumor cells; however, it markedly enhanced a low level of killing of the same cells by tumor-specific, TcR-dependent and HLA-restricted CTL clones but not by non-specific, TcR-independent effectors. In addition, lysis of melanoma clones by any effector was similarly inhibited by anti-ICAM-1 and anti-LFA-1 antibodies. This indicates that by-pass of low lysability of ICAM-1^low melanoma clones by CTL clones, after ICAM-1 up-regulation, is possible only if simultaneous LFA-1 and TcR engagement takes place. In addition, these results suggest that the constitutive high level of expression of ICAM-1 on the subset of ICAM-1^high melanoma cells must be only one of the factors contributing to the high lysability of these cells by any effector.     

Establishment of an immortalized T-cell line from lung cancer tissue: phenotypic and functional analyses

Background. In order to investigate host defense against solid tumors, valuable information could be provided by ex-vivo analyses of functional immune cells in tumor tissues. However, available sources of fresh tumor-infiltrating T cells (TIL) are usually very limited, and it is often difficult to establish TIL lines. In this study, we analyzed the phenotypic and functional characteristics of TIL, using an immortalized cell line prepared by cotransfection of human c-myc and c-Ha-ras. Methods. A human T-cell line was established by cotransfecting c-Ha-ras and c-myc oncogenes to T lymphocytes freshly isolated from human lung large-cell carcinoma tissue. The phenotypes were assessed by flow cytometry. T-cell receptor (TCR) Vα- and β-usage was analyzed by polymerase chain reaction (PCR) and Southern blot. Cytotoxic activity against autologous and allogeneic tumor cell lines was examined by standard ⁵¹Cr-release cytotoxicity assays. Cytokine production by the established T-cell line, 904-T1, in response to stimulation by autologous tumor cells was assayed by using an enzyme-linked immunosorbent assay. Results. 904-T1 (CD3+, CD8+, CD56+, CD16-, CD161-, TCR Vα 9, 13, and Vβ 1, 5) displayed a broad range of MHC-nonrestricted tumoricidal activity against various human tumor cell lines, but did not lyse autologous B cells transformed by Epstein-Barr virus. The cytotoxicity of 904-T1 was not mediated by a T-cell antigen receptor or by Fas-ligand, but by perforin-based cytolytic pathways, and was enhanced by interleukin (IL)-12. 904-T1 cells produced large amounts of interferon (IFN)-γ, but not tumor necrosis factor (TNF)-α or IL-4 in response to autologous tumor cells, and produced high levels of IFN-γ and TNF-α, and a substantial level of IL-4 following stimulation with anti-CD3 monoclonal antibody. Conclusions. Our results suggest that 904-T1 cells were natural killer T (NKT)-like cells with regard to their nonspecific killing, cytokine repertoire, and sensitivity to IL-12, although the repertoire of the TCR variable region was not compatible with that of NKT cells. Received: January 22, 2001 / Accepted: December 19, 2001     

Effect of TNF-α and IFN-γ on the expression of inducible nitric oxide synthase gene and proliferation inhibition of human colon cancer cell line

Objective: To study the expression of the inducible nitric oxide synthase (iNOS) gene and the effects of tumor necrosis factor-α(TNF-α) and interferon-γ(IFN-γ)on proliferation of the continuous cultured human colon cancer cell line CCL229. Methods: Using the molecular and biochemical techniques and electron microscopy to analyze the expression of iNOS, production of NO and growth characteristics of human colon cancer cells. Results: cytokine treatment can induce expression of the iNOS gene and production of nitric oxide was significantly higher after treatment of CCL229 cells with TNF-αor IFN-γ. Treatment with either cytokine or a combination of both significantly increased levels of Malondialdehyde (MDA) over control. Furthermore, cytokine treatment increased the proliferation inhibition rate as assessed in vitro and decreased the cell proliferation index on flow cytometry. Electron microscopy showed that cells treated with cytokines had fewer pseudopodia or cell processes than control cells and that cytokine treated cells had dilatation of the mitochondria and endoplasmic reticulum and dilated vesicular or tubular cisternae. Conclusion: Our findings indicate that TNF-α and IFN-γ induce the expression of iNOS gene in CCL229 cells, which increases the production of nitric oxide, inhibits proliferation, causes lipid peroxidation, and results in ultrastructural changes.     

Stratification by risk factors predicts survival on the active treatment arm in a randomized phase II study of interferon-gamma plus/minus interferon-alpha in advanced renal cell carcinoma (E6890)

Introduction: Standard therapy for recurrent or metastatic renal carcinoma includes the biologic response modifiers interferon-alpha (IFN-α) and interleukin-2 (IL-2). The response rate for both agents is modest and toxicity is significant. New agents are needed. Interferon-gamma (IFN-γ) is a type II interferon that demonstrated promising activity in renal carcinoma in early clinical trials. In vitro data suggested synergistic activity when IFN-γ was combined with IFN-α. The Eastern Cooperative Oncology Group conducted a randomized phase II trial to confirm the efficacy of IFN-γ as a single agent and to evaluate the efficacy and toxicity of IFN-γ in combination with IFN-α in the treatment of patients with metastatic or recurrent renal carcinomas. Materials and Methods: Ninety-five patients with recurrent or metastatic renal carcinoma were entered on trial. Patients were stratified based on risk assessment using the Elson method. Patients were randomly assigned to receive either IFN-γ 0.1 mg/m² weekly (arm A) or IFN-γ 0.3 mg/m² iv daily × 5 every 3 wk plus IFN-α 10 MU/m² daily (arm B). Treatment efficacy was evaluated every 6 weeks. Results: Toxicity in the arm A was minimal. Significant toxicity was noted in arm B, with four cases of grade 4 neurotoxicity. No responses were seen with IFN-γ alone. Five responses (two CR and three PR) were noted in the combination arm for an overall response rate of 10%. Four of five responders were classified as “good risk.” Median survival for arm A was 7.0 mo vs 10.4 mo for arm B. Risk stratification was significant in arm B. Conclusion: IFN-γ at this dose and schedule failed to demonstrate activity in metastatic/recurrent renal carcinoma. The combination of IFN-γ and IFN-α demonstrated a response rate similar to IFN-α alone. There was no evidence of synergy between IFN-γ and IFN-α. deceased     

BCG (bacille Calmette-Guérin)-activated lymphocytes (BAK cells) induce apoptosis in urinary bladder carcinoma cell line T24 in vitro

Background. We previously reported the basic characteristics of BCG (bacille Calmette-Guérin)-activated killer (BAK) cells, which exhibited antitumor effects against the bladder cancer cell line T24. Our study suggested that both BCG and BAK cells were responsible for the inhibition of tumor cell proliferation; however, the basic mechanism of BCG or BAK cells in this inhibition was not clear. We here report the antitumor effects of BAK cells, which correlated with the induction of apoptosis in T24 cells. Methods. Lymphocytes were cultured with BCG to examine ³H-thymidine uptake, and the subpopulation was evaluated by immunocytometry. T24 cells were then cultured with BAK cells for the analysis of ³H-thymidine uptake and apoptosis induction by DNA electrophoresis; pathology study, and cell-cycle analysis were also done. Culture supernatants of BAK and T24 cells were also investigated to detect interferon-γ (IFN-γ), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Results. The ³H-thymidine uptake study of lymphocytes showed that BCG activated the lymphocytes. Evaluation by immunocytometry revealed that CD4⁺ and CD8⁺ T cells were induced by BCG. The ³H-thymidine uptake study of T24 cells revealed that BAK cells inhibited tumor cell proliferation. DNA electrophoresis, the morphological study, and cell-cycle analysis by immunocytometry demonstrated that apoptosis in T24 cells was induced when they were cultured with BAK cells. IFN-γ, IL-6, and TNF-α were detected in the culture supernatants of BAK and T24 cells. Conclusions. Cytokine production and the induction of apoptosis may, together, be the major mechanisms of the antitumor action seen when BAK cells were employed against T24 cells; BAK cells could be employed as clinical effectors against bladder cancer. Received: January 7, 2000 / Accepted: April 27, 2000     

Autologous adjuvant linked fibroblasts induce anti-glioma immunity: implications for development of a glioma vaccine

Summary Objectives: Adjuvant-linked vaccines have been shown to induce anti-tumor immunity in patients with a variety of solid tumors. In this study we describe anin vitro model of active immunotherapy using autologous fibroblasts as immunogen. Correlative results from glioma patients immunized with autologous fibroblasts are also described. Methods: Peripheral blood lymphocytes (PBLs) from normal subjects were immunizedin vitro against autologous skin fibroblasts coupled to the adjuvant muramyl dipeptide. The lymphocytes developed cell-mediated cytotoxicity that was measured with a short-term chromium release assay. Results ofin vitro experiments were compared to data derived from glioma patients immunized with subcutaneous injection of an autologous adjuvantlinked fibroblast vaccine. Glioma target cells and fibroblast immunogens were derived from early passage primary tissue culture. Results: A comparison of autologous vs. homologous immunogen indicated that major histocompatibility complex matching was required at the sensitization stage of immunity (17.2±3.4% specific lysis vs. 0.4±3.1%,P<0.01). Pre-treatment of fibroblast immunogen cells with interferon gamma (IFN-γ) was found to significantly increase immunity (42.2±10.0%,P<0.01), as did IFN-γ pre-treatment of tumor target cells (35.8±9.0%,P<0.01). The positive effect of IFN-γ was diminished by treatment of cells with IFN-α. Thesein vitro results correlated well within vivo data derived from glioma patients immunized with an autologous adjuvant-linked fibroblast vaccine. PBLs from patients developed direct cell-mediated cytotoxicity against autologous tumor cells. Lysis of tumor targets afterin vivo immunization increased over a three-week interval (from 1.2 ± 3.0% to 21.0 ± 3.4%,P < 0.01) while lysis of a non-MHC matched control cell line remained essentially unchanged. Conclusions: Specific lysis of glioma targetsin vitro was achieved afterin vivo sensitization with autologous adjuvant-linked fibroblasts. Collectively, the data indicate that biochemically modified autologous cells can stimulate anti-glioma immunity in humans. The degree of specific immunity seen in our patients compares favorably with other published series using glioma cells as an antigenic source. Accordingly, fibroblasts may represent a practical alternative to glioma cells for vaccine construction.     

Renal-cell carcinoma-specific lysis by cytotoxic T-lymphocyte clones isolated from peripheral blood lymphocytes and tumor-infiltrating lymphocytes

Melanoma and renal-cell carcinoma (RCC) are generally considered to be relatively immunogenic tumor types in humans. In the case of melanoma, many major histocompatibility complex (MHC) class I-restricted tumor-specific cytotoxic T lymphocytes (CTL) have been isolated from either tumor-infiltrating lymphocytes (TIL) or autologous peripheral blood lymphocytes (PBL). In contrast, such CTL have only incidentally been described in the case of RCC. It has often been reported that TIL lines isolated from RCC display non-MHC-restricted and non-specific activity. Here, we report the isolation and characterization of tumor-specific CTL from PBL of one RCC patient and from TIL of another RCC patient. CTL clones 263/17 and 263/45, isolated from the PBL of patient LE-9211, were restricted by HLA-B7. CTL clone 5E, isolated from the TIL of patient LE-8915, was restricted by HLA-B37. The autologous RCC cell lines were efficiently lysed by the CTL clones, whereas normal epithelial cells of the proximal tubuli matched for the restriction element and K562 were not. From a panel of allogeneic RCC cell lines, CTL 5E recognized MZ-1940-RCC. Reactivity to allogeneic RCC sharing HLA-B7 was also observed with CTL 263/17 and 263/45, both of which could lyse the HLA-B7-positive cell line MZ-1851-RCC. Our data provide evidence that common tumor antigens are recognized by CTL on RCC. © 1996 Wiley-Liss, Inc.     

Activation of mononuclear cells to be used for hybrid monoclonal antibody-induced lysis of human ovarian carcinoma cells

Recently we reported that cytotoxic T-cell clones can be retargeted to unrelated tumor cells by bispecific monoclonal antibodies (MAbs), anti-CD3 and anti-ovarian carcinoma (alpha OC/TR) (Mezzanzanica et al., 1988). In the perspective of in vivo tumor immunotherapy, as an alternative to cytotoxic T lymphocytes (CTL) from T-cell clones, since human peripheral blood mononuclear cells (PBMCs) without stimulation were quite ineffective, a suitable in vitro activation method was developed to render PBMCs lytic for relevant targets in the presence of the bispecific hybrid MAb alpha OC/TR. This activation protocol was applied to PBMCs from 9 healthy donors (HD) and 6 ovarian carcinoma patients (P) and to tumor-associated lymphocytes (TAL) from 4 ovarian carcinoma P. The method consisted of in vitro stimulation with phytohemagglutinin (PHA) for 2 days, followed by culture with a low dose of recombinant human interleukin-2 (rIL-2) for 6 to 10 days. The antibody-mediated lysis of CTL from HD PBMCs was found to be specifically directed against cells expressing the relevant ovarian tumor antigen when different tumor cell lines and short-term cultures of tumor and normal cells were tested. The antibody-mediated lysis of CTL from P PBMCs or TAL was efficient both on autologous and allogeneic ovarian tumor cells, whereas no reactivity with autologous normal cells was observed and LAK activity was only evident in 1 out of 4 cases. The hybrid antibody induced cytotoxic activity of CTL from P was, however, lower than that of CTL from HD.     

A phase-I clinical study of autologous tumor cells plus interleukin-2-gene-transfected allogeneic fibroblasts as a vaccine in patients with cancer

Tumor cells transfected to express immunostimulatory cytokines, or admixed with similarly modified bystander cells, are able to induce immune responses against unmodified tumor cells in animal models. For treatment of human patients, a vaccine composed of autologous tumor cells and IL-2-secreting allogeneic fibroblasts was developed. Autologous tumor cells were isolated from biopsy specimens. A clone (KMST6.14) of an immortalized human fibroblast line that stably secreted 5290 IU IL-2 per 10⁶ cells and per 24 hr was obtained by cationic lipofection with an expression construct for human IL-2 and Neo^r. Fifteen patients with refractory malignant tumors received 3–4 injections of irradiated KMST6.14 and autologous tumor cells in a phase-I clinical trial. Increasing transient inflammatory responses without systemic toxicity developed at vaccination sites and after injections with irradiated tumor cells only (p < 0.05). These sites contained a dense infiltrate of CD3⁺ T cells with numbers of CD4⁺ helper cells exceeding those of CD8⁺ cytotoxic T cells (CTL). CD8⁺ T-cell lines isolated from vaccination sites of 2 malignant melanoma patients but not of renal-cell carcinoma patients exhibited a dominant lytic activity against autologous tumor cells in vitro. CD8⁺ T-cell clones established from the vaccination site of 1 of 2 renal-cell carcinoma patients preferentially lysed autologous and partially matched allogeneic renal-cell carcinoma cells. In conclusion, a vaccine composed of IL-2 gene-transfected allogeneic fibroblasts and autologous tumor cells is able to enhance specific anti-tumor T-cell responses in vivo without major side-effects. Malignant melanoma and renal-cell carcinoma appear to be promising entities for testing of similar approaches in future therapeutic trials. Int. J. Cancer, 70:269–277, 1997. © 1997 Wiley-Liss, Inc.     

Lysis of human pancreatic adenocarcinoma cells by autologous hla-class I-restricted cytolytic T-lymphocyte (CTL) clones

From the primary site of a pancreatic adenocarcinoma (patient BE) a permanent cell line (MZ-PC-2) was established in tissue culture. In the course of mixed lymphocyte-tumor-cell cultures (MLTC) with autologous blood-derived lymphocytes, we isolated CTL clones that lysed autologous tumor cells but not autologous EBV-transformed B cells (EBV-B) and not K562. Pre-treatment of MZ-PC-2 cells with IFN-γ was required to obtain significant lysis in 4-hr cytotoxicity assays. IFN-γ was superior to IFN-α in that respect. Among MLTC responder lymphocytes, tumor-reactive CTL proliferated more strongly in response to MZ-PC-2 cells treated with IFN-γ than to untreated tumor cells. Three CTL clones derived from MLTC were chosen for further analysis. They were CD3+, CD8+, TCR-α/β⁺ and behaved identically in all functional aspects tested. They all expressed the same TCR-β chain, indicating that they descended from a common precursor lymphocyte and were directed against the same antigen. According to antibody-inhibition experiments, BE-CTL recognized their targets via an HLA-B molecule carrying the Bw6 supertypic determinant. Irrespective of pre-incubation with IFN-γ, low levels of tumor-cell lysis, or none, were seen when MZ-PC-2 cells were kept in medium supplemented with autologous serum or serum pooled from healthy volunteers instead of FCS. Lysability was restored when TNF-α was added to human serum. Serum-free medium was found to enhance the susceptibility of MZ-PC-2 cells to lysis by autologous CTL.     

Brefeldin A Blocks the Cytotoxicity of T Cell Receptor α/β and γ/δ Cytotoxic T Lymphocyte Clones Reacting against Human Autologous Cancer Cells

We studied the effector mechanism of T cell receptor (TCR) α/β - and γ/δ -type cytotoxic T lymphocyte (CTL) clones that react with human autologous tumor cells. Treatment of tumor cells with a fungal antibacterial reagent, brefeldin A (BFA), resulted in the inhibition of cytotoxicity of an autologous tumor (HST-2)-specific CD8⁺ TCR α/β -type CTL, TcHST-2. Other anti-metabolites such as chloroquine, cycloheximide and colchicine did not affect the cytotoxicity. The cell-surface antigen expression, including MHC class I molecules, was not influenced by BFA treatment. Furthermore, BFA did not influence the cytotoxicity of lymphokine-activated killer cells and natural killer cells. Since BFA blocks the transport of peptides from endoplasmic reticulum to the Golgi apparatus, the above data suggest that BFA could affect washing out of the peptide fragments from the MHC class I groove. Consequently, target tumor cells were protected from killing by CTL, Moreover, we obtained a CD4⁻, 8⁻, TCR γ/δ -type (Vδ1⁺) CTL clone, TcHOT, that reacts against an autologous ovarial carcinoma, HOT. BFA could also inhibit this cytotoxicity, and it is likely that different presenting molecules other than MHC class I proteins participate in the cytotoxicity of this TCR gm/δ - type CTL. These studies suggest that both TCR α/β - and γ/δ -type CTL may require antigenic peptides that are most likely derived from the BFA-sensitive, intracellular endogenous target proteins.     

靶动脉灌注NaHCO3提高部分抗肿瘤药物疗效的基础及临床研究

Objective: To observe the influence of pH value on the proliferation of LAK cells and on the killing effect of rIL-2,IFN-α2b, TNF-α, LAK cells and doxorubicin on malignant tumor cells, and investigate the possibility of increasing the efficacy of rIL-2 or IFN-α2b and doxorubicin by infusing sodium bicarbonate (NaHCO3) through target arteries. Methods: Separating single nucleus cells from peripheral blood of healthy men, and observing the influence of pH on the activation of single nucleus cells by rIL-2. MTT assay was used to measure the killing effect of rIL-2, IFN-α2b and TNF-α on 7404 cells and the increased effect of doxorubicin on rIL-2 and IFN-α2b, the cytotoxity of LAK cells in different pH. Forty-two patients with advanced primary liver cancer were obtained by stratified random, NaHCO3, rIL-2/IFN-α2b and doxorubicin were infused through target arteries. The efficacy was estimated after two cycles. Results: The conditions of pH 7.3 and pH 7.6 in vitro helped the proliferation of LAK cells and the killing effect of rIL-2, IFN-α2b and LAK cells on 7404 cells. In the condition of pH 6.8 there was almost no killing effect for LAK cells. In the condition of pH 7.0, 7.2, 7.4 and 7.6, the killing rate of TNF-α to 7404 cells increased by degrees, and in pH 7.4 the killing effect was the optimum. After two cycles treatments in the 42 patients with advanced primary liver cancer,the response rate (CR PR) was 88% (37/42). The median overall response and median overall survival were increased, and no complication associated with infusing sodium bicarbonate was observed. Conclusion: The killing effect of rIL-2, IFN-α2b, TNF-αand doxorubicin on malignant tumor cells was enhanced by increasing the pH value.     

Lysis of cancer cells by autologous T cells in breast cancer pleural effusates treated with anti-EpCAM BiTE antibody MT110

In the present study, the efficacy of a new drug, i.e. the bispecific single-chain antibody MT110 targeting the epithelial antigen EpCAM and the T-cell antigen CD3 was tested ex vivo in malignant pleural effusions (MPEs). EpCAM⁺ epithelial cells were found in 78% of the MPEs (n = 18). Ex vivo treatment of seven MPEs resulted in a dose-dependent specific lysis of 37 ± 27% (±SD) EpCAM⁺ cells with 10 ng/ml (P = 0.03) and 57 ± 29.5% EpCAM⁺ cells with 1,000 ng/ml MT110 (P = 0.016) after 72 h. As a prerequisite for redirected lysis, stimulation of the autologous CD4⁺ and CD8⁺ cells in MPE by 1,000 ng/ml MT110 resulted in 21 ± 17% CD4⁺/CD25⁺ and 29.4 ± 22% CD8⁺/CD25⁺ cells (P = 0.016, respectively) after 72 h. This was confirmed by a 22-fold release of TNF-α and 230-fold release of IFN-γ (1,000 ng/ml, 48 h, P = 0.03, respectively). Thus, relapsed breast cancer patients resistant to standard treatment might benefit from targeted therapy using MT110.     

Cytotoxic T-cell clone against rectal carcinoma induced by stimulation of a patient's peripheral blood mononuclear cells with autologous cultured tumor cells

In an effort to establish cytolytic T lymphocytes (CTLs) against colorectal carcinoma (CRC) by stimulating patients' lymphocytes with autologous tumor cells, we used peripheral blood mononuclear cells (PBMC) from a patient with minimal residual rectal carcinoma following removal of the primary lesion and involved regional lymph nodes as a source to generate CTLs in culture. A CTL line and clone were established from the patient's PBMC following stimulation of PBMC with autologous, cultured tumor cells and interleukin-2. The CTL line and the clone consisted predominantly of CD4⁺ lymphocytes. The CTL clone expressed two T-cell receptor variable α chains (Vα11 and Vα22) and one β chain (Vβ14). The cytokine secretion pattern of the CTL line was of the Th1-type. Both the CTL line and the clone lysed the autologous rectal carcinoma cells, but not the allogeneic, partially human lymphocyte antigen (HLA)-matched or nonmatched CRC cells, autologous Epstein-Barr virus-transformed B cells, K562 (natural killer target) cells or Daudi (lymphokine-activated killer target) cells. Lysis of autologous tumor cells most likely was HLA class I-restricted. Our unique success in generating CTLs against this tumor type may rest in the inclusion of a patient with minimal residual, rather than advanced, disease. Int. J. Cancer 71:325-332, 1997. © 1997 Wiley-Liss Inc.     

Generation of autologous tumor-specific T cell clones from a patient with adenosquamous carcinoma of the lung

BACKGROUND: Adenosquamous carcinoma of the lung is not a common cancer, but its prognosis is worse than that of adenocarcinoma or squamous cell carcinoma. Therefore, new therapeutic strategies need to be developed to treat this type of lung cancer. Recently, vaccination using tumor antigens which are recognized by cytotoxic T lymphocytes (CTL) has been applied mainly to melanoma patients. We therefore attempted to establish T cell clones specific for autologous tumor cells (AT) from a patient with adenosquamous carcinoma in order to analyze the specific immune responses against AT. METHODS: A lung adenosquamous carcinoma cell line was established from a resected tumor obtained from a 72-year-old patient. Regional lymph node lymphocytes were stimulated weekly with CD80-transfected AT to induce CTL. The CTL activities were assessed by a standard (51)Cr release assay and by cytokine release. RESULTS: We succeeded in inducing an AT-specific CTL line. Using a limiting dilution method, eight T cell clones were established. AT-specific activity was observed in three CD8(+) T cell clones and one CD4(+) T cell clone out of the eight clones tested. Anti-HLA class I and anti-HLA-B/C mAbs inhibited IFN-gamma production from the AT-specific CD8(+) clones co-cultured with AT, thus indicating the restriction element to be HLA-B*5201 or HLA-Cw*1202. In contrast, the CD4(+) T cell clone recognized AT in an HLA class II-restricted manner. CONCLUSIONS: These results are the first demonstration of a successful induction of AT-specific T cell clones from a patient with lung adenosquamous carcinoma. It may therefore supply a possible way to apply specific immunotherapy to this type of lung cancer.     

Generation of diverse mutated tumor antigen-specific cytotoxic T lymphocytes in a lung cancer patient with long survival

We have identified an antigen recognized on a large cell carcinoma of the lung by tumor-specific cytotoxic T lymphocytes (CTL). The antigenic peptide is encoded by a mutated alpha-actinin-4 gene and presented by human leukocyte antigen (HLA)-A2. Using HLA-A2-peptide tetramers, we have derived from patient peripheral blood lymphocytes (PBL) and autologous tumor infiltrating lymphocytes (TIL) several mutated alpha-actinin-4-specific T cell clones. These clones displayed similar tetramer staining but distinct T cell receptor (TCR) usage and antitumor reactivity. Indeed, TIL clones lysed more efficiently the autologous tumor cells and released higher cytokine levels than PBL clones. Importantly, treatment of cancer cells with interferon-gamma enhanced their susceptibility to PBL clone-mediated lysis correlated with increase in HLA-class I expression. The present findings provide evidence that an immune T cell response took place in a lung cancer patient with favorable clinical evolution and suggest that CTL, recognizing a truly tumor-specific antigen, may contribute to controlling the tumor.     

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.     

Immunogenic variants obtained by mutagenesis of mouse lewis lung carcinoma. Recognition of variant-specific antigens by cytolytic T lymphocytes

By mutagenesis of a cell line derived from Lewis lung carcinoma (3LL), it is possible to obtain at high frequency stable tumor cell variants (tum⁻) that are rejected by syngeneic mice. The possibility of obtaining a cytolytic T cell (CTL) response directed specifically against these tum⁻ variants was examined. With the four variants that were analysed, a significant cytolytic activity was obtained with peritoneal cells from immune mice collected shortly after an intraperitoneal boost and also with spleen cells after a secondary stimulation in vitro. The CTL populations preferentially lysed the immunizing tum⁻ variant, while also showing a cross-reactive lysis against the other variants and the original 3LL cells. Highly active CTL clones could be isolated from limiting dilution microcultures of these CTL populations. The clonal analysis clearly showed the existence of two distinct CTL populations, one directed exclusively against the immunizing variant and another that lysed all 3LL targets equally. This CTL specificity analysis therefore demonstrates directly the presence of new antigens on the 3LL tum⁻ cell variants.     

Differential expression and role of p21<Superscript>cip/waf1</Superscript> and p27<Superscript>kip1</Superscript> in TNF-α-induced inhibition of proliferation in human glioma cells

Background  

The role of TNF-α in affecting the fate of tumors is controversial, while some studies have reported apoptotic or necrotic effects of TNF-α, others provide evidence that endogenous TNF-α promotes growth and development of tumors. Understanding the mechanism(s) of TNF-α mediated growth arrest will be important in unraveling the contribution of tissue associated macrophages in tumor resistance. The aim of this study was to investigate the role of Cyclin Dependent Kinase Inhibitors (CDKI) – p21^cip/waf1 and p27^kip1 in TNF-α mediated responses in context with p53 and activation of NF-κB and Akt pathways. The study was done with human glioma cell lines -LN-18 and LN-229 cells, using monolayer cultures and Multicellular Spheroids (MCS) as in vitro models.