Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Determinants of T cell responses to tumor cells remain largely unknown. In the present study we have used long-term cultures of human melanoma cells and autologous peripheral blood lymphocytes to examine the influence of cytokines with T cell growth activity on the phenotype and cytotoxic and proliferative response of T cells to melanoma. It was found that addition of interleukin-4 (IL-4) inhibited the response of CD8+ T cells and promoted the response of the CD4 subset. IL-2 or IL-7 was effective in increasing melanoma-specific cytotoxic T lymphocyte (CTL) activity in cultures where CD8 T cells were predominant, whereas IL-4 followed by IL-2 was most effective in cultures where CD4 T cells predominated. IL-10 or IL-12 inhibited proliferation and CTL activity against melanoma in long-term cultures. The effects of IL-12 were reproduced in long-term cultures of T cells stimulated with mAb against CD3 and were shown to depend on prior exposure of T cells to IL-12 before IL-2. As yet unidentified factors, such as co-factor expression on melanoma, appear to be as important as exogenous cytokines in determining the nature of T cell responses to melanoma. These results suggest that analysis of responses in long-term culture may assist in defining the role of key cytokines and other determinants of immune responses to melanoma.
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PMID:Contrasting effects of T cell growth factors on T cell responses to melanoma in vitro. 906 6

Interferon-gamma (IFN-gamma) has the most potent immunomodulatory activity of all the interferons. This phase II-B study was performed to define time- and dose-dependent immunomodulatory effects mediated by IFN-gamma in a subset of patients with melanoma treated in the dose-seeking therapeutic trial conducted by the Eastern Cooperative Oncology Group E4687 (13). The effects of IFN-gamma (Genentech, San Francisco, CA) were evaluated for phenotype and function of peripheral blood lymphocytes obtained twice prestudy, and on days 2, 9, and 29 of IFN-gamma therapy for 50 patients. Early significant increases in CD4/CD8 ratio (p = 0.001) were noted, largely due to a rise in CD4+ and fall in CD8+ T-cell populations sustained through day 29 at only the lowest dosage. Increased natural killer cell (NK) activity (p = 0.001 on day 9; p = 0.01 on day 29) was accompanied by durable increases in circulating activated NK cells (CD56+DR+% p = 0.001, day 9; p = 0.001, day 29). After initial depression of CD56+ and CD16+ cells on day 2, the total percent of CD56+ and CD16+ cells increased significantly by day 29. Increases in NK cell activity were maximal at doses > or =0.1 mg. Monocyte CD14+ expression of DQ+ rose early (p = 0.011 and 0.001 on days 2 and 9), accompanied by elevation in CD14+DR+ cells that was less significant. Immunomodulatory effects of IFN-gamma reported in this trial have major implications for interpretation of past and current clinical trials, and the design of future trials. This is the first trial in which IFN-gamma has been shown to have significant effects on the T-cell compartment of the immune system.
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PMID:Immunomodulatory function of interferon-gamma in patients with metastatic melanoma: results of a phase II-B trial in subjects with metastatic melanoma, ECOG study E 4987. Eastern Cooperative Oncology Group. 908 87

To elucidate the role of NK1.1+ T cells in the antitumor immune response, we established cloned NK1.1+ T cell lines from tumor-infiltrating lymphocytes (TIL) of B16 melanoma, and examined their mode of action in generating antitumor effector T cells both in vitro and in vivo. An NK1.1+ T cell clone (TM4.2) was phenotypically CD3+ TCR-alphabeta+ CD4- CD8- NK1.1+, and CD28+. The TM4.2 cells suppressed the in vitro generation of anti-B16 melanoma CTLs, but not the effector function of CTLs. The results using a transwell membrane suggested that their suppressive activity was mediated by both soluble factors and a direct cell to cell interaction. As for the soluble factors, the suppressive activity of the culture supernatant of TM4.2 cells was neutralized by anti-TGF-beta mAb, and the TM4.2 cells actually produced a considerable amount of TGF-beta. On the other hand, the TM4.2 cells showed a high level of cytolytic activity against B cell blasts and CD80-transfected P815, and such cytolytic activity was reduced by the addition of anti-CD80 mAb. In addition, NK1.1+ T cells in the freshly isolated TIL were revealed to express CD28. Furthermore, the TM4.2 cells suppressed the in vitro generation of anti-allo CTLs irrespective of the MHC haplotype. Finally, the TM4.2 cells suppressed the in vivo antitumor immune response. Collectively, these findings demonstrate that NK1.1+ T cells in TIL show immunosuppressive activity in the antitumor immune response through the production of TGF-beta and the preferential cytolysis of B7-expressing cells.
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PMID:Immunosuppressive activity of cloned natural killer (NK1.1+) T cells established from murine tumor-infiltrating lymphocytes. 914

Membrane immunoglobulin (mIg) M and D heavy chains possess minimal (KVK) cytoplasmic tails and associate with the Ig alpha/Ig beta (CD79) dimer to achieve surface expression and antigen presentation function. In contrast, the cytoplasmic tail of mIgG is extended by 25 residues (gamma ct). We have tested the possibility that mIgG can perform antigen capture and presentation functions independently of the Ig(alpha)/beta dimer. We show that CD4/(gamma)ct chimeras are efficiently endocytosed partially dependent on a tyrosine residue in (gamma)ct. In addition, human mIgG was expressed on the surface of Ig(alpha)/Ig(beta)-negative non-lymphoid cells and mediated antigen capture and endocytosis. Antigen-specific human mIgG targeted antigen to MIIC-type vesicles in the Ig(alpha)/beta negative melanoma Mel JuSo and augmented antigen presentation 1000-fold, identical to the augmentation seen in Ig(alpha)/beta-positive B-cells expressing the same transfected mIgG. Thus, unlike mIgM, mIgG has autonomous antigen capture and presentation capacity, which may have evolved to reduce or eliminate the BCR's dependence on additional accessory molecules.
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PMID:Antigen endocytosis and presentation mediated by human membrane IgG1 in the absence of the Ig(alpha)/Ig(beta) dimer. 923 94

We have transfected human melanoma cell line 518A2 with the cDNA encoding interleukin-2 (IL-2) or granulocyte-macrophage colony-stimulating factor (GM-CSF), and compared cytokine-producing clones for their ability to induce melanoma-specific cytotoxic T lymphocytes (CTL) from autologous peripheral blood mononuclear cells (PBMC) in vitro. The parental cell line expressed HLA-A1, HLA-A2, ICAM-1, LFA-3, in addition to the common CTL antigens MAGE-1, MAGE-3, tyrosinase, gp100, and Melan-A/MART-1. Stimulation of autologous PBMC responders with the IL-2-transfected clone 518/IL2.14 specifically induced CTL lines reactive with all cell lines derived from the autologous patient. Strikingly, GM-CSF-transfected 518A2 cells did not induce anti-tumor CTL reactivity. CTL induction against 518/IL2.14 was independent of HLA class II expression or CD4 help. The parental cell line 518A2 gained immunogenic properties when high concentrations of IL-2 were supplied exogenously, indicating that IL-2 produced and present at high levels locally by itself enhanced immunogenicity. From the autologous CTL line reactive with 518/IL2.14, clones were generated against an as yet unknown antigen, which was present in all autologous melanoma cell lines as well as in 7 of 15 HLA-A2+ melanoma cell lines tested, but not in melanocytes. These results will be discussed with respect to the possibility of using IL-2-transfected melanoma cells as a vaccine for treatment of patients with melanoma.
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PMID:Transfection of IL-2 augments CTL response to human melanoma cells in vitro: immunological characterization of a melanoma vaccine. 933 41

A critical requirement for cancer vaccines is that they stimulate CD8+ T cell responses. In this study, we tested the ability of a polyvalent melanoma vaccine to induce CD8+ T cell responses to the melanoma associated antigens MAGE-3 and Melan A/MART-1. Fifteen HLA-A2+ patients with resected malignant melanoma were immunized with the vaccine s.c. every 2-3 weeks. CD8+ T cells in peripheral blood reacting to HLA-A2 restricted epitopes on MAGE-3 (FLWGPRALV) and Melan A/MART-1/(AAGIGILTV) were quantitated using a filter spot assay at baseline and following 4 immunizations. Vaccine immunization induced CD8+ T cells reacting to one or both of these peptides in 9 of the 15 (60%) patients. These cells were CD8+ and HLA-A2 restricted, as reactivity was abrogated by monoclonal antibodies (MAbs) to CD8 and class I HLA, but not by anti-CD4. All responding patients remained recurrence-free for at least 12 months (median 15 months, range 12 to >21 months), whereas melanoma recurred within 3-5 months in non-responders. The differences in outcome were unrelated to differences in disease severity or overall immunological competence between responders and non-responders. Our results demonstrate directly that MAGE-3 and Melan A/MART-1 can stimulate CD8+ T cell responses in humans, and suggest that these responses are protective and surrogate markers of vaccine efficacy.
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PMID:Stimulation of CD8+ T cell responses to MAGE-3 and Melan A/MART-1 by immunization to a polyvalent melanoma vaccine. 937 60

Previous studies have shown that CD4 T cells are associated with regression in primary melanoma and rejection of tumors in adoptive transfer models. The mechanism by which they mediate their anti-tumor effects remains unclear, and some studies have suggested that Fas ligand (FasL)/Fas interactions were involved. In the present study, we have examined the cytotoxic mechanism involved in CD4 T-cell killing of melanoma cells and, in particular, the role of FasL/Fas interactions in this killing. We show that the CD4 T cells in 4 clones of T cells induced apoptosis in autologous melanoma cells by MHC-restricted mechanisms but lysed an allogeneic melanoma cell by a non-apoptotic mechanism. Melanoma cells expressed both Fas and FasL, but killing of melanoma cells did not involve Fas/FasL interactions. This was shown by a lack of correlation between Fas expression and susceptibility to lysis and by failure of a monoclonal antibody to Fas to block killing by the CD4 T cells, though the latter expressed FasL. Recombinant FasL did not induce killing of melanoma cells.
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PMID:CD4 T cells kill melanoma cells by mechanisms that are independent of Fas (CD95). 945 98

Interferon-alpha (INF-alpha) has a documented activity against metastatic melanoma. To what extent an antiproliferative effect or tumor cell modulation or immunomodulation contributes to this antitumor effect is still uncertain. The role of immune mechanisms in the control of malignant melanoma is suggested by several studies. Therefore, this investigation used monoclonal antibodies, anti-CD4, anti-CD8, and anti-CD11c, to study the occurrence and distribution of tumor-infiltrating mononuclear cells in 10 untreated and 26 IFN-alpha-treated patients with regional metastatic malignant melanoma. IFN-alpha was given for 1-3 weeks before resection of the metastases. The infiltration of mononuclear cells in the stroma and close to tumor cells was studied. The duration of IFN-alpha treatment was found to be of importance for the immunomodulatory effect. In patients treated for < or = 1 week, tumor-infiltrating mononuclear cells were still mainly localized in the stroma, similar to the situation in untreated patients. The differences in CD4+ cells close to the tumor cells, comparing untreated patients and patients with various durations of IFN-alpha treatment, were highly significant (p = 0.009). Thus, IFN-alpha treatment resulted in recruitment of CD4+ cells close to the tumor cells. IFN-alpha had only a weak effect on the recruitment of CD8+ and CD11c+ mononuclear cells close to the tumor cells. Regressive changes in metastases were also analyzed and correlated to duration of treatment. Some of the criteria used for histopathologic regression in primary melanoma (distorted histologic architecture, low tumor cell density, and fibrosis) were applied to analyze the effect of IFN-alpha in metastatic melanoma. The tumor cell density was found to be significantly reduced in metastases with marked tumor regression compared with metastases with no, or only minor, regressive changes (p < 0.005). A chi-square analysis for trend, comparing untreated patients and patients with various durations of IFN-alpha treatment, showed that regressive changes of the tumor increased significantly during IFN-alpha treatment (p = 0.02).
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PMID:Effect of IFN-alpha on tumor-infiltrating mononuclear cells and regressive changes in metastatic malignant melanoma. 947 65

Melanoma is the main cause of death in patients with skin cancer. Cytotoxic T lymphocytes (CTLs) attack melanoma cells in an HLA-restricted and tumor antigen-specific manner. Several melanoma-associated tumor antigens have been identified. These antigens are suitable candidates for a vaccination therapy of melanoma. Dendritic cells (DCs) are antigen-presenting cells (APCs) specialized for the induction of a primary T-cell response. Mouse studies have demonstrated the potent capacity of DCs to induce antitumor immunity. In the present clinical pilot study, DCs were generated in the presence of granulocyte/macrophage-colony stimulating factor (GM-CSF) and interleukin 4 (IL-4) and were pulsed with tumor lysate or a cocktail of peptides known to be recognized by CTLs, depending on the patient's HLA haplotype. Keyhole limpet hemocyanin (KLH) was added as a CD4 helper antigen and immunological tracer molecule. Sixteen patients with advanced melanoma were immunized on an outpatient basis. Vaccination was well tolerated. No physical sign of autoimmunity was detected in any of the patients. DC vaccination induced delayed-type hypersensitivity (DTH) reactivity toward KLH in all patients, as well as a positive DTH reaction to peptide-pulsed DCs in 11 patients. Recruitment of peptide-specific CTLs to the DTH challenge site was also demonstrated. Therefore, antigen-specific immunity was induced during DC vaccination. Objective responses were evident in 5 out of 16 evaluated patients (two complete responses, three partial responses) with regression of metastases in various organs (skin, soft tissue, lung, pancreas) and one additional minor response. These data indicate that vaccination with autologous DCs generated from peripheral blood is a safe and promising approach in the treatment of metastatic melanoma. Further studies are necessary to demonstrate clinical effectiveness and impact on the survival of melanoma patients.
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PMID:Vaccination of melanoma patients with peptide- or tumor lysate-pulsed dendritic cells. 950 May 93

Bi-specific antibody fragments (bAB) are used in tumour therapy as a means to redirect and to strengthen effector cell function. It would be of great therapeutic advantage if, in addition, recruitment, expansion and the state of activity of effector cells are influenced by targeting through a bAB. This question was explored in the melanoma-bearing SCID mouse. The chemically coupled Fab' fragments of an anti-CD3 and an anti-p97 monoclonal antibody (MAB) were characterized in vitro for dual binding specificity and support of lymphokine-activated-killer-cell (LAKC) cytotoxicity towards a highly aggressive human melanoma line, which was significantly increased and exceeded levels of antibody-dependent cellular cytotoxicity observed in the presence of the anti-p97 MAB. The in vivo efficacy was tested in the SCID mouse: 5, 10 and 15 days after i.p. application of tumour cells, mice received LAKC (2 x 10(7)) together with bAB (150-100 microg). The application of bAB was repeated at days 20 and 25. Application of LAKC to melanoma-bearing SCID mice prolonged the mean survival time from 22 days of the untreated control group to 41 days. Anti-p97 did not exert any additive effect. In the presence of bAB, melanoma cells did not grow in 3 out of 8 mice. The mean survival time of the 5 mice developing tumours was 45 days. Importantly, none of the mice receiving bAB developed metastases, which were seen in 100% of animals receiving tumour cells or tumour cells plus LAKC or tumour cells plus LAKC plus anti-p97. As revealed by LAKC recovered from the SCID mice, the efficacy of the bAB was based on prolonged persistence of CD8-positive cells as well as on expansion and activation of CD4-positive cells, which was observed only in bAB-treated tumour-bearing mice. The efficiency in recruiting cytotoxic and, in particular, helper T cells suggests bAB as a valuable additive in immunotherapeutic treatment of melanoma patients.
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PMID:In vivo activation and expansion of T cells by a bi-specific antibody abolishes metastasis formation of human melanoma cells in SCID mice. 950 37


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