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)

The majority of HLA-A*0201-restricted tumor-infiltrating lymphocytes from melanoma patients recognize a peptide, MT(27-35), derived from the Melan-A/MART-1 Ag. This study reports that six variants of HLA-A2 and the HLA-A28 subtype A*6901 can present peptide MT(27-35). A CTL line specific for peptide MT(27-35) was generated by in vitro stimulation of PBL of an HLA-A*0201+, healthy donor with peptide-pulsed, activated autologous B lymphoblasts. This CTL line was shown to recognize peptide MT(27-35) after endogenous processing on Melan-A/MART-1+/HLA-A2+ tumor cells. Moreover, a panel of B lymphoblastoid cell lines (BLCLs) expressing A*0202, A*0204, A*0205, A*0206, A*0209, and with lower efficiency A*6901, could be sensitized to lysis upon incubation with the relevant peptide. As demonstrated by the levels of ED50 and CD8 dependency of lysis, HLA-A*0204 and HLA-A*0205 presented the peptide as efficiently as HLA-A*0201, while the other four alleles were less efficient. Peptide-binding studies suggest that TCR- rather than peptide-binding affinity determines the T cell recognition levels of peptide-pulsed EBV-BLCLs expressing A*0201, A*0204, A*0206, and A*0209. Peptide-pulsed BLCLs expressing HLA-A*0207 or two additional subtypes of HLA-A28 were not recognized. MT(27-35)-specific CTL could also be raised from donors expressing HLA-A*0205. These findings have implications on the applicability of peptide vaccination with peptide MT(27-35) on melanoma patients.
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PMID:Multiple HLA-A alleles can present an immunodominant peptide of the human melanoma antigen Melan-A/MART-1 to a peptide-specific HLA-A*0201+ cytotoxic T cell line. 875 30

The natural history of thyroid tumours and the hyper-reactivity of the immune system in patients with thyroid cancer suggest that immune surveillance may play a role in the control of this disease. A study was therefore undertaken to analyse the phenotypic and functional features of tumour-infiltrating lymphocytes (TILs) derived from thyroid tumours. In a series of experiments, it was found that, in contrast to TILs derived from patients with melanoma or renal cell carcinoma, thyroid TILs could be efficiently expanded in vitro only in the presence of allogeneic EBV transformed B (B. EBV) cells. Indeed, only one of the seven thyroid-derived TILs grew in vitro without feeder cells, whereas all 16 thyroid-derived TILs could be expanded in the presence of allogeneic B. EBV feeder cells. Phenotypic analysis of these TILs revealed a frequent in vitro expansion of an unusual T cell population that expressed both the CD4 and CD8 markers. Indeed, it was demonstrated that in five of 14 TILs in short-term culture (< day 23) and four of 11 TILs in long-term culture (> day 40), a lymphocyte population that coexpressed CD4 and CD8 antigen accounted for more than 15% of the total TIL population. This double-positive T cell population was not observed in TILs derived from melanoma or renal cell carcinoma. Thyroid-derived TILs also displayed an intense cytolytic activity against NK-sensitive tumour targets with 10 of 11 TILs exhibiting significant cytotoxicity towards the NK-sensitive K562 cell line. Six of 11 TILs were also cytotoxic towards autologous tumour, but when cold target inhibition with K562 was performed with three cultures, unlabelled K562 completely inhibited lysis of autologous tumour cells. A significant expansion of CD3+CD56+ T cells in the different TIL populations may explain this high level of NK-like cytotoxicity. In conclusion, TILs derived from thyroid tumours could be efficiently expanded in vitro under certain culture conditions. Different strategies must be explored to enhance their specific tumour autologous specificity, however, before they can be used in immunotherapy protocols.
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PMID:Phenotypic and functional characterisation of tumour-infiltrating lymphocytes derived from thyroid tumours. 875 59

Cytotoxic T lymphocytes (CTL) have previously been isolated from peripheral blood of patients with renal cell carcinoma (RCC). The CD8-positive CTL line MZ1257-CTL-5 (CTL-5) has been shown to lyse autologous cultured RCC cells in an HLA-A2 restricted fashion. Allogeneic, HLA-A2-matched RCC and melanoma cell lines were also lysed by CTL-5, suggesting that melanoma and renal cancer share antigenic determinants. The aim of the study was to determine whether RCC and melanoma share peptide epitopes that are recognized by CTL-5 in the context of HLA-A2 molecules. Peptides were acideulated from various cell lines, separated by reversed phase high performance liquid chromatography (RP-HPLC), and assessed for their ability to reconstitute the CTL-5-defined epitope by pulsing the peptides on HLA-A2 positive antigen-processing mutant cell line CEM x 721.174.T2 (T2). Peptides eluted from allogeneic HLA-A2-matched RCC and melanoma cell lines exhibited the CTL-5-defined epitope in the same HPLC fractions as peptides derived from the autologous RCC line. Renal cancer and melanoma cells preincubated with interferon-gamma (IFN-gamma) resulted in an additional peak of reconstitution activity in both cell types. This second lytic peak was also observed when high amounts of autologous RCC cells were used for peptide preparation without IFN-gamma pretreatment, indicating that IFN-gamma increases the amount of MHC class I/peptide complexes per cell, rather than inducing a neo-epitope.
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PMID:Recognition of human renal cell carcinoma and melanoma by HLA-A2-restricted cytotoxic T lymphocytes is mediated by shared peptide epitopes and up-regulated by interferon-gamma. 879 23

The in vitro cytotoxic response to human melanoma is characterized by CD3+ CD8+ T-cells which recognize shared peptide antigens presented in the context of HLA class-I-encoded gene products. We report here studies of a CD3+, CD4+, CD8-, HLA-A2-restricted, melanoma-specific cytotoxic T-cell clone derived by limiting dilution from a T-cell line induced in PBLs from a melanoma patient following in vitro stimulation with an HLA-A2-matched melanoma cell line. The CD4+ cytotoxic T-cell clone is lytic only for melanomas which share the HLA-A2 allele, and the cytotoxicity is blocked by antibody to the T-cell receptor and by antibody to HLA class I. The clone proliferates only following stimulation with HLA-A2-matched melanoma tumor cells. The data suggest that cytotoxic CD4+ T-cells may play a significant role in immunity to melanoma, and HLA class-I-restricted recognition of melanoma may not necessarily require the CD8 molecule on the lytic T-cell.
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PMID:Recognition and lysis of human melanoma by a CD3+, CD4+, CD8- T-cell clone restricted by HLA-A2. 880 6

Interferon alpha (IFN-alpha) has a documented activity against malignant melanoma with a response rate of only approximately 20%. It would therefore be of considerable importance if patients likely to respond could be identified. The degree of mononuclear cell infiltration in primary tumours has been reported to correlate with a favourable prognosis. This investigation used monoclonal antibodies, anti-CD4, -CD8 and -CD11c, to identify subsets of tumour-infiltrating mononuclear cells in fine needle aspirates to study whether the presence of such cells correlates with the therapeutic effect of IFN-alpha. Twenty-one patients with systemic and 20 with regional metastatic malignant melanoma were studied before initiation of IFN-alpha treatment. A statistically significant correlation (P < 0.001) was found between the occurrence of CD4+ lymphocytes in fine needle aspirates and the therapeutic benefit of IFN-alpha in patients with systemic disease. Ten out of 11 with moderate to high numbers of infiltrating CD4+ lymphocytes achieved tumour regression. In contrast, among patients with low numbers of these cells in metastatic lesions, nine out of ten had progressive disease. Similar results were found in patients with regional disease.
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PMID:Tumour-infiltrating lymphocytes in metastatic malignant melanoma and response to interferon alpha treatment. 884 94

It has been postulated that IL-2 secreting cancer vaccines establish antitumor immunity because the cytokine acting in a paracrine fashion would deliver a helper signal directly to the T cells making contact with the modified tumor cells at the site of vaccination. However, patterns of lymphocyte recirculation cannot be reconciled with the above direct interaction model: only primed memory T cells rather than naive T lymphocytes patrol the periphery, while naive T cells travel to the peripheral lymph nodes, where priming occurs. We have found that in vivo treatment of mice with the antibody MEL-14 directed against L-selectin, which is a molecule expressed at high levels on naive T cells, can completely abrogate protection against a mouse melanoma conferred by an IL-2 secreting vaccine. Since mouse memory CD4 and CD8 T cells are L-selectin-low, only migration of naive T cells is perturbed by the in vivo antibody blockade. Thus, priming of naive T cells in the draining lymph node is a critical step for the successful vaccination by IL-2 secreting cancer vaccines. Such priming is performed most efficiently by professional antigen presenting cells; consequently, these data also imply that allogeneic origin of tumor vaccines may not exclude successful vaccination.
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PMID:Depletion of naive T cells of the peripheral lymph nodes abrogates systemic antitumor protection conferred by IL-2 secreting cancer vaccines. 887 31

CD4 T-lymphocytes, which orchestrate immune responses, receive a cognitive signal when clonally distributed receptors are occupied by MHC class II bound peptides on antigen-presenting cells. The latter provide costimulatory or accessory signals through macromolecules such as B7.1 and B7.2 which interact with coreceptors on T-cells to regulate outcomes in terms of T-cell activation or specific non-responsiveness. Complementary studies at the chemical level have implicated Schiff base formation between specialised carbonyls and amines, constitutively expressed on antigen-presenting cell and T-cell surfaces, as an essential element in specific T-cell activation. The small xenobiotic Schiff base forming molecule tucaresol, which substitutes for the physiological donor of carbonyl groups to provide a costimulatory signal to CD4 T-helper lymphocytes (Th-cells), has been developed for testing as an immunopotentiatory drug. Tucaresol, which is orally bioavailable and systemically active, enhances CD4 Th-cell and CD8 cytotoxic T-cell responses in vivo and selectively favours a Th1-type profile of cytokine production. In murine models of virus infection and syngeneic tumour growth it has substantial therapeutic activity. Schiff base formation by tucaresol on T-cell surface amines provides a costimulatory signal to the T-cell through a mechanism that activates clofilium-sensitive K+ and Na+ transport. The signalling pathway utilised by tucaresol converges with T-cell receptor signalling at the level of MAP kinase, promoting the tyrosyl phosphorylation of ERK2 by MEK (mitogen-activated protein kinase kinase). The Schiff base forming class of immunopotentiatory drug provides the first orally active, mechanism-based immunopotentiatory agents for therapeutic testing. Tucaresol is currently undergoing pilot phase I/II clinical trials as an immunopotentiator in chronic hepatitis B virus infection, HIV infection and malignant melanoma.
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PMID:Schiff base forming drugs: mechanisms of immune potentiation and therapeutic potential. 889 54

Mouse B16 melanoma cells maintained in vitro in the presence of interferon (IFN)-alpha become resistant to the in vitro antiproliferative effects of IFN-alpha. However, IFN-alpha-treated mice inoculated with these in vitro IFN-treated cells (B16 alpha res cells) have significantly increased life spans (ILS) and significantly higher cure rates than IFN-alpha-treated mice inoculated with B16 cells. This unexpectedly greater sensitivity of B16 alpha res cells to the in vivo antitumor effects of IFN-alpha was evaluated by in vivo cell depletion experiments. Depletion of either activated peritoneal macrophages or cytotoxic T lymphocytes (CTL) reduced the ILS of IFN-treated B16 alpha res-inoculated mice to a level comparable to that of IFN-treated B16-inoculated mice. Depletion of natural killer (NK) cells did not affect the ILS for IFN-treated B16 alpha res-inoculated mice. These studies indicate that activated macrophage and CD8 cell function, but not NK cell function, is important for the enhanced antitumor effects induced by IFN-alpha against B16 alpha res cells. Macrophage killing was unlikely to be mediated by TNF-alpha or IL-1 as B16 and B16 alpha res cells were equally sensitive to TNF-alpha and insensitive to IL-1 in vitro. Further, H-2K antigen expression is significantly more readily inducible on B16 alpha res cells than on B16 cells, consistent with enhanced CD8-mediated killing due to increased MHC class I antigen expression.
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PMID:Enhanced in vivo sensitivity of in vitro interferon-treated B16 melanoma cells to CD8 cells and activated macrophages. 891 Jul 65

Selectively-bred Sinclair miniature swine exhibit a high incidence of congenital malignant melanoma which either proves fatal (10-15% of tumor-bearing piglets) or spontaneously regresses with a biphasic immunological phenomenon (85-90%) and no recurrence of malignancy. Mononuclear leukocytes were isolated from cutaneous melanomas and peripheral blood specimens collected from melanomatous (tumor-bearing) Sinclair swine during second-phase regression, and from peripheral blood specimens collected from non-melanomatous (tumor-free) Sinclair swine and control Hanford swine. Leukocyte identities were determined with single- and dual-parameter indirect immunofluorescence assays via flow cytometry. Assays for the specific surface antigens CD45, CD2, CD4, CD8, CD1, MHC class II, and N1 were employed to develop immunophenotypic profiles within the gated lymphocyte clusters from each TIL and PBL suspension. Significantly more CD8+ T-lymphocytes were identified in TIL suspensions than in peripheral blood leukocyte (PBL) suspensions (P < and = 0.05), regardless of breed or tumor status. Conversely, PBL suspensions contained significantly higher percentages of CD4+ T-lymphocytes than the levels found in TIL suspensions (P < and = 0.05). Virtually all TIL were MHC class II+, whereas the percentages of PBL expressing this antigen were markedly lower (P < and = 0.05). The percentages of T-lymphocytes co-expressing CD4 and CD8, a normal subset unique to swine, were generally consistent in all TIL and PBL suspensions examined. The results of this study have firmly established the immunophenotypic identities of cells associated with the second-phase regression phenomenon of this melanoma and have identified specific variations in the leukocyte profiles of the respective TIL and PBL suspensions.
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PMID:Immunophenotypic characterization of tumor infiltrating lymphocytes and peripheral blood lymphocytes isolated from melanomatous and non-melanomatous Sinclair miniature swine. 901 17

The mechanism by which murine tumour-infiltrating lymphocytes (TIL) decreased their anti-tumour activity during an in vitro culture with interleukin-2 (IL-2) was investigated. A phenotype analysis revealed that the TIL cultured for 7 days (TIL-d7) were exclusively NKI.1- CD4- CD8+ CD3+ cells and that this population was replaced by natural killer (NK)1.1+ CD4- CD8 CD3+ cells by day 27 (TIL-d27) during the culture of TIL. The TIL-d7 cells showed a cytolytic activity against B16 melanoma, whereas the TIL-d27 cells had lost this activity, suggesting that the decrease in the anti tumour effect of TIL during the culture with IL-2 was due to their populational change. Analysis on the characteristics of the TIL-d27 cells revealed that they expressed skewed T-cell receptor (TCR) V beta 5 and increased mRNA expression of V alpha 14. In addition, they expressed transforming growth factor beta (TGF-beta) mRNA. Interestingly, TGF-beta augmented the proliferation of TIL-d27 cells under the presence of IL-2, but suppressed that of TIL-d7 cells. Moreover, the proliferation of TIL-d27 cells was suppressed by anti-TGF-beta monoclonal antibody. Collectively, these results suggest that, in contrast to its suppressive effect on anti-tumour effector T cells. TGF-beta could be an autocrine growth factor for NKL1.1+ T cells and thereby induce non-cytolytic NK1.1+ T cells in the long-term culture of TIL.
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PMID:The emergence of non-cytolytic NK1.1+ T cells in the long-term culture of murine tumour-infiltrating lymphocytes: a possible role of transforming growth factor-beta. 901 32


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