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Biomedical subjects

G Parmiani

Publications and source records attributed to G Parmiani.

298 records · Page 17Linked to original sources
PubMedDate not supplied

CEA and NCA expressed by colon carcinoma cells affect their interaction with and lysability by activated lymphocytes.

Heterogeneous lysability by interleukin-2 activated lymphocytes (LAK) and other immune effectors was observed in the human colon-carcinoma lines LoVo/Dx, LoVo/H and HT29. The tumor cells with high susceptibility to LAK (LoVo/Dx, HT29) expressed higher amounts of the adhesion molecules ICAMl, LFA3 and NCA/CEA than cells with low LAK sensitivity (LoVo/H). Monoclonal antibodies against these molecules caused a marked reduction of lysis by LAK of LoVo/Dx and HT29. A pool of these antibodies induced a nearly complete inhibition of the LAK lysis of both lines. Treatment of LoVo/Dx with differentiating agents (dimethylformamide and retinoic acid) led to a decreased expression of the adhesion molecules, including NCA, accompanied by increased resistance to LAK-mediated lysis. Moreover, the presence of CEA soluble antigen drastically inhibited the cytotoxic activity of LAK effectors against HT29 and LoVo/Dx cells, in a dose-dependent manner. These data indicate that sensitivity of colon-carcinoma cells to activated lymphocytes depends on the level of expression of adhesion molecules, including CEA and NCA. Given the role of CEA-related antigens in tumor/lymphocyte interaction, soluble CEA, frequently released by colon-carcinoma, may be involved in immunosuppressive effects induced in vivo by tumor cells.

Antigens, Neoplasm↗
PubMedDate not supplied

Cancer vaccination.

The growth and progression of solid tumours is dependent on several biological factors, such as tumour angiogenesis, appearance of new genetic alterations and/or the failure of the immune defences of the host. Physicians have dreamed of treating cancer with vaccines since the first vaccines against infectious diseases were developed. The identification and availability of tumour-associated antigens now allows the possibility of eliciting humoral (antibody-mediated) and cell-mediated immunity to be tested, which may result in direct or indirect tumour destruction. Thus cancer vaccines have been constructed in order to activate and amplify the patient's immune reaction against tumour-associated antigens. Recent progress in defining the immunogenic epitopes of tumour antigens and in augmenting their immunogenicity (that is their ability to be recognised by and stimulate the immune system of the host), along with the new information on the mechanisms of tumour antigen presentation, has revolutionised the field of cancer vaccines, initially based on non-specific approaches. This review will briefly focus on the biological basis of the development and the clinical application of a wide spectrum of tumour vaccines.

Antibodies, Anti-Idiotypic↗
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Cancer vaccines.

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Animals↗
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An autologous T cell clone overcomes intra-melanoma heterogeneity for susceptibility to cell-mediated lysis by using multiple lytic mechanisms: in vitro and in vivo analysis.

An HLA-A2-specific cytotoxic T lymphocyte (CTL) clone (CTL49), capable of killing the HLA-A2-negative autologous melanoma (Me665/2) in a T cell receptor and MHC-independent fashion, lysed six of 16 Me665/2 tumour clones in short-term (4 and 18 hour) 51Cr-release assays. In long-term (96 hour) lytic assays, CTL49 could lyse all the 16 tumour clones. The lysis observed in the 96 hour assay could be enhanced by stimulating CTL49 with anti-CD3 monoclonal antibodies (MAb) and interleukin-2 (IL-2). Supernatants of anti-CD3- or antigen-stimulated CTL49, known to contain tumour necrosis factor (TNF) alpha and interferon (IFN)gamma, were also able to lyse all but one (665/2/51) of the tumour clones in 96 hour assays. Absence of lysis of tumour clone 2/51 by supernatants correlated with resistance of the same tumour clone to lysis by recombinant IFN-gamma plus TNF-alpha. Antibodies to TNF-alpha and, to a lesser extent, to IFN-gamma, reduced significantly the 96 hour lysis of Me2/9 and Me2/10, two of the tumour clones killed in long term but not in short term assays. Winn assays in nude mice revealed that CTL49, stimulated with anti-CD3-MAb plus IL-2, could abolish tumour cell growth when injected together with clones 2/9 or 2/10. These results indicate that intra-tumour heterogeneity for susceptibility to lysis can be overcome even by a single CTL clone providing that appropriate signals (i.e. anti-CD3-MAb and IL-2) are supplied to an effector able to mediate tumour cell lysis by multiple mechanisms.

Animals↗
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Adoptive immunotherapy with adherent lymphokine-activated killer (A-LAK) cells in glioblastoma multiforme.

Adherent lymphokine-activated killer (A-LAK) activity has been recently differentiated in recombinant interleukin-2 (rIL-2) activated PBL. A pilot study on A-LAK + rIL-2 injection into the post-surgical cavity of glioblastoma-operated patients is ongoing. Preliminary data support the feasibility of this technique, which may improve the antitumor response of the host.

Adult↗
PubMedDate not supplied

Cytokine gene transduction in tumor cells: interleukin (IL)-2 or IL-4 gene transfer in human melanoma cells.

Cytokine gene transfer into mouse tumor cells has been shown to stimulate a strong immune response resulting in the rejection of the transduced tumor when injected in vivo. Therefore, retroviral vectors containing the human interleukin (IL)-2 or IL-4 gene have been constructed to transduce human melanoma cells to explore whether their immunogenicity can be increased both in vitro and in vivo. Our preliminary results indicate that retroviral vectors can efficiently transduce the IL-2 and or IL-4 gene into melanoma clones, inducing production of either cytokine in the range of 0.5-2 ng/ml/10(5) cells in 48-72 h. No modifications of the growth rate, morphology and antigenicity of the transduced tumor cells were found.

Cytotoxicity Tests, Immunologic↗
PubMedDate not supplied

The role of cytokines in the modulation of cell surface antigens of human melanoma.

A number of different cytokines, including IL-1 alpha and beta, IL-2, IL-3, IL-4, IL-6, IL-7, IL-8, IFN-alpha, -beta and gamma, TNF-alpha -beta, and TGF-beta 1, can modulate the expression of distinct cell surface antigens of normal and neoplastic cells. Both induction/increase of expression and reduction of expression can be achieved depending on the antigen and on the cytokine. Antigens subjected to the modulating activity of cytokines include distinct families of cell surface structures such as the molecules coded by the major histocompatibility complex (MHC), the superfamily of adhesion receptors that regulate cell-cell and cell-matrix interaction, receptors for cytokines and growth factors and tumor-associated antigens. The modulating activity of cytokines is a consequence of their influence on gene expression, protein synthesis, membrane expression and shedding of antigens from the cell surface. The changes of phenotype due to the action of cytokines can influence the signalling pathways dependent on the expression and function of cell surface structures. Therefore, the antigen modulating activity of cytokines can thoroughly affect the biological behavior of normal and neoplastic cells. As described here, most of the modulating effects of cytokines on different cell surface structures and the functional consequences of antigenic modulation can be verified in human malignant melanoma cells.

Antigens, Neoplasm↗
PubMedDate not supplied

HLA binding characteristics and generation of cytotoxic lymphocytes against peptides derived from oncogenic proteins.

AIMS AND BACKGROUND: Structurally altered proteins (derived from chromosomal translocations or gene mutations) can be considered tumor specific antigens and represent an attractive target for a T-cell mediated response. T lymphocytes recognize antigens in the form of peptides bound to HLA-molecules. MATERIALS AND METHODS: Peptides derived from oncogenic proteins were screened for the presence of HLA binding motifs; actual binding were evaluated by HLA stabilization experiments using transfectants and specific anti-HLA antibodies. Specific lymphocytes were induced by in vitro peptide sensitization and screened by thymidine uptake or cellular cytotoxic assays. RESULTS: We identified peptides derived from EWS/FLI-1 fusion protein and from mutated K-RAS protein (encompassing respectively the fusion point and the mutation at position 12) that showed binding motif for HLA-Cw*0702 and HLA-A3 respectively. The actual binding of these peptides was analysed in a stabilization assay. We detected binding for the EWS/FLI-1 peptide and for 5 RAS peptides (1 wild type and 4 mutated). The effect of temperature, beta 2-microglobulin (beta 2-m) and fetal calf serum (FCS) on the binding and the stability of the HLA/peptide complex was studied. A low temperature (26 degrees C) increased the binding both in HLA-A3 and HLA-Cw*0702, while FCS reduced it. beta 2-m increased the binding to the HLA-A3 molecule but did not influence the binding to the HLA-Cw*0702. The stability of already formed complexed was somewhat different in the HLA-A3 and HLA-Cw*0702 system: both were more stable at 26 degrees C than at 37 degrees C but while the beta 2-m and FCS did not influence the stability of the HLA-A3/peptide complex, they seemed to cause opposite effects in the HLA-Cw*0702 system (beta 2-m stabilized and FCS destabilized the complex). Finally, we were able to generate a specific CD8+ CTL line against a K-RAS mutated peptide. CONCLUSIONS: Although binding motifs and actual HLA binding can be detected in several cases, the generation of a cellular response is infrequent, confirming that HLA binding is necessary but not sufficient to obtain an in vitro response. Further optimization of culture conditions, type of Antigen Presenting Cells (APC), peptides, use of stabilizers like beta 2-m are still needed.

Cytotoxicity Tests, Immunologic↗
PubMedDate not supplied

Gene transfer into human dendritic antigen-presenting cells by vaccinia virus and adenovirus vectors.

In a search for means to deliver exogenous gene(s) into human dendritic cells (DCs) from the perspective of tumor-specific vaccination, we have evaluated two recombinant viruses, both of which carry a reporter gene which is namely a modified vaccinia virus Ankara (MVA) and an adenovirus, as possible expression vectors. The recombinant MVA-P11 LZ vector carries the Escherichia coli lacZ gene coding for the enzyme beta-galactosidase, and the recombinant Ad-MFG-AP vector carries a modified membrane-exposed alkaline phosphatase (AP) gene. DCs were generated ex vivo in the presence of tumor necrosis factor-alpha, granulocyte macrophage colony-stimulating factor, stem cell factor, and flk-2/flt-3 ligand taken from CD34+ hematopoietic progenitors that were mobilized into the peripheral blood of cancer patients treated with high-dose cyclophosphamide and filgrastim. The target cells used for gene delivery were either CD34+ cells that had been subsequently induced to differentiate into mature DCs or DCs transduced after ex vivo generation from CD34+ cells. The results showed that: (a) infection of CD34+ cell derived-DCs (mature DCs) with either viral vector resulted in the efficient synthesis of recombinant protein, and (b) CD34+ cells were permissive for the expression of the recombinant reporter gene after infection with Ad-MFG-AP but not after infection with MVA-P11 LZ. In conclusion, these results suggest that vaccinia and adenovirus vectors are candidate to act as vehicles in genetically engineering human DCs.

Adenoviridae↗