Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 38
Filter
Add more filters










Publication year range
1.
Oncoimmunology ; 5(10): e1216290, 2016.
Article in English | MEDLINE | ID: mdl-27853637

ABSTRACT

Long synthetic peptides and CpG-containing oligodeoxynucleotides are promising components for cancer vaccines. In this phase I trial, 19 patients received a mean of 8 (range 1-12) monthly vaccines s.c. composed of the long synthetic NY-ESO-179-108 peptide and CpG-B (PF-3512676), emulsified in Montanide ISA-51. In 18/18 evaluable patients, vaccination induced antigen-specific CD8+ and CD4+ T-cell and antibody responses, starting early after initiation of immunotherapy and lasting at least one year. The T-cells responded antigen-specifically, with strong secretion of IFNγ and TNFα, irrespective of patients' HLAs. The most immunogenic regions of the vaccine peptide were NY-ESO-189-102 for CD8+ and NY-ESO-183-99 for CD4+ T-cells. We discovered a novel and highly immunogenic epitope (HLA-DR7/NY-ESO-187-99); 7/7 HLA-DR7+ patients generated strong CD4+ T-cell responses, as detected directly ex vivo with fluorescent multimers. Thus, vaccination with the long synthetic NY-ESO-179-108 peptide combined with the strong immune adjuvant CpG-B induced integrated, robust and functional CD8+ and CD4+ T-cell responses in melanoma patients, supporting the further development of this immunotherapeutic approach.

2.
Tissue Antigens ; 83(4): 237-46, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24641502

ABSTRACT

CD4(+) T cells comprise a large fraction of tumor infiltrating lymphocytes and it is now established that they may exert an important role in tumor immune-surveillance. Several CD4(+) T cell subsets [i.e. T helper (Th)1, Th2, T regulatory (Treg), Th17, Th22 and follicular T helper (Tfh)] have been described and differentiation of each subset depends on both the antigen presenting cells responsible for its activation and the cytokine environment present at the site of priming. Tumor antigen-specific CD4(+) T cells with different functional activity have been found in the blood of cancer patients and different CD4(+) T cell subsets have been identified at the tumor site by the expression of specific transcription factors and the profile of secreted cytokines. Importantly, depending on the subset, CD4(+) T cells may exert antitumor versus pro-tumor functions. Here we review the studies that first identified the presence of tumor-specific CD4(+) T cells in cancer patients, the techniques used to identify the tumor antigens recognized, the role of the different CD4(+) T cell subsets in tumor immunity and in cancer prognosis and the development of therapeutic strategies aimed at activating efficient antitumor CD4(+) T cell effectors.


Subject(s)
Antigens, Neoplasm/immunology , CD4-Positive T-Lymphocytes/immunology , Immunity, Cellular , Neoplasms , Animals , Cytokines/immunology , Humans , Neoplasms/diagnosis , Neoplasms/immunology , Neoplasms/pathology , Neoplasms/therapy
3.
Immunol Today ; 20(10): 457-62, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10500293

ABSTRACT

The identification of human tumor-associated antigens has opened new avenues for immune intervention in cancer. Clinical trials using synthetic peptides that match segments of known tumor-associated proteins are ongoing. Alternatively, naturally processed peptides, obtained by acid treatment of tumor cells can be used. Here, Matteo Bellone and colleagues discuss the advantages and disadvantages of synthetic versus natural tumor peptides in cancer immunotherapy.


Subject(s)
Immunotherapy/methods , Neoplasms/therapy , Amino Acid Sequence , Antigens, Neoplasm/genetics , Clinical Trials as Topic , Humans , In Vitro Techniques , Molecular Sequence Data , Peptides/genetics , Peptides/immunology , Recombinant Proteins/genetics , Recombinant Proteins/immunology , T-Lymphocytes/immunology
4.
J Leukoc Biol ; 66(2): 247-51, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10449162

ABSTRACT

Although the mechanisms regulating recognition and phagocytosis of apoptotic cells by scavenger cells are the subject of intense investigation, little is known about the fate of the antigens contained in apoptotic cells and the constraints defining their immunogenicity. We developed a model in C57BL/6 mice to evaluate whether phagocytosis of apoptotic tumor cells yielded antigens able to get access to the MHC class I pathway and activate a specific cytotoxic T lymphocyte response. Our results demonstrate that apoptotic tumor cells are antigenic in vitro and can be immunogenic in vivo. Their immunogenicity depends on the number of cells used for immunization and the antigen-presenting cells involved in processing and presentation of antigens contained in the dying cells. The demonstration of the immunogenicity of apoptotic cells may have direct implications both in autoimmunity and cancer.


Subject(s)
Antigen-Presenting Cells/immunology , Apoptosis/immunology , T-Lymphocytes, Cytotoxic/immunology , Animals , Antigens/immunology , Histocompatibility Antigens Class I/immunology , Mice , Mice, Inbred C57BL , Ovalbumin/immunology
5.
J Immunol ; 163(1): 130-6, 1999 Jul 01.
Article in English | MEDLINE | ID: mdl-10384108

ABSTRACT

Apoptosis allows the clearance of unwanted cells from living tissues without causing inflammation. Processing of phagocytosed apoptotic cells yields Ags that access the cytosol and the MHC class I pathway of engulfing cells and are recognized by Ag-specific CTL. We show here that injection of apoptotic RMA cells, a syngeneic T cell lymphoma, into C57BL/6 mice results in priming of a functional and long-lasting tumor-specific immune response. Cross-priming of CTLs by apoptotic cells requires CD4+ T cell help. Apoptotic cells, however, are at least 20-fold less immunogenic than nonreplicating live cells. Immunogenicity of apoptotic cells is proportional to the number of cells injected, correlates with the serum concentration of IL-10 and IL-1beta cytokines, and is enhanced in IL-10 knockout mice. Moreover, immunization with dendritic cells (DCs), but not macrophages (Mphi), pulsed with apoptotic cells primes tumor-specific CTLs and confers protection against a tumor challenge. Our findings demonstrate that tumor cells undergoing apoptosis are, though scarcely, immunogenic in vivo, outline the different roles of Mphi and DCs in the physiologic clearance of unwanted cells, and have implications in designing immunomodulating vaccines.


Subject(s)
Antigen-Presenting Cells/immunology , Antigens, Neoplasm/immunology , Apoptosis/immunology , Cytokines/physiology , Adoptive Transfer , Animals , Antigen-Presenting Cells/metabolism , Antigens, Neoplasm/administration & dosage , CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Cell Line, Transformed , Cytokines/metabolism , Dose-Response Relationship, Immunologic , Female , Injections, Intraperitoneal , Lymphoma, T-Cell/immunology , Lymphoma, T-Cell/pathology , Mice , Mice, Inbred C57BL , Mice, Knockout , Neoplasm Transplantation , Phagocytes/immunology , Phagocytes/transplantation , Rauscher Virus , Tumor Cells, Cultured
6.
Nat Biotechnol ; 17(6): 555-61, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10385319

ABSTRACT

Most pockets in the human leukocyte antigen-group DR (HLA-DR) groove are shaped by clusters of polymorphic residues and, thus, have distinct chemical and size characteristics in different HLA-DR alleles. Each HLA-DR pocket can be characterized by "pocket profiles," a quantitative representation of the interaction of all natural amino acid residues with a given pocket. In this report we demonstrate that pocket profiles are nearly independent of the remaining HLA-DR cleft. A small database of profiles was sufficient to generate a large number of HLA-DR matrices, representing the majority of human HLA-DR peptide-binding specificity. These virtual matrices were incorporated in software (TEPITOPE) capable of predicting promiscuous HLA class II ligands. This software, in combination with DNA microarray technology, has provided a new tool for the generation of comprehensive databases of candidate promiscuous T-cell epitopes in human disease tissues. First, DNA microarrays are used to reveal genes that are specifically expressed or upregulated in disease tissues. Second, the prediction software enables the scanning of these genes for promiscuous HLA-DR binding sites. In an example, we demonstrate that starting from nearly 20,000 genes, a database of candidate colon cancer-specific and promiscuous T-cell epitopes could be fully populated within a matter of days. Our approach has implications for the development of epitope-based vaccines.


Subject(s)
DNA/chemistry , Database Management Systems , Epitopes/chemistry , HLA-DR Antigens/chemistry , Alleles , Amino Acid Sequence , Epitopes/immunology , HLA-DR Antigens/genetics , HLA-DR Antigens/immunology , Humans , Ligands , Molecular Sequence Data , Sequence Homology, Amino Acid , T-Lymphocytes/immunology
7.
Int J Cancer ; 81(4): 573-9, 1999 May 17.
Article in English | MEDLINE | ID: mdl-10225447

ABSTRACT

Fas and Fas ligand (FasL) have been found both in lymphoid and in non-lymphoid malignancies, and are thought to play a role in the interplay between tumors and the immune system. Here we investigated Fas/FasL expression, function and intracellular signalling pathways in human melanomas. Of 5 melanoma cell lines, 3 expressed Fas at their surface, and all of them expressed FasL. FasL was functional, since it triggered Fas-induced apoptosis of human T lymphocytes clones. Conversely, cross-linking of Fas molecule with a specific monoclonal antibody failed to induce apoptosis in any of the melanomas tested, or ceramide intracellular accumulation or caspase-3 activation, pointing to an early alteration in the Fas-triggered signaling cascade. All melanomas retained the ability to undergo apoptosis induced by cytotoxic lymphocytes, which was mediated by the granule exocytosis mechanism. This suggests that melanoma cells evade immune-mediated Fas-triggered apoptosis via a selective blockade of the Fas apoptotic pathway. Cytotoxic lymphocytes, however, may circumvent tumor resistance to Fas-induced death via granzyme-mediated apoptosis, further supporting the development of immunotherapeutic strategies in the treatment of cancer.


Subject(s)
Melanoma/immunology , Membrane Glycoproteins/physiology , Signal Transduction/immunology , T-Lymphocytes, Cytotoxic/immunology , fas Receptor/physiology , Antigens, CD/immunology , Apoptosis , Cells, Cultured , Clone Cells , Coculture Techniques , Cytotoxicity, Immunologic , Fas Ligand Protein , Flow Cytometry , Humans , Interleukin-2/pharmacology , Interleukin-2/physiology , Jurkat Cells , Lymphocyte Activation , Melanoma/pathology , Membrane Glycoproteins/genetics , Receptors, Antigen, T-Cell, gamma-delta/immunology , Skin Neoplasms/immunology , Skin Neoplasms/pathology , Tumor Cells, Cultured , fas Receptor/genetics
8.
Cancer Res ; 59(10): 2287-91, 1999 May 15.
Article in English | MEDLINE | ID: mdl-10344730

ABSTRACT

CTLs were generated in vitro from two healthy donors and one melanoma patient by stimulation of CD8+ T cells with autologous dendritic cells pulsed with natural melanoma peptides (NMPs), obtained by acid treatment of HLA-matched melanoma cells. CTLs showed MHC class I-restricted melanoma-specific cytolytic activity. Importantly, CTLs from the patient, induced with NMPs obtained from an allogeneic HLA-A-matched melanoma, killed the autologous tumor. COS-7 cells cotransfected with the cDNA of 13 melanoma antigens and the HLA-A1-restricting allele did not induce cytokines release from NMP-specific CTLs, suggesting that they recognize unidentified shared melanoma antigens and that they may be valuable for identification of new tumor antigens. These results strongly support the use of autologous and/or allogeneic NMP-pulsed dendritic cells as cancer vaccines in patients whose neoplasms do not express or have lost expression of known tumor antigens.


Subject(s)
Antigens, Neoplasm/immunology , HLA-A1 Antigen/immunology , Melanoma/immunology , Peptide Fragments/immunology , T-Lymphocytes, Cytotoxic/immunology , Alleles , Animals , Antigen Presentation , Antigens, Neoplasm/genetics , COS Cells , DNA, Complementary/genetics , Dendritic Cells/immunology , Humans , Recombinant Fusion Proteins/immunology , Transfection , Tumor Cells, Cultured/immunology
9.
J Exp Med ; 189(5): 871-6, 1999 Mar 01.
Article in English | MEDLINE | ID: mdl-10049951

ABSTRACT

In this study we used TEPITOPE, a new epitope prediction software, to identify sequence segments on the MAGE-3 protein with promiscuous binding to histocompatibility leukocyte antigen (HLA)-DR molecules. Synthetic peptides corresponding to the identified sequences were synthesized and used to propagate CD4(+) T cells from the blood of a healthy donor. CD4(+) T cells strongly recognized MAGE-3281-295 and, to a lesser extent, MAGE-3141-155 and MAGE-3146-160. Moreover, CD4(+) T cells proliferated in the presence of recombinant MAGE-3 after processing and presentation by autologous antigen presenting cells, demonstrating that the MAGE-3 epitopes recognized are naturally processed. CD4(+) T cells, mostly of the T helper 1 type, showed specific lytic activity against HLA-DR11/MAGE-3-positive melanoma cells. Cold target inhibition experiments demonstrated indeed that the CD4(+) T cells recognized MAGE-3281-295 in association with HLA-DR11 on melanoma cells. This is the first evidence that a tumor-specific shared antigen forms CD4(+) T cell epitopes. Furthermore, we validated the use of algorithms for the prediction of promiscuous CD4(+) T cell epitopes, thus opening the possibility of wide application to other tumor-associated antigens. These results have direct implications for cancer immunotherapy in the design of peptide-based vaccines with tumor-specific CD4(+) T cell epitopes.


Subject(s)
Antigen Presentation , Antigens, Neoplasm , CD4-Positive T-Lymphocytes/immunology , Cytotoxicity, Immunologic , HLA-DR Antigens/immunology , Melanoma/immunology , Neoplasm Proteins/immunology , Amino Acid Sequence , Cancer Vaccines , Drug Design , Epitopes , Forecasting , HLA-DR Serological Subtypes , Humans , Lymphocyte Activation , Molecular Sequence Data , Peptide Fragments/immunology , Protein Binding , Protein Processing, Post-Translational , Software , T-Lymphocyte Subsets
11.
Hum Gene Ther ; 9(9): 1335-44, 1998 Jun 10.
Article in English | MEDLINE | ID: mdl-9650618

ABSTRACT

Neoplastic cells express tumor-associated antigens, but tumor rejection seldom occurs in vivo. The absence of an effective immune response may be explained by the inability of tumor cells to deliver co-stimulatory signals. Indeed, transfection of either B7-1 or B7-2 co-stimulatory molecules into mouse tumor cells enhances antitumor immune responses. In this study, we stably transfected human melanoma cells with the cDNA encoding the B7-2 molecule to evaluate in vitro: (i) the induction of anti-melanoma cytotoxic T lymphocytes (CTL) by stimulation of CD8+ T cells, purified from healthy donors and a melanoma patient, with B7-2 transfected allogeneic HLA-matched melanoma cells; (ii) the tumor specificity and the HLA restriction of the induced CTL; and (iii) the feasibility to propagate long-term antimelanoma CTL lines. We found that B7-2 transfected, but not untransfected or mock-transfected, melanoma cells activated MHC-class I-restricted, melanoma-specific CD8+ CTL from healthy donors. More importantly, CD8+ tumor-associated lymphocytes, purified from a tumor-invaded lymph node of a melanoma patient and stimulated with B7-2-transfected melanoma cells, acquired a strong reactivity toward the autologous tumor. CTL lines with specific cytolytic activity could be propagated in long-term culture. These results indicate that: (i) the expression of the B7-2 molecule into human melanoma cells makes them immunogenic and able to act as antigen-presenting cells and (ii) purified CD8+ cells, stimulated with B7-2+ allogeneic HLA-matched melanoma cells, preferentially recognize melanoma-specific rather than allogeneic antigens. This study may have clinical implications for passive and/or active immunotherapy in melanoma patients.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , HLA-B7 Antigen/genetics , HLA-B7 Antigen/immunology , Melanoma/genetics , Melanoma/immunology , Transfection , Antigens, Neoplasm/immunology , Cytotoxicity Tests, Immunologic , Flow Cytometry , Histocompatibility Testing , Humans , Leukocytes, Mononuclear , Major Histocompatibility Complex/immunology , Melanoma-Specific Antigens , Neoplasm Proteins/immunology , T-Lymphocytes, Cytotoxic/immunology , Tumor Cells, Cultured
13.
Cancer Res ; 57(13): 2564-8, 1997 Jul 01.
Article in English | MEDLINE | ID: mdl-9205054

ABSTRACT

The immunogenic Friend-Moloney-Rauscher (FMR) virus-induced tumors have been used extensively to clarify the cellular and molecular mechanisms responsible for tumor rejection and to develop immunotherapeutic strategies. We characterize here the trimolecular complex MHC class I-antigenic determinant-T cell receptor involved in the induction of a protective CTL response against the RMA thymoma. This complex is mainly composed by the D(b) molecule interacting with a Rauscher virus antigen (Ag) determinant and the Vbeta5+ T cell receptor. We also show that the chemically induced EL-4 thymoma acquires the susceptibility to recognition by anti-RMA CTLs and the ability to elicit a protective anti-RMA CTL response only upon infection by a virus of the FMR family and that RMA and FMR virus infected EL-4 cells share tumor-associated Ag. The data strongly support the hypothesis that the high immunogenicity of virus-induced or infected tumors is determined by the expression of immunodominant virus-encoded Ag. The demonstration of a different outcome in the immune responses elicited in the presence or in the absence of viral Ag further open the contention of the molecular requirements for immunogenicity and should stimulate a more careful revision of unexpected cross-reactivity among tumors.


Subject(s)
Antigens, Viral/immunology , Immunodominant Epitopes/immunology , Leukemia Virus, Murine/immunology , Lymphoma/immunology , Receptors, Antigen, T-Cell, alpha-beta/immunology , Tumor Virus Infections/immunology , Animals , Cytotoxicity Tests, Immunologic , Female , Friend murine leukemia virus/immunology , Immunohistochemistry , Leukemia, Experimental/immunology , Mice , Mice, Inbred C57BL , Moloney murine leukemia virus/immunology , Neoplasm Transplantation , Rauscher Virus/immunology , Thymoma/immunology , Tumor Cells, Cultured , Vaccination/methods
14.
J Autoimmun ; 10(2): 203-17, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9185882

ABSTRACT

In myasthenia gravis the muscle acetylcholine receptor (AChR) is the target of an autoimmune response. AChR epitopes recognized by CD4+ T cells in myasthenic patients have been identified. AChR-specific CD4+ cell lines can be propagated by stimulation of blood lymphocytes with synthetic or biosynthetic AChR sequences. We analysed, using a semi-quantitative PCR assay, the T cell receptor (TCR) V beta usage of 16 anti-AChR polyclonal CD4+ T cell lines of known epitope specificity, propagated from myasthenic patients using pools of overlapping peptides corresponding to the sequence of an AChR subunit, or individual synthetic AChR sequences. Twelve lines had been propagated for less than 2 months, four lines for 3.5-5 months. Most lines had limited V beta usage, but in most cases different V beta regions were used for different epitopes in the same patient, and for the same epitope in different patients. In a few patients, the same V beta regions were used for recognition of different epitopes. The V beta 4 and V beta 6 regions were used most frequently. These findings suggest that the potentially autoimmune T cells that survive clonal deletion have a limited TCR repertoire. Although the present data do allow conclusions on the role of a superantigen in triggering the anti-AChR autoimmune response, the finding that different V beta regions were used in different patients does not support an important role of a superantigen in the maintenance of the CD4+ response in myasthenia gravis.


Subject(s)
CD4-Positive T-Lymphocytes/metabolism , Myasthenia Gravis/immunology , Myasthenia Gravis/metabolism , Receptors, Antigen, T-Cell, alpha-beta/analysis , Receptors, Cholinergic/analysis , Amino Acid Sequence , Cell Line , Clone Cells , DNA Primers , Epitopes/analysis , Epitopes/genetics , Humans , Molecular Sequence Data , Multigene Family , Polymerase Chain Reaction , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Cholinergic/genetics
15.
J Immunol ; 158(2): 783-9, 1997 Jan 15.
Article in English | MEDLINE | ID: mdl-8992995

ABSTRACT

Naturally processed peptides, obtained by acid extraction of tumor cells, contain Ags able to activate specific CTL in vitro. We recently reported that the nonprofessional APC, RMA-S, expressing the B7.1 molecule (RMA-S/B7), pulsed with naturally processed peptides from the nonimmunogenic B16F1 melanoma (B16F1a.e.) primed syngenic CD8+ T cells against the tumor in vitro. Here, we show the rejection of B16F1 melanoma by C57BL/6 mice after immunization with RMA-S/B7 cells pulsed with B16F1a.e. This response is critically dependent on both CD4+ and CD8+ cells, but not on NK cells. However, only CD8+ T cells exert anti-B16F1 cytolitic activity in vitro. Moreover, RMA-S/B7 cells pulsed with B16F1a.e. can be used to prevent the growth of 24-h preestablished melanomas. These results may have important implications for the clinical use of natural peptide fractions of tumor cells as therapeutic cancer vaccines.


Subject(s)
Antigen-Presenting Cells/immunology , Antigens, Neoplasm/biosynthesis , Antigens, Neoplasm/immunology , Cancer Vaccines/immunology , Graft Rejection/immunology , Melanoma, Experimental/immunology , Vaccines, Synthetic/immunology , Animals , Antigen-Presenting Cells/metabolism , B7-1 Antigen/biosynthesis , B7-1 Antigen/immunology , Female , Killer Cells, Natural/immunology , Mice , Mice, Inbred C57BL , T-Lymphocytes, Cytotoxic/immunology
16.
J Immunol ; 159(11): 5391-9, 1997 Dec 01.
Article in English | MEDLINE | ID: mdl-9548479

ABSTRACT

Programmed death via apoptosis is the metazoan physiologic mode of cell death. Apoptotic cells are recognized by scavenger phagocytes via a number of membrane receptors and engulfed. Thereafter, little is known of their fate, or that of phagocytes. Here, we have traced apoptotic cells upon their engulfment by macrophages. After 3 h, apoptotic cells were contained in discrete well-defined vacuoles. Upon overnight chase, several small vesicles, possibly originating from the fragmentation of original vacuoles, were evident all over the macrophage body. Furthermore, Ags were diffused in the cytosol of some cells, which raises the possibility that epitopes from engulfed apoptotic cells may associate with macrophage MHC class I molecules and be recognized by T lymphocytes. Indeed, Ag-specific CTLs recognize and specifically lyse syngeneic macrophages upon phagocytosis of MHC class I-positive or -negative apoptotic cells, provided that they contain the relevant Ags. Synthesis and membrane expression of class I molecules by macrophages, together with functional transporters associated with Ag presentation, were necessary for recognition and lysis. The indirect presentation of epitopes from engulfed apoptotic cells by scavenger Ag-presenting phagocytes may, in the absence of "danger" signals, have implications for the establishment of central and peripheral self-tolerance.


Subject(s)
Apoptosis , Macrophages/physiology , T-Lymphocytes, Cytotoxic/physiology , Animals , Epitopes/immunology , Female , Histocompatibility Antigens Class I/immunology , Mice , Mice, Inbred C57BL , Phagocytes/physiology , Tumor Cells, Cultured , Vacuoles/ultrastructure
17.
Cancer Res ; 56(6): 1210-3, 1996 Mar 15.
Article in English | MEDLINE | ID: mdl-8640799

ABSTRACT

For an efficient antitumor cytotoxic response, tumor antigenic peptides need to be presented by professional antigen-presenting cells in association with MHC class I molecules. We established in vitro short-term human CTL lines from healthy and melanoma-bearing subjects, using as antigen-presenting cells autologous adherent cells after phagocytosis of latex beads coated with melanoma peptides. Melanoma peptides were obtained by acid extraction of melanoma cells that matched with donor peripheral blood mononuclear cells, at least for one HLA-A allele. The cytotoxic activity of the lines was specific for the melanoma from which peptides were obtained and for melanoma sharing HLA alleles. These results demonstrate that a complex mixture of naturally processed melanoma peptides conjugated to a phagocytic substrate that targets them into the MHC class I pathway of adherent cells can prime a CTL response in healthy subjects in vitro, and that peptides from allogeneic tumors may be used to propagate CTL in melanoma patients. Our data support the feasibility of active and passive vaccination procedures with nonliving vaccines in cancer patients.


Subject(s)
Antigens, Neoplasm/metabolism , HLA-A Antigens/metabolism , Melanoma/immunology , T-Lymphocytes, Cytotoxic/immunology , Animals , Antigen-Presenting Cells/immunology , Antigens, Neoplasm/immunology , Humans , Melanoma/metabolism , Mice , T-Lymphocytes, Cytotoxic/metabolism
18.
Cancer Res ; 56(1): 11-5, 1996 Jan 01.
Article in English | MEDLINE | ID: mdl-8548749

ABSTRACT

In vitro propagation of tumor-specific CTLs, to be used for identification of tumor antigens (Ag) and/or adoptive immunotherapy, is hampered by the need of large amounts of professional antigen-presenting cells (APC) used for periodical cycles of restimulation. We evaluated whether RMA T lymphoma cells, stably transfected with the cDNA encoding for the B7.1 costimulatory molecule, provided the activation signals to CD8+ T lymphocytes in the absence of professional APC and CD4+ helper cells. We demonstrate here that long-term CD8+ cell lines can be efficiently propagated in vitro by repeated cycles of stimulation with tumor cells stably expressing B7.1. Professional APC and CD4+ helper cells are not required as far as interleukin 2 is exogenously provided. Furthermore, CD8+ blasts needed both signal 1 (Ag in the contest of the MHC molecule) and signal 2 (interaction of costimulatory molecules) for restimulation. T cell blasts in the presence of signal 1 or 2 only still retained their effector potential but did not undergo clonal expansion. These results are very promising for further applications of specific immunotherapies in humans.


Subject(s)
Antigen Presentation/immunology , B7-1 Antigen/biosynthesis , CD8-Positive T-Lymphocytes/immunology , Cytotoxicity, Immunologic , Lymphoma, T-Cell/immunology , B7-1 Antigen/genetics , Coculture Techniques , DNA, Complementary/genetics , Gene Expression , Humans , Lymphocyte Activation/immunology , Lymphoma, T-Cell/genetics , Tumor Cells, Cultured
19.
J Immunol ; 154(3): 1508-20, 1995 Feb 01.
Article in English | MEDLINE | ID: mdl-7529806

ABSTRACT

CD8+ cells inhibiting the response of CD4+ cells exist in rodents, recognizing epitopes unique to a CD4+ clone (Ids) or expressed by all activated CD4+ cell (ergotypes). Stimulation of CD8+ cells recognizing ergotypes shared by all Ag-activated CD4+ cells would be useful for treatment of diseases involving undesirable CD4+ responses to ill defined Ags, such as many autoimmune diseases and allergies. As a first step toward demonstrating the existence of anti-ergotype CD8+ immunoregulatory cells in humans, we investigated here whether CD8+ cells recognizing Ag-activated CD4+ cells exist in autoimmune and healthy humans. CD4+ cells specific for human muscle acetylcholine receptor, tetanus, or diphtheria toxoids were propagated from patients with myasthenia gravis patients and healthy controls. Ag-activated CD4+ cells were irradiated and used as Ag to test the response of CD(4+)-depleted CD(8+)-enriched PBMC (CD8+ PBMC) from myasthenic patients and controls and to propagate short-term CD8+ cell lines from CD8+ PBMC. In both patients and controls CD8+ PBMC and CD8+ lines responded vigorously to autologous Ag-activated CD4+ cells. The CD8+ lines responded equally well to the Ag-activated CD4+ cells of different Ag specificity, suggesting that they recognized CD4+ ergotypes. They did not seem to respond to CD4+ cells activated by PHA. The CD8+ cells recognized class I-restricted epitopes, as their response to activated CD4+ cells was suppressed by anti-class I Ab. CD8+ cells recognizing Ag-activated CD4+ were present cells in the controls for 5 to 12 wk after immunization. In myasthenic patients, CD8+ cells recognizing activated anti-acetylcholine receptor CD4+ cells seemed to be always present.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , Lymphocyte Activation/immunology , Myasthenia Gravis/immunology , Adult , Aged , Aged, 80 and over , Antigens/immunology , Cell Line , Diphtheria Toxoid/immunology , Epitopes/immunology , Female , Histocompatibility Antigens Class I/immunology , Humans , Male , Middle Aged , Peptides/immunology , Phytohemagglutinins/immunology , Receptors, Cholinergic/immunology , Tetanus Toxoid/immunology
20.
Eur J Immunol ; 24(11): 2691-8, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7525300

ABSTRACT

Cytotoxic T lymphocytes (CTL) recognize antigenic peptides presented by major histocompatibility complex class I (MHC-I) molecules on the surface of target cells. Optimal induction of CD8+ CTL depends on the amount of relevant peptide/MHC-I complexes and the presence of co-stimulatory molecules on antigen-presenting cells (APC). The antigen-processing defective mutant cell line RMA-S, when cultured at low temperature, expresses high amounts of MHC-I molecules that do not contain endogenously derived peptides. These "empty" MHC-I molecules can be stabilized by addition of MHC-binding peptides. RMA-S cultured at low temperatures with selected peptides have been used for in vitro CTL induction with conflicting results. RMA-S cells do not express detectable amounts of B7 co-stimulatory molecule. This could explain their unpredictable efficiency as APC. We have evaluated whether RMA-S cells, stably transfected with cDNA encoding for the human B7.1 molecule could provide effective co-stimulation for CD8+ T lymphocytes. RMA-S/B7 cells, loaded with different synthetic peptides, demonstrated a high and sometimes unique efficiency for in vitro primary CTL induction, even when "sub-optimal" antigen peptides were used. Most importantly, RMA-S/B7 cells pulsed with naturally processed peptides extracted from the poorly immunogenic B16 melanoma cells were able to prime CD8+ cells against B16 melanoma. We conclude that the use of RMA-S/B7 cells as APC represents an ideal strategy for in vitro CTL immunization without prior in vivo priming. This system may also help to address the issue of the different contributions of co-stimulation and relative occupancy of MHC-I by single peptide epitopes in CTL priming.


Subject(s)
Antigen-Presenting Cells/physiology , B7-1 Antigen/physiology , Epitopes , T-Lymphocytes, Cytotoxic/immunology , Amino Acid Sequence , Animals , B7-1 Antigen/analysis , B7-1 Antigen/genetics , CD8 Antigens/physiology , Female , Histocompatibility Antigens Class I/physiology , Melanoma/immunology , Mice , Molecular Sequence Data , Ovalbumin/immunology , Peptide Fragments/immunology , Transfection , Tumor Cells, Cultured
SELECTION OF CITATIONS
SEARCH DETAIL
...