RESUMEN

The development of successful cancer vaccines is contingent on the ability to induce effective and persistent anti-tumor immunity against self-antigens that do not typically elicit immune responses. In this study, we examine the effects of a non-myeloablative dose of total body irradiation on the ability of tumor-naïve mice to respond to DNA vaccines against melanoma. We demonstrate that irradiation followed by lymphocyte infusion results in a dramatic increase in responsiveness to tumor vaccination, with augmentation of T cell responses to tumor antigens and tumor eradication. In irradiated mice, infused CD8(+) T cells expand in an environment that is relatively depleted in regulatory T cells, and this correlates with improved CD8(+) T cell functionality. We also observe an increase in the frequency of dendritic cells displaying an activated phenotype within lymphoid organs in the first 24 hours after irradiation. Intriguingly, both the relative decrease in regulatory T cells and increase in activated dendritic cells correspond with a brief window of augmented responsiveness to immunization. After this 24 hour window, the numbers of dendritic cells decline, as does the ability of mice to respond to immunizations. When immunizations are initiated within the period of augmented dendritic cell activation, mice develop anti-tumor responses that show increased durability as well as magnitude, and this approach leads to improved survival in experiments with mice bearing established tumors as well as in a spontaneous melanoma model. We conclude that irradiation can produce potent immune adjuvant effects independent of its ability to induce tumor ablation, and that the timing of immunization and lymphocyte infusion in the irradiated host are crucial for generating optimal anti-tumor immunity. Clinical strategies using these approaches must therefore optimize such parameters, as the correct timing of infusion and vaccination may mean the difference between an ineffective treatment and successful tumor eradication.

Asunto(s)

Vacunas contra el Cáncer/inmunología , Neoplasias/inmunología , Neoplasias/terapia , Traslado Adoptivo , Animales , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/inmunología , Autoantígenos/genética , Autoantígenos/inmunología , Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer/genética , Células Dendríticas/inmunología , Modelos Animales de Enfermedad , Femenino , Humanos , Inmunización , Oxidorreductasas Intramoleculares/genética , Oxidorreductasas Intramoleculares/inmunología , Melanoma Experimental , Ratones , Ratones Transgénicos , Neoplasias/genética , Especificidad del Receptor de Antígeno de Linfocitos T , Linfocitos T Reguladores/inmunología , Factores de Tiempo , Resultado del Tratamiento , Vacunas de ADN/inmunología , Irradiación Corporal Total

RESUMEN

How the immune system recognizes and responds to mutations expressed by cancer cells is a critical issue for cancer immunology. Mutated self-polypeptides are particularly strong tumor-specific rejection antigens for natural tumor immunity, but we know remarkably little about T-cell responses to mutated self during tumor growth in vivo, including levels of response, kinetics, and correlates that predict tumor rejection. To address these questions, a mutated self-antigen, designated tyrosinase-related protein 1 (Tyrp1)-WM, derived from Tyrp1 was expressed in the poorly immunogenic, spontaneously arising B16 melanoma and the immunogenic, chemically induced LiHa fibrosarcoma. Syngeneic mice challenged with LiHa fibrosarcoma cells expressing Tyrp1-WM, but not native Tyrp1, induced specific CD8(+) and CD4(+) T-cell responses against defined mutated epitopes in tumor-draining lymph nodes and in tumors. Subsequently, specific CD8(+) T-cell responses contracted as a minority of tumors progressed. B16 melanomas expressing Tyrp1-WM induced minimal T-cell responses, and no tumor immunity was detected. Treatment with an agonist monoclonal antibody against glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) increased the level of CD8(+) T cells recognizing a peptide derived from the Tyrp1-WM sequence and the proportion of mice rejecting tumors. These results show that B16 tumors expressing mutations that generate strongly immunogenic epitopes naturally induce T-cell responses, which are insufficient to reject tumors. Immune modulation, such as inducing GITR signaling, is required to enhance CD8(+) T-cell responses to specific mutations and to lead to tumor rejection.

Asunto(s)

Autoantígenos/genética , Fibrosarcoma/inmunología , Melanoma Experimental/inmunología , Secuencia de Aminoácidos , Animales , Autoantígenos/inmunología , Progresión de la Enfermedad , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Fibrosarcoma/genética , Fibrosarcoma/patología , Melanoma Experimental/genética , Melanoma Experimental/patología , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones SCID , Datos de Secuencia Molecular , Oxidorreductasas/genética , Oxidorreductasas/inmunología , Linfocitos T/inmunología , Transfección

RESUMEN

Vaccines are often inefficient in old people and old mice. Few studies have focused on testing vaccines in old populations. Here we used DNA tumor antigen vaccines against melanoma and showed that old mice were not protected. Vaccines incorporating fusions of the tumor antigen with microbial adjuvant proteins OmpA (E. Coli) or Vp22 (Herpes simplex virus-1) dramatically improved protection of old mice. The mechanisms by which these adjuvant proteins act are distinct. TLR2 was not required for either OmpA or Vp22. Antigen processing and presentation were not boosted by these fusion constructs. However, fusion constructs with Vp22 gave a strong CD4 response to B16 melanoma and the OmpA response is MHC-II dependent. Both adjuvant fusion constructs stimulated CD4 and CD8 responses otherwise diminished in old mice.

Asunto(s)

Antígenos de Neoplasias/inmunología , Proteínas de la Membrana Bacteriana Externa/inmunología , Vacunas contra el Cáncer/inmunología , Melanoma/prevención & control , Proteínas Recombinantes de Fusión/farmacología , Vacunas de ADN/inmunología , Proteínas Estructurales Virales/farmacología , Adyuvantes Inmunológicos/genética , Adyuvantes Inmunológicos/farmacología , Animales , Antígenos de Neoplasias/genética , Proteínas de la Membrana Bacteriana Externa/genética , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Femenino , Interferón gamma/metabolismo , Melanoma/inmunología , Ratones , Ratones Endogámicos C57BL , Proteínas Recombinantes de Fusión/genética , Vacunas de ADN/genética , Proteínas Estructurales Virales/genética

RESUMEN

Granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances immune responses by inducing proliferation, maturation, and migration of dendritic cells (DCs) as well as expansion and differentiation of B and T lymphocytes. The potency of DNA vaccines can be enhanced by the addition of DNA encoding cytokines, acting as molecular adjuvants. We conducted a phase I/II trial of human GM-CSF DNA in conjunction with a multipeptide vaccine (gp100 and tyrosinase) in stage III/IV melanoma patients. Nineteen human leukocyte antigen (HLA)-A*0201+ patients were treated. Three dose levels were studied: 100, 400, and 800 microg DNA/injection, administered subcutaneously every month with 500 microg of each peptide. In the dose-ranging study, three patients were treated at each dose level. The remaining patients were then treated at the highest dose. Most toxicities were grade 1 injection-site reactions. Eight patients (42%) developed CD8+ T-cell responses, defined by a > or =3 SD increase in baseline reactivity to tyrosinase or gp100 peptide in tetramer or intracellular cytokine staining (ICS) assays. There was no relationship between dose and T-cell response. Responding T cells had an effector memory cell phenotype. Polyfunctional T cells were also demonstrated. At a median of 31 months follow-up, median survival has not been reached. Human GM-CSF DNA was found to be a safe adjuvant.

Asunto(s)

Adyuvantes Inmunológicos/metabolismo , Vacunas contra el Cáncer/inmunología , Terapia Genética , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Melanoma/inmunología , Melanoma/terapia , Vacunas de ADN/inmunología , Adyuvantes Inmunológicos/genética , Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer/efectos adversos , Vacunas contra el Cáncer/genética , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Humanos , Melanoma/patología , Estadificación de Neoplasias , Péptidos/efectos adversos , Péptidos/inmunología , Fenotipo , Proteínas Recombinantes , Vacunas de ADN/efectos adversos , Vacunas de ADN/genética , Vacunas de Subunidad/efectos adversos , Vacunas de Subunidad/inmunología

RESUMEN

Successful approaches to tumor immunotherapy must overcome the physiological state of tolerance of the immune system to self-tumor antigens. Immunization with appropriate variants of syngeneic antigens can achieve this. However, improvements in vaccine design are needed for efficient cancer immunotherapy. Here we explore nine different chimeric vaccine designs, in which the antigen of interest is expressed as an in-frame fusion with polypeptides that impact antigen processing or presentation. In DNA immunization experiments in mice, three of nine fusions elevated relevant CD8(+) T-cell responses and tumor protection relative to an unfused melanoma antigen. These fusions were: Escherichia coli outer membrane protein A (OmpA), Pseudomonas aeruginosa exotoxin A, and VP22 protein of herpes simplex virus-1. The gains of immunogenicity conferred by the latter two are independent of epitope presentation by major histocompatibility complex class II (MHC II). This finding has positive implications for immunotherapy in individuals with CD4(+) T-cell deficiencies. We present evidence that antigen instability is not a sine qua non condition for immunogenicity. Experiments using two additional melanoma antigens identified different optimal fusion partners, thereby indicating that the benefits of fusion vectors remain antigen specific. Therefore large fusion vector panels such as those presented here can provide information to promote the successful advancement of gene-based vaccines.

Asunto(s)

Antígenos de Neoplasias/inmunología , Vacunas contra el Cáncer/inmunología , Proteínas Recombinantes de Fusión/inmunología , Vacunas de ADN/inmunología , ADP Ribosa Transferasas/genética , ADP Ribosa Transferasas/inmunología , Animales , Presentación de Antígeno , Antígenos de Neoplasias/genética , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/inmunología , Toxinas Bacterianas/genética , Toxinas Bacterianas/inmunología , Linfocitos T CD8-positivos/inmunología , Células COS , Vacunas contra el Cáncer/genética , Vacunas contra el Cáncer/uso terapéutico , Chlorocebus aethiops , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/inmunología , Exotoxinas/genética , Exotoxinas/inmunología , Femenino , Antígenos de Histocompatibilidad Clase II/inmunología , Humanos , Melanoma Experimental/inmunología , Melanoma Experimental/terapia , Ratones , Ratones Endogámicos C57BL , Proteínas Recombinantes de Fusión/genética , Vacunación , Vacunas de ADN/genética , Vacunas de ADN/uso terapéutico , Proteínas Estructurales Virales/genética , Proteínas Estructurales Virales/inmunología , Factores de Virulencia/genética , Factores de Virulencia/inmunología , Exotoxina A de Pseudomonas aeruginosa

RESUMEN

One strategy to generate T-cell responses to tumors is to alter subdominant epitopes through substitution of amino acids that are optimal anchors for specific MHC molecules, termed heteroclitic epitopes. This approach is manually error-prone and time-consuming. In here, we describe a computer-based algorithm (EpitOptimizer) for the streamlined design of heteroclitic epitopes. Analysis of two cancer-related proteins showed that EpitOptimizer-generated peptides have enhanced MHC-I binding compared with their wild-type counterparts; and were able to induce stronger CD8+ T-cell responses against their native epitope. These data demonstrate that this approach can serve as the basis of epitope-engineering against cancer and intracellular pathogens.

Asunto(s)

Vacunas contra el Cáncer/inmunología , Biología Computacional/métodos , Epítopos/inmunología , Péptidos/inmunología , Algoritmos , Secuencia de Aminoácidos , Animales , Linfocitos T CD8-positivos/inmunología , Vacunas contra el Cáncer/genética , Vacunas contra el Cáncer/metabolismo , Reacciones Cruzadas , Epítopos/química , Epítopos/genética , Epítopos/metabolismo , Femenino , Antígenos de Histocompatibilidad Clase I/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Animales , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Neoplasias , Péptidos/química , Péptidos/genética , Péptidos/metabolismo , Ingeniería de Proteínas

RESUMEN

Malignant relapse remains a major problem for recipients of allogeneic hemopoietic stem cell transplantation (HSCT). We hypothesized that immunization of allogeneic HSCT recipients against tissue-restricted Ags using DNA vaccines would decrease the risk of relapse without enhancing graft-vs-host disease (GVHD). Using the mouse B16 melanoma model, we found that post-HSCT DNA immunization against a single tumor Ag induces tumor rejection that is significantly greater than HSCT alone in a T cell-depleted MHC-matched minor Ag-mismatched allogeneic HSCT model (LP --> B6). In treatment models, post-HSCT DNA immunization provides significantly greater overall survival than the vaccine alone. Donor leukocyte infusion further enhances tumor-free survival, including in treatment models. There was no GVHD in HSCT recipients treated with DNA vaccination and donor leukocyte infusion. Further analysis demonstrated that these effects are dependent on CD8+ T cells of donor origin that recognize multiple epitopes. These results demonstrate that DNA immunization against tissue-restricted Ags after allogeneic T cell-depleted HSCT can induce potent antitumor effects without causing GVHD.

Asunto(s)

Antígenos de Neoplasias/inmunología , Trasplante de Células Madre Hematopoyéticas , Melanoma Experimental/inmunología , Melanoma Experimental/prevención & control , Vacunas de ADN/inmunología , Animales , Trasplante de Médula Ósea/inmunología , Línea Celular Tumoral , Femenino , Rechazo de Injerto/inmunología , Enfermedad Injerto contra Huésped/inmunología , Enfermedad Injerto contra Huésped/prevención & control , Transfusión de Leucocitos , Melanoma Experimental/terapia , Ratones , Ratones Endogámicos C57BL , Especificidad de Órganos/inmunología , Linfocitos T/inmunología , Trasplante Homólogo , Vacunas de ADN/administración & dosificación

RESUMEN

A relationship between melanoma and vitiligo, a skin disorder characterized by the loss of melanocytes, has been postulated for many decades. In some cases, vitiligo is almost certainly a manifestation of autoimmune-mediated destruction of melanocytes. Melanocytes and melanoma cells share melanocyte differentiation antigens. Based on a number of observations, de novo vitiligo developing in patients with melanoma has been regarded as a sign of good prognosis. The immune system tolerates or ignores differentiation antigens because these antigens are self-derived. Therefore, immune tolerance or ignorance must be overcome to prime naive T and B cells to induce cancer immunity and autoimmunity against melanocyte differentiation antigens. Mouse models of concurrent melanoma and autoimmune vitiligo have revealed strategies to overcome immune ignorance or tolerance to melanocyte differentiation antigens: immunization with self-antigens as altered self (e.g., orthologues or mutated versions), expression in viral vectors, passive immunization with antibodies or T cells, incorporating potent adjuvants into active immunization, and blockade or removal of a downregulatory mechanism. Extensive investigations into the mechanisms that lead to tumor immunity and autoimmunity elicited by certain differentiation antigens have further revealed a variety of distinct cellular and molecular requirements, which are redundant and alternative.

Asunto(s)

Enfermedades Autoinmunes/inmunología , Melanoma/inmunología , Vitíligo/inmunología , Animales , Antígenos de Diferenciación/administración & dosificación , Antígenos de Diferenciación/inmunología , Antígenos de Diferenciación/uso terapéutico , Autoanticuerpos/biosíntesis , Autoantígenos/administración & dosificación , Autoantígenos/inmunología , Autoantígenos/uso terapéutico , Enfermedades Autoinmunes/patología , Enfermedades Autoinmunes/prevención & control , Humanos , Melanoma/diagnóstico , Melanoma/patología , Vacunación/métodos , Vacunación/tendencias , Vitíligo/diagnóstico , Vitíligo/patología

RESUMEN

T cells recognizing self antigens expressed by cancer cells are prevalent in the immune repertoire. However, activation of these autoreactive T cells is limited by weak signals that are incapable of fully priming naive T cells, creating a state of tolerance or ignorance. Even if T cell activation occurs, immunity can be further restricted by a dominant response directed at only a single epitope. Enhanced antigen presentation of multiple epitopes was investigated as a strategy to overcome these barriers. Specific point mutations that create altered peptide ligands were introduced into the gene encoding a nonimmunogenic tissue self antigen expressed by melanoma, tyrosinase-related protein-1 (Tyrp1). Deficient asparagine-linked glycosylation, which was caused by additional mutations, produced altered protein trafficking and fate that increased antigen processing. Immunization of mice with mutated Tyrp1 DNA elicited cross-reactive CD8(+) T cell responses against multiple nonmutated epitopes of syngeneic Tyrp1 and against melanoma cells. These multi-specific anti-Tyrp1 CD8(+) T cell responses led to rejection of poorly immunogenic melanoma and prolonged survival when immunization was started after tumor challenge. These studies demonstrate how rationally designed DNA vaccines directed against self antigens for enhanced antigen processing and presentation reveal novel self epitopes and elicit multi-specific T cell responses to nonimmunogenic, nonmutated self antigens, enhancing immunity against cancer self antigens.

Asunto(s)

Autoantígenos/química , Epítopos/química , Neoplasias/inmunología , Animales , Presentación de Antígeno , Asparagina/química , Linfocitos T CD8-positivos/metabolismo , Femenino , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Oxidorreductasas/química , Oxidorreductasas/genética , Linfocitos T/inmunología

RESUMEN

Little is known about the consequences of immune recognition of mutated gene products, despite their potential relevance to autoimmunity and tumor immunity. To identify mutations that induce immunity, here we have developed a systematic approach in which combinatorial DNA libraries encoding large numbers of random mutations in two syngeneic tyrosinase-related proteins are used to immunize black mice. We show that the libraries of mutated DNA induce autoimmune hypopigmentation and tumor immunity through cross-recognition of nonmutated gene products. Truncations are present in all immunogenic clones and are sufficient to elicit immunity to self, triggering recognition of normally silent epitopes. Immunity is further enhanced by specific amino acid substitutions that promote T helper cell responses. Thus, presentation of a vast repertoire of antigen variants to the immune system can enhance the generation of adaptive immune responses to self.

Asunto(s)

Autoantígenos/genética , Autoinmunidad/genética , Mutación , Neoplasias Experimentales/genética , Neoplasias Experimentales/inmunología , Secuencia de Aminoácidos , Animales , Antígenos de Neoplasias/genética , Secuencia de Bases , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Células COS , Chlorocebus aethiops , Reacciones Cruzadas , ADN Complementario/genética , Biblioteca de Genes , Oxidorreductasas Intramoleculares/genética , Oxidorreductasas Intramoleculares/inmunología , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Autotolerancia/genética , Transfección

RESUMEN

Around 700 BCE, a new military formation called the phalanx was established in ancient Greece: a tight column of heavy infantry carrying long spears, or pikes, used in a single prong of attack. Later, in the battle of Marathon described by Herodotus, the Greeks learned the advantages of multipronged attacks, a strategy still used in modern warfare. Is the immune system similar in its approach to combatting pathogens or tumors?

Asunto(s)

Linfocitos T CD8-positivos/inmunología , Infecciones por Citomegalovirus/inmunología , Inmunidad Celular , Neoplasias/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Antígenos CD , Antígenos de Diferenciación/inmunología , Antígeno CTLA-4 , Humanos , Proteínas Inmediatas-Precoces/inmunología , Fosfoproteínas/inmunología , Proteínas de la Matriz Viral/inmunología , Proteínas Virales/inmunología

RESUMEN

Concomitant tumor immunity describes immune responses in a host with a progressive tumor that rejects the same tumor at a remote site. In this work, concomitant tumor immunity was investigated in mice bearing poorly immunogenic B16 melanoma. Progression of B16 tumors did not spontaneously elicit concomitant immunity. However, depletion of CD4(+) T cells in tumor-bearing mice resulted in CD8(+) T cell-mediated rejection of challenge tumors given on day 6. Concomitant immunity was also elicited by treatment with cyclophosphamide or DTA-1 monoclonal antibody against the glucocorticoid-induced tumor necrosis factor receptor. Immunity elicited by B16 melanoma cross-reacted with a distinct syngeneic melanoma, but not with nonmelanoma tumors. Furthermore, CD8(+) T cells from mice with concomitant immunity specifically responded to major histocompatibility complex class I-restricted epitopes of two melanocyte differentiation antigens. RAG1(-/-) mice adoptively transferred with CD8(+) and CD4(+) T cells lacking the CD4(+)CD25(+) compartment mounted robust concomitant immunity, which was suppressed by readdition of CD4(+)CD25(+) cells. Naturally occurring CD4(+)CD25(+) T cells efficiently suppressed concomitant immunity mediated by previously activated CD8(+) T cells, demonstrating that precursor regulatory T cells in naive hosts give rise to effective suppressors. These results show that regulatory T cells are the major regulators of concomitant tumor immunity against this weakly immunogenic tumor.

Asunto(s)

Melanoma Experimental/inmunología , Linfocitos T/inmunología , Traslado Adoptivo , Animales , Antígenos de Diferenciación/inmunología , Ciclofosfamida/farmacología , Genes RAG-1 , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Interleucina-10/fisiología , Ratones , Ratones Endogámicos C57BL , Receptores de Interleucina-2/análisis

RESUMEN

Successful active immunization against cancer requires induction of immunity against self or mutated self Ags. However, immunization against self Ags is difficult. Xenogeneic immunization with orthologous Ags induces cancer immunity. The present study evaluated the basis for immunity induced by active immunization against a melanoma differentiation Ag, gp100. Tumor rejection of melanoma was assessed after immunization with human gp100 (hgp100) DNA compared with mouse gp100 (mgp100). C57BL/6 mice immunized with xenogeneic full-length hgp100 DNA were protected against syngeneic melanoma challenge. In contrast, mice immunized with hgp100 DNA and given i.p. tolerizing doses of the hgp100 D(b)-restricted peptide, hgp100(25-33), were incapable of rejecting tumors. Furthermore, mice immunized with DNA constructs of hgp100 in which the hgp100(25-27) epitope was substituted with the weaker D(b)-binding epitope from mgp100 (mgp100(25-27)) or a mutated epitope unable to bind D(b) did not reject B16 melanoma. Mice immunized with a minigene construct of hgp100(25-33) rejected B16 melanoma, whereas mice immunized with the mgp100(25-33) minigene did not develop protective tumor immunity. In this model of xenogeneic DNA immunization, the presence of an hgp100 heteroclitic epitope with a higher affinity for MHC created by three amino acid (25 to 27) substitutions at predicted minor anchor residues was necessary and sufficient to induce protective tumor immunity in H-2(b) mice with melanoma.

Asunto(s)

Antígenos Heterófilos/inmunología , Vacunas contra el Cáncer/inmunología , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Melanoma Experimental/inmunología , Glicoproteínas de Membrana/inmunología , Proteínas de Neoplasias/inmunología , Vacunas de ADN/inmunología , Secuencia de Aminoácidos , Sustitución de Aminoácidos/genética , Sustitución de Aminoácidos/inmunología , Animales , Antígenos Heterófilos/administración & dosificación , Antígenos Heterófilos/genética , Antígenos Heterófilos/metabolismo , Asparagina/genética , Linfocitos T CD4-Positivos/inmunología , Vacunas contra el Cáncer/administración & dosificación , Vacunas contra el Cáncer/genética , Vacunas contra el Cáncer/metabolismo , Citotoxicidad Inmunológica/genética , Relación Dosis-Respuesta Inmunológica , Epítopos de Linfocito T/metabolismo , Femenino , Genes Relacionados con las Neoplasias/inmunología , Antígenos H-2/metabolismo , Antígeno de Histocompatibilidad H-2D , Humanos , Inyecciones Intraperitoneales , Melanoma Experimental/genética , Melanoma Experimental/prevención & control , Glicoproteínas de Membrana/administración & dosificación , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Proteínas de Neoplasias/administración & dosificación , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/inmunología , Fragmentos de Péptidos/metabolismo , Unión Proteica/genética , Unión Proteica/inmunología , Triptófano/genética , Células Tumorales Cultivadas , Vacunas de ADN/administración & dosificación , Vacunas de ADN/genética , Vacunas de ADN/metabolismo , Antígeno gp100 del Melanoma

RESUMEN

PURPOSE: Canine malignant melanoma (CMM) is a spontaneous, aggressive, and metastatic neoplasm. Preclinical mouse studies have shown that xenogeneic DNA vaccination with genes encoding tyrosinase family members can induce antibody and cytotoxic T-cell responses, resulting in tumor rejection. These studies provided the rationale for a trial of xenogeneic DNA vaccination in CMM using the human tyrosinase gene. EXPERIMENTAL DESIGN: Three cohorts of three dogs each with advanced (WHO stage II, III, or IV) CMM received four biweekly i.m. injections (dose levels 100, 500, or 1500 micro g, respectively/vaccination) of human tyrosinase plasmid DNA i.m. via the Biojector2000 delivery device. RESULTS: Mild local reactions at injection sites were the only toxicities observed, with no signs of autoimmunity. One dog with stage IV disease had a complete clinical response in multiple lung metastases for 329 days. Two dogs with stage IV disease had long-term survivals (421 and 588+ days) in the face of significant bulky metastatic disease, and two other dogs with locally controlled stage II/III disease had long-term survivals (501 and 496 days) with no evidence of melanoma on necropsy. Four other dogs were euthanized because of progression of the primary tumor. The Kaplan-Meier median survival time for all nine dogs was 389 days. CONCLUSIONS: The results of this trial demonstrate that xenogeneic DNA vaccination of dogs with advanced malignant melanoma is a safe and potentially therapeutic modality. On the basis of these results, additional evaluation of this novel therapeutic is warranted in locally controlled CMM and advanced human melanoma.

Asunto(s)

Vacunas contra el Cáncer/uso terapéutico , Melanoma/terapia , Vacunas de ADN/uso terapéutico , Animales , Estudios de Cohortes , ADN Complementario/metabolismo , Perros , Femenino , Humanos , Inmunoterapia/métodos , Masculino , Melanoma/mortalidad , Monofenol Monooxigenasa/genética , Plásmidos/metabolismo , Radiografía Torácica , Factores de Tiempo

RESUMEN

Cancer poses a difficult problem for immunotherapy because it arises from the host's own tissues. Many of the target antigens are tissue-specific molecules shared by cancer cells and normal cells. Thus, these are weak antigens that do not typically elicit immunity. In addition, tumors have several features that make their recognition and destruction by the immune system difficult. Despite these obstacles, several strategies for developing effective tumor immunity have been developed. Crucial to these approaches is the discovery and understanding of the molecular identity of antigens and the mechanisms involved in tumor immunity. In this review, strategies to overcome immune ignorance and tolerance are discussed.

Asunto(s)

Tolerancia Inmunológica , Neoplasias/inmunología , Antígenos de Neoplasias/inmunología , Humanos