RESUMO
The endothelial glycoprotein MUC1 is known to underlie alterations in cancer by means of aberrant glycosylation accompanied by changes in morphology. The heavily shortened glycans induce a collapse of the peptide backbone and enable accessibility of the latter to immune cells, rendering it a tumor-associated antigen. Synthetic vaccines based on MUC1 tandem repeat motifs, comprising tumor-associated 2,3-sialyl-T antigen, conjugated to the immunostimulating tetanus toxoid, are reported herein. Immunization with these vaccines in a simple water/oil emulsion produced a strong immune response in mice to which stimulation with complete Freund's adjuvant (CFA) was not superior. In both cases, high levels of IgG1 and IgG2a/b were induced in C57BL/6 mice. Additional glycosylation in the immunodominant PDTRP domain led to improved binding of the induced antisera to MCF-7 breast tumor cells, compared with that of the monoglycosylated peptide vaccine.
RESUMO
A MUC1 anticancer vaccine equipped with covalently linked divalent mannose ligands was found to improve the antigen uptake and presentation by targeting mannose-receptor-positive macrophages and dendritic cells. It induced much stronger specific IgG immune responses in mice than the non-mannosylated reference vaccine. Mannose coupling also led to increased numbers of macrophages, dendritic cells, and CD4+ T cells in the local lymph organs. Comparison of di- and tetravalent mannose ligands revealed an increased binding of the tetravalent version, suggesting that higher valency improves binding to the mannose receptor. The mannose-coupled vaccine and the non-mannosylated reference vaccine induced IgG antibodies that exhibited similar binding to human breast tumor cells.
Assuntos
Vacinas Anticâncer/imunologia , Células Dendríticas/metabolismo , Macrófagos/metabolismo , Manose/química , Mucina-1/imunologia , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Vacinas Anticâncer/metabolismo , Células Dendríticas/citologia , Células Dendríticas/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina G/análise , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Lectinas Tipo C/metabolismo , Ligantes , Linfonodos , Células MCF-7 , Macrófagos/citologia , Macrófagos/imunologia , Receptor de Manose , Lectinas de Ligação a Manose/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Mucina-1/química , Mucina-1/metabolismo , Ligação Proteica , Receptores de Superfície Celular/metabolismoRESUMO
Breaking tolerance is crucial for effective tumor immunotherapy. We showed that vaccines containing tumor-associated human MUC1 glycopeptides induce strong humoral antitumor responses in mice. The question remained whether such vaccines work in humans, in systems where huMUC1 is a self-antigen. To clarify the question, mice transgenic in expressing huMUC1, mimicking the self-tolerant environment, and wild-type mice were vaccinated with a synthetic vaccine. This vaccine comprised STn and Tn antigens bound to a MUC1 tandem repeat peptide coupled to tetanus toxoid. The vaccine induced strong immune responses in wild-type and huMUC1-transgenic mice without auto-aggressive side effects. All antisera exhibited almost equivalent binding to human breast tumor cells. Similar increases of activated B-, CD4+ T-, and dendritic cells was found in the lymph nodes. The results demonstrate that tumor-associated huMUC1 glycopeptides coupled to tetanus toxoid are promising antitumor vaccines.
Assuntos
Antígenos Glicosídicos Associados a Tumores/uso terapêutico , Neoplasias da Mama/prevenção & controle , Vacinas Anticâncer/uso terapêutico , Mucina-1/uso terapêutico , Fragmentos de Peptídeos/uso terapêutico , Toxoide Tetânico/uso terapêutico , Vacinas Sintéticas/uso terapêutico , Animais , Antígenos Glicosídicos Associados a Tumores/química , Antígenos Glicosídicos Associados a Tumores/imunologia , Neoplasias da Mama/imunologia , Vacinas Anticâncer/química , Vacinas Anticâncer/imunologia , Feminino , Humanos , Imunização , Células MCF-7 , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mucina-1/química , Fragmentos de Peptídeos/química , Toxoide Tetânico/química , Toxoide Tetânico/imunologia , Vacinas Sintéticas/química , Vacinas Sintéticas/imunologiaRESUMO
Fully synthetic MUC1 glycopeptide antitumor vaccines have a precisely specified structure and induce a targeted immune response without suppression of the immune response when using an immunogenic carrier protein. However, tumor-associated aberrantly glycosylated MUC1 glycopeptides are endogenous structures, "self-antigens", that exhibit only low immunogenicity. To overcome this obstacle, a fully synthetic MUC1 glycopeptide antitumor vaccine was combined with poly(inosinic acid:cytidylic acid), poly(I:C), as a structurally defined Toll-like receptorâ 3 (TLR3)-activating adjuvant. This vaccine preparation elicited extraordinary titers of IgG antibodies which strongly bound human breast cancer cells expressing tumor-associated MUC1. Beside the humoral response, the poly(I:C) glycopeptide vaccine induced a pro-inflammatory environment, very important to overcome the immune-suppressive mechanisms, and elicited a strong cellular immune response crucial for tumor elimination.
Assuntos
Vacinas Anticâncer/imunologia , Glicopeptídeos/imunologia , Mucina-1/imunologia , Poli I-C/imunologia , Receptor 3 Toll-Like/imunologia , Vacinas Sintéticas/imunologia , Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/genética , Adjuvantes Imunológicos/farmacologia , Animais , Vacinas Anticâncer/genética , Vacinas Anticâncer/farmacologia , Células Dendríticas , Humanos , Camundongos , Poli I-C/química , Vacinas Sintéticas/genética , Vacinas Sintéticas/farmacologiaRESUMO
Self-adjuvanting antitumor vaccines by multifunctional cationic nanohydrogels loaded with CpG. A conjugate consisting of tumor-associated MUC1-glycopeptide B-cell epitope and tetanus toxin T-cell epitope P2 is linked to cationic nanogels. Oligonucleotide CpG complexation enhances toll-like receptor (TLR) stimulated T-cell proliferation and rapid immune activation. This co-delivery promotes induction of specific MUC1-antibodies binding to human breast tumor cells without external adjuvant.
Assuntos
Adjuvantes Imunológicos/farmacologia , Vacinas Anticâncer/imunologia , Glicopeptídeos/imunologia , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Nanopartículas/química , Oligodesoxirribonucleotídeos/química , Sequência de Aminoácidos , Animais , Cátions , Ensaio de Imunoadsorção Enzimática , Glicopeptídeos/química , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/síntese química , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Nanopartículas/ultraestruturaRESUMO
In a new concept of fully synthetic vaccines, the role of T-helper cells is emphasized. Here, a synthetic antitumor vaccine consisting of a diglycosylated tumor-associated MUC1 glycopeptide as the B-cell epitope was covalently cross-linked with three different T-helper-cell epitopes via squaric acid ligation of two linear (glyco)peptides. In mice this four-component vaccine administered without external immune-stimulating promoters elicit titers of MUC1-specific antibodies that were about eight times higher than those induced by a vaccine containing only one T-helper-cell epitope. The promising results indicate that multiple activation of different T-helper cells is useful for applications in which increased immunogenicity is required. In personalized medicine, in particular, this flexible construction of a vaccine can serve as a role model, for example, when T-helper-cell epitopes are needed that match human leukocyte antigens (HLA) in different patients.
Assuntos
Antígenos de Neoplasias/química , Vacinas Anticâncer/síntese química , Epitopos/química , Glicopeptídeos/química , Mucina-1/química , Linfócitos T Auxiliares-Indutores/química , Reações Antígeno-Anticorpo , Antígenos de Neoplasias/imunologia , Vacinas Anticâncer/química , Vacinas Anticâncer/imunologia , Epitopos/imunologia , Glicopeptídeos/imunologia , Humanos , Estrutura Molecular , Mucina-1/imunologia , Linfócitos T Auxiliares-Indutores/imunologiaRESUMO
For antitumor vaccines both the selected tumor-associated antigen, as well as the mode of its presentation, affect the immune response. According to the principle of multiple antigen presentation, a tumor-associated MUC1 glycopeptide combined with the immunostimulating T-cell epitope P2 from tetanus toxoid was coupled to a multi-functionalized hyperbranched polyglycerol by "click chemistry". This globular polymeric carrier has a flexible dendrimer-like structure, which allows optimal antigen presentation to the immune system. The resulting fully synthetic vaccine induced strong immune responses in mice and IgG antibodies recognizing human breast-cancer cells.