I2CT

@article{flacher_murine_2014,

title = {Murine Langerin+ dermal dendritic cells prime CD8+ Ŧ cells while Langerhans cells induce cross-tolerance},

author = {Vincent Flacher and Christoph H Tripp and David G Mairhofer and Ralph M Steinman and Patrizia Stoitzner and Juliana Idoyaga and Nikolaus Romani},

doi = {10.15252/emmm.201303283},

issn = {1757-4684},

year  = {2014},

date = {2014-09-01},

journal = {EMBO molecular medicine},

volume = {6},

number = {9},

pages = {1191--1204},

abstract = {Skin dendritic cells (DCs) control the immunogenicity of cutaneously administered vaccines. Antigens targeted to DCs via the C-type lectin Langerin/CD207 are cross-presented to CD8(+) T cells in vivo. We investigated the relative roles of Langerhans cells (LCs) and Langerin(+) dermal DCs (dDCs) in different vaccination settings. Poly(I:C) and anti-CD40 agonist antibody promoted cytotoxic responses upon intradermal immunization with ovalbumin (OVA)-coupled anti-Langerin antibodies (Langerin/OVA). This correlated with CD70 upregulation in Langerin(+) dDCs, but not LCs. In chimeric mice where Langerin targeting was restricted to dDCs, CD8(+) T-cell memory was enhanced. Conversely, providing Langerin/OVA exclusively to LCs failed to prime cytotoxicity, despite initial antigen cross-presentation to CD8(+) T cells. Langerin/OVA combined with imiquimod could not prime CD8(+) T cells and resulted in poor cytotoxicity in subsequent responses. This tolerance induction required targeting and maturation of LCs. Altogether, Langerin(+) dDCs prime long-lasting cytotoxic responses, while cross-presentation by LCs negatively influences CD8(+) T-cell priming. Moreover, this highlights that DCs exposed to TLR agonists can still induce tolerance and supports the existence of qualitatively different DC maturation programs.},

keywords = {agonists, Animals, Antibodies, antibody, Antigen, Antigen Presentation, Antigens, C-Type, C-type lectin, cancer, CD70, CD8-Positive T-Lymphocytes, CD8+ T cells, CD8+ T‐cell responses, Cellular, CROSS-PRESENTATION, Cross-Priming, Cytotoxicity, Dendritic Cells, DERMAL DENDRITIC CELLS, DERMATOLOGY, disease, imiquimod, Immunization, IMMUNOGENICITY, Immunologic Memory, Immunological, Immunology, In vivo, Inbred C57BL, INDUCTION, Intradermal, Langerhans Cells, LECTIN, Lectins, Mannose-Binding Lectins, Maturation, Mice, Models, murine, OVALBUMIN, physiology, priming, RESPONSES, Skin, Surface, T CELLS, T-CELLS, Team-Mueller, tolerance, Vaccination, vaccine, Vaccines},

pubstate = {published},

tppubtype = {article}

}

@article{flacher_targeting_2009,

title = {Targeting of epidermal Langerhans cells with antigenic proteins: attempts to harness their properties for immunotherapy},

author = {Vincent Flacher and Florian Sparber and Christoph H Tripp and Nikolaus Romani and Patrizia Stoitzner},

doi = {10.1007/s00262-008-0563-9},

issn = {1432-0851},

year  = {2009},

date = {2009-07-01},

journal = {Cancer immunology, immunotherapy: CII},

volume = {58},

number = {7},

pages = {1137--1147},

abstract = {Langerhans cells, a subset of skin dendritic cells in the epidermis, survey peripheral tissue for invading pathogens. In recent functional studies it was proven that Langerhans cells can present exogenous antigen not merely on major histocompatibility complexes (MHC)-class II molecules to CD4+ T cells, but also on MHC-class I molecules to CD8+ T cells. Immune responses against topically applied antigen could be measured in skin-draining lymph nodes. Skin barrier disruption or co-application of adjuvants was required for maximal induction of T cell responses. Cytotoxic T cells induced by topically applied antigen inhibited tumor growth in vivo, thus underlining the potential of Langerhans cells for immunotherapy. Here we review recent work and report novel observations relating to the potential use of Langerhans cells for immunotherapy. We investigated the potential of epicutaneous immunization strategies in which resident skin dendritic cells are loaded with tumor antigen in situ. This contrasts with current clinical approaches, where dendritic cells generated from progenitors in blood are loaded with tumor antigen ex vivo before injection into cancer patients. In the current study, we applied either fluorescently labeled protein antigen or targeting antibodies against DEC-205/CD205 and langerin/CD207 topically onto barrier-disrupted skin and examined antigen capture and transport by Langerhans cells. Protein antigen could be detected in Langerhans cells in situ, and they were the main skin dendritic cell subset transporting antigen during emigration from skin explants. Potent in vivo proliferative responses of CD4+ and CD8+ T cells were measured after epicutaneous immunization with low amounts of protein antigen. Targeting antibodies were mainly transported by langerin+ migratory dendritic cells of which the majority represented migratory Langerhans cells and a smaller subset the new langerin+ dermal dendritic cell population located in the upper dermis. The preferential capture of topically applied antigen by Langerhans cells and their ability to induce potent CD4+ and CD8+ T cell responses emphasizes their potential for epicutaneous immunization strategies.},

keywords = {Active, Animals, Antibodies, antibody, Antigen, Antigens, BLOOD, C-Type, cancer, CD, CD4-Positive T-Lymphocytes, CD4+ T cells, CD8-Positive T-Lymphocytes, CD8+ T cells, Dendritic Cells, DERMATOLOGY, DERMIS, Epidermis, Growth, Human, Humans, immune response, IMMUNE-RESPONSES, Immunization, Immunology, Immunotherapy, in situ, In vivo, Inbred BALB C, Inbred C57BL, INDUCTION, Langerhans Cells, LECTIN, Lectins, LYMPH, LYMPH NODE, Lymph Nodes, Major Histocompatibility Complex, Mannose-Binding Lectins, metabolism, methods, MHC class I, MHC class I molecules, Mice, Neoplasm, Neoplasms, OVALBUMIN, Patients, PROGENITORS, Protein, Proteins, RESPONSES, review, Skin, T CELLS, T-CELLS, Team-Mueller, therapy, tumor},

pubstate = {published},

tppubtype = {article}

}