title: The role of the e3 ligase cbl-B in murine dendritic cells.
abstract: Dendritic cells (DCs) are potent antigen-presenting cells with a promising potential in cancer immunotherapy. Cbl proteins are E3 ubiquitin ligases and have been implicated in regulating the functional activity of various immune cells. As an example, c-Cbl negatively affects DC activation. We here describe that another member of the Cbl-protein family (i.e. Cbl-b) is highly expressed in murine bone-marrow-derived DCs (BMDCs). Differentiation of cblb-/- bone marrow mononuclear cells into classical BMDCs is unaltered, except enhanced induction of DEC-205 (CD205) expression. When tested in mixed-lymphocyte reaction (MLR), cblb-/- BMDCs exhibit increased allo-stimulatory capacity in vitro. BMDCs were next in vitro stimulated by various toll like receptor (TLR)-agonists (LPS, Poly(I:C), CpG) and exposed to FITC-labeled dextran. Upon TLR-stimulation, cblb-/- BMDCs produce higher levels of proinflammatory cytokines (IL-1α, IL-6 and TNF-α) and exhibit a slightly higher level of FITC-dextran uptake. To further characterize the functional significance of cblb-/- BMDCs we tested them in antigen-specific T cell responses against ovalbumin (OVA) protein and peptides, activating either CD8(+) OT-I or CD4(+) OT-II transgenic T cells. However, cblb-/- BMDCs are equally effective in inducing antigen-specific T cell responses when compared to wildtype BMDCs both in vitro and in vivo. The migratory capacity into lymph nodes during inflammation was similarly not affected by the absence of Cbl-b. In line with these observations, cblb-/- peptide-pulsed BMDCs are equally effective vaccines against OVA-expressing B16 tumors in vivo when compared to wildtype BMDCs. We conclude that in contrast to c-Cbl, Cbl-b plays only a limited role in the induction of Ag-specific T cell responses by murine BMDCs in vitro and in vivo.
authors.affiliation: Laboratory of Tumor Immunology, Tyrolean Cancer Research Institute, Innsbruck, Austria.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Wallner
authors.forename: Christina
authors.initials: C
authors.lastname: Lutz-Nicoladoni
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Tripp
authors.forename: Günther
authors.initials: G
authors.lastname: Gastl
authors.forename: Gottfried
authors.initials: G
authors.lastname: Baier
authors.forename: Josef M
authors.initials: JM
authors.lastname: Penninger
authors.forename: Patrizia
authors.initials: P
authors.lastname: Stoitzner
authors.forename: Dominik
authors.initials: D
authors.lastname: Wolf
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology; D001692:Biological Transport; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D003911:Dextrans / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D015870:Gene Expression; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D007959:Lymphocyte Culture Test, Mixed; D008546:Melanoma, Experimental / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D015778:Minor Histocompatibility Antigens; D010047:Ovalbumin / Q000276:immunology; D010455:Peptides / Q000494:pharmacology; D011070:Poly I-C / Q000494:pharmacology; D050721:Proto-Oncogene Proteins c-cbl / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000276:immunology; D012878:Skin Neoplasms / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D044767:Ubiquitin-Protein Ligases / Q000172:deficiency / Q000235:genetics / Q000276:immunology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; C118387:Cblb protein, mouse; D016207:Cytokines; C093569:DEC-205 receptor; D003911:Dextrans; D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D015778:Minor Histocompatibility Antigens; D010455:Peptides; D011956:Receptors, Cell Surface; C015219:fluorescein isothiocyanate dextran; D010047:Ovalbumin; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D016650:Fluorescein-5-isothiocyanate; D011070:Poly I-C