The role of the e3 ligase cbl-B in murine dendritic cells

• Published in: PloS one 2013-06, Vol.8 (6), p.e65178-e65178
• Main Authors: Wallner, Stephanie, Lutz-Nicoladoni, Christina, Tripp, Christoph H, Gastl, Günther, Baier, Gottfried, Penninger, Josef M, Stoitzner, Patrizia, Wolf, Dominik
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - deficiency; Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - immunology; Amino acids; Animals; Antigen presentation; Antigen-presenting cells; Antigens; Antigens, CD - genetics; Antigens, CD - immunology; Apoptosis; Biological Transport; Biology; Bone marrow; Bone Marrow Cells - cytology; Bone Marrow Cells - drug effects; Bone Marrow Cells - immunology; Cancer; Cancer immunotherapy; Cbl protein; Cbl-b protein; CD4 antigen; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - immunology; CD8 antigen; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; Cell activation; Cell Differentiation; CpG islands; Cytokines; Cytokines - biosynthesis; Cytokines - immunology; Dendritic cells; Dendritic Cells - cytology; Dendritic Cells - drug effects; Dendritic Cells - immunology; Dermatology; Dextran; Dextrans; Dextrans - metabolism; FDA approval; Fluorescein-5-isothiocyanate - analogs & derivatives; Fluorescein-5-isothiocyanate - metabolism; Gene Expression; Genetic engineering; Granulocytes; Hematology; Immune system; Immunology; Immunotherapy; Inflammation; Interleukin 6; Internal medicine; Laboratories; Lectins, C-Type - genetics; Lectins, C-Type - immunology; Leukocytes (mononuclear); Ligands; Ligases; Lipopolysaccharides; Lipopolysaccharides - pharmacology; Lymph nodes; Lymphocyte Culture Test, Mixed; Lymphocytes; Lymphocytes B; Lymphocytes T; Medical research; Medicine; Melanoma, Experimental - drug therapy; Melanoma, Experimental - immunology; Melanoma, Experimental - pathology; Mice; Mice, Knockout; Minor Histocompatibility Antigens; Oncology; Ovalbumin; Ovalbumin - immunology; Peptides; Peptides - pharmacology; Poly I-C - pharmacology; Polyinosinic:polycytidylic acid; Proteins; Proto-Oncogene Proteins c-cbl - deficiency; Proto-Oncogene Proteins c-cbl - genetics; Proto-Oncogene Proteins c-cbl - immunology; Receptors, Cell Surface - genetics; Receptors, Cell Surface - immunology; Skin Neoplasms - drug therapy; Skin Neoplasms - immunology; Skin Neoplasms - pathology; Studies; T cell receptors; T cells; Toll-like receptors; Tumor necrosis factor-α; Tumors; Ubiquitin; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - deficiency; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - immunology; Vaccines
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0065178

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.