Monocyte-derived dendritic cells from Crohn patients show differential NOD2/CARD15-dependent immune responses to bacteria.

Background: Three common mutations in the NOD2/CARD15 gene are strongly associated with Crohn's disease (CD). NOD2 is an intracellular receptor of muramyl dipeptide (MDP), a component of peptidoglycan present in the cell wall of gram-positive (G+) and gram-negative (G-) bacteria.

Methods: We generated monocyte-derived dendritic cells (MoDCs) from CD patients mutated or not for CARD15 (n = 53) or from healthy donors (n = 12) and analyzed their activation in response to live Salmonella typhimurium as a model of pathogenic G- bacteria.

Genetic vaccines against Ep-CAM break tolerance to self in a limited subset of subjects: initial identification of predictive biomarkers.

The epithelial cell adhesion molecule, Ep-CAM, has been historically considered a target of passive immunotherapy using monoclonal antibodies, and more recently, of a first Pox-vector-based cancer vaccine Phase I trial in colorectal cancer patients. To shed further light on the use of this antigen, we isolated the mouse and rhesus homologues of human Ep-CAM and explored different genetic vaccination modalities based on the use of adenoviral vectors as well as DNA electroporation (DNA-EP). Immune responses to Ep-CAM were measured by IFN-gamma ELISPOT and intracellular staining assays using overlapping sets of peptides covering the entire coding regions.

CD8+ T-cell tolerance can be broken by an adenoviral vaccine while CD4+ T-cell tolerance is broken by additional co-administration of a Toll-like receptor ligand.

T-cell tolerance to tumor antigens is a considerable challenge to cancer immunotherapy. The existence of a murine model transgenic for human carcinoembryonic antigen (CEA) allows CEA vaccination efficacy to be studied in a physiologically tolerant context. Immunization of CEA-transgenic mice with an adenoviral vector coding for CEA induced a significant CD8+ T-cell response specific to CEA but failed to induce CEA-specific CD4+ T cells and antibodies.

Adenovirus transduction and culture conditions affect the immunogenicity of murine dendritic cells.

Adenovirus vectors encoding carcinoembryonic antigen (Ad-CEA) or costimulatory molecules CD80, intercellular adhesion molecule-1 (ICAM-1) and leucocyte function-associated antigen-3 (LFA-3) (Ad-STIM) were used to transduce murine bone marrow-derived dendritic cells (BMDC). BMDC were characterized for expression of activation markers and for their ability to elicit protective immunity against MC38-CEA tumours in wildtype and CEA-transgenic (CEA-tg) mice. To determine optimal culture conditions, studies were conducted using BMDC cultured in heterologous bovine serum or autologous mouse serum.

Intestinal immune homeostasis is regulated by the crosstalk between epithelial cells and dendritic cells.

The control of damaging inflammation by the mucosal immune system in response to commensal and harmful ingested bacteria is unknown. Here we show epithelial cells conditioned mucosal dendritic cells through the constitutive release of thymic stromal lymphopoietin and other mediators, resulting in the induction of 'noninflammatory' dendritic cells. Epithelial cell-conditioned dendritic cells released interleukins 10 and 6 but not interleukin 12, and they promoted the polarization of T cells toward a 'classical' noninflammatory T helper type 2 response, even after exposure to a T helper type 1-inducing pathogen.

Helper-dependent adenoviral vector-mediated delivery of woodchuck-specific genes for alpha interferon (IFN-alpha) and IFN-gamma: IFN-alpha but not IFN-gamma reduces woodchuck hepatitis virus replication in chronic infection in vivo.

Alpha interferon (IFN-alpha) and IFN-gamma are able to suppress hepadnavirus replication. The intrahepatic expression of high levels of IFN may enhance the antiviral activity. We investigated the effects of woodchuck-specific IFN-alpha (wIFN-alpha) and IFN-gamma(wIFN-gamma) on woodchuck hepatitis virus (WHV) replication in vivo by helper-dependent adenoviral (HD-Ad) vector-mediated gene transfer.

Expression of a new woodchuck IFN-alpha gene by a helper-dependent adenoviral vector in woodchuck hepatitis virus-infected primary hepatocytes.

Recombinant interferon-alpha (rIFN-alpha) is currently used in the treatment of viral hepatitis either alone or in combination with small molecules. However, this treatment is not very efficacious, and more effective protocols are needed. To this end, we have explored the woodchuck hepatitis system, validated as an infection model for vaccination and antiviral studies against human hepatitis B virus (HBV) infection.

Tight control of gene expression by a helper-dependent adenovirus vector carrying the rtTA2(s)-M2 tetracycline transactivator and repressor system.

Control of gene expression for gene therapy application requires the design of a sophisticated system embodying multiple properties. The ideal system should present the following features: (1) low or undetectable gene expression in the absence of inducer; (2) strong expression upon induction; and (3) fast kinetics of induction in the presence of inducers and rapid reversal of induction after its withdrawal. To evaluate these parameters, the features of the latest generation tetracycline-sensitive reverse-transactivator (rtTA2(s)-M2) alone or in combination with Tet-repressor (tTS-Kid) were explored in the context of helper-dependent adenovirus vector.

Liver-specific alpha 2 interferon gene expression results in protection from induced hepatitis.

The current therapy for hepatitis B and C is based on systemic administration of recombinant human alpha interferon (r-hIFN-alpha). However, systemic delivery of r-hIFN-alpha is associated with severe side effects, but more importantly, it is effective in only a small percentage of patients. In an effort to maximize IFN-alpha antiviral efficacy, we have explored the therapeutic potential of murine IFN-alpha2 (mIFNalpha2) selectively expressed in the liver.