We report here that HLA-DRbeta4*01 restricted MAGE-A3(161-175 )specific CD4(+) T cells from a healthy donor recognize a naturally processed epitope formed through the exogenous but not the endogenous pathway. However, the intensity of recognition of the native epitope by MAGE-A3(161-175 )specific CD4(+) T cells strongly depends on the antigen presenting cells and the amount of protein available for processing. EBV-transformed lymphoblastoid cells (LCLs) and melanoma cells engineered to express MAGE-A3 in the endosomal/lysosomal compartment were strongly recognized...

hMena (ENAH), an actin regulatory protein involved in the control of cell motility and adhesion, is modulated during human breast carcinogenesis. In fact, whereas undetectable in normal mammary epithelium, hMena becomes overexpressed in high-risk benign lesions and primary and metastatic tumors. In vivo, hMena overexpression correlates with the HER-2(+)/ER(-)/Ki67(+) unfavorable prognostic phenotype. In vitro, neuregulin-1 up-regulates whereas Herceptin treatment down-modulates hMena expression, suggesting that it may couple tyrosine kinase receptor signaling to t...

In response to inflammatory stimulation, dendritic cells (DCs) have a remarkable pattern of differentiation (maturation) that exhibits specific mechanisms to control antigen processing and presentation. Here, we show that in response to lipopolysaccharides, protein synthesis is rapidly enhanced in DCs. This enhancement occurs via a PI3K-dependent signaling pathway and is key for DC activation. In addition, we show that later on, in a manner similar to viral or apoptotic stress, DC activation leads to the phosphorylation and proteolysis of important translation ini...

Human papillomavirus (HPV)-induced malignancies are frequently infiltrated by lymphocytes. To comprehend the contribution of HPV-specific T cells in this anti-tumor response we developed a method that allowed the analysis of the presence and specificity of cervix-infiltrating and draining lymph node resident T cells in a group of 74 patients with cervical malignancies, 54 of which were induced by HPV16 or HPV18. We detected the presence of HPV16 or HPV18-specific T cells in at least 23 of the 54 HPV-16 or -18 positive patients, and not in the 20 controls. Detailed...

Cervical neoplastic lesions are associated with infection by high-risk human papilloma viruses (HPVs). HPV-16 and HPV-18 are the most common genotypes. It has been proposed that development of HPV-16-positive cervical lesions is associated with impaired CD4(+) T cell immunity against early Ags. The aim of the study was to evaluate whether this impairment also applies to HPV-18. We investigated the presence and the quality of anti-HPV-18 E6 CD4(+) T cell responses in the blood of 37 consecutive patients with high-grade cervical lesions, 25 normal donors, and 20 cor...

In a prospective study, we have examined the tumor-specific immune response in a group of 59 patients with human papillomavirus (HPV) 16-positive (HPV16(+))-induced or HPV18(+)-induced cervical cancer. Local antitumor immunity was analyzed by the enumeration of tumor-infiltrating dendritic cells and CD4+, CD8+, and regulatory T cells as well as by calculation of the ratio of CD8+/CD4+ T cells and CD8+/regulatory T cells. Systemic tumor-specific immunity was assessed by determination of the HPV E6- and/or E7-specific T-cell response in the blood of these patients. ...

A systematic comparison of the immunostimulatory capacity of TLR 2, 3, 4, 5, 7 and 9 agonists and an agonistic CD40-specific antibody was performed in a single long peptide vaccination model. All adjuvants activated DC in vitro but not all induced a strong functional T-cell response in vivo. Optimal clonal CD8(+) T-cell expansion depended on the capacity of agonists to mature pro-inflammatory DC and the duration of their in vivo stimulatory effect. Strong agonists promoted the induction of both antigen-specific IFNgamma-producing CD4(+) T-helper cells and high num...

The effectiveness of T-cell-mediated immunotherapy of cancer depends on both an optimal immunostimulatory context of the therapy and the proper selection with respect to quality and quantity of the targeted tumor-associated antigens (TAA), and, more precisely, the T-cell epitopes contained in these tumor proteins. Our progressing insight in human leukocyte antigen (HLA) class I and class II antigen processing and presentation mechanisms has improved the prediction by reverse immunology of novel cytotoxic T lymphocyte and T-helper cell epitopes within known antigen...

Synthetic peptide vaccines aiming at the induction of a protective CD8(+) T-cell response against infectious or malignant diseases are widely used in the clinic but, despite their success in animal models, they do not yet live up to their promise in humans. This review assesses the development of synthetic peptide vaccines, weighs it against the immunological concepts that have emerged, and identifies the key issues that play a role in the failure or success of a synthetic peptide vaccine. The current state-of-the-art peptide vaccine is a complete synthetic inflam...

Because of their important role in the maintenance of self-tolerance, CD4(+) regulatory T cells prevent autoimmune diseases but also curtail the efficacy of T cell immune responses against cancers. We now show that this suppressive action of CD4(+) regulatory T cells is not limited to cancers displaying tumor-associated self antigens, such as melanomas, but also extends to human papillomavirus (HPV)-positive cervical cancers that express foreign tumor antigens. HPV-specific CD4(+) T cells isolated from lymph node biopsies of cervical cancer patients were found to ...

Since their discovery, there has been significant progress in the understanding of dendritic cell (DC) biology. Their capacity for priming an immune response against pathogens and cancers has been exploited clinically. However, the objective responses obtained to date using DC cancer vaccines have been modest. Suboptimal DC preparations, limited tumor target antigens, and the essential need to initiate trials in immunocompromised patients with advanced disease, have all contributed to limited outcomes. The use of fully activated DCs, loaded with multiple, immunoge...

Therapeutic vaccination trials, in which patients with cancer were vaccinated with minimal CTL peptide in oil-in-water formulations, have met with limited success. Many of these studies were based on the promising data of mice studies, showing that vaccination with a short synthetic peptide in IFA results in protective CD8(+) T cell immunity. By use of the highly immunogenic OVA CTL peptide in IFA as a model peptide-based vaccine, we investigated why minimal CTL peptide vaccines in IFA performed so inadequately to allow full optimization of peptide vaccination. In...

Antigen (Ag) capture and presentation onto major histocompatibility complex (MHC) class II molecules by B lymphocytes is mediated by their surface Ag receptor (B cell receptor [BCR]). Therefore, the transport of vesicles that carry MHC class II and BCR-Ag complexes must be coordinated for them to converge for processing. In this study, we identify the actin-associated motor protein myosin II as being essential for this process. Myosin II is activated upon BCR engagement and associates with MHC class II-invariant chain complexes. Myosin II inhibition or depletion c...

Previously, we found that human dendritic cells (hDCs) pulsed with a melanoma cell lysate (MCL) and stimulated with TNF-alpha (MCL/TNF) acquire a mature phenotype in vitro and are able to trigger tumor-specific immune responses when they are used in melanoma immunotherapy in patients. In this study, we describe that MCL/TNF induces gap junction (GJ)-mediated intercellular communications and promotes melanoma Ag transfer between ex vivo produced hDCs from melanoma patients. hDCs also exhibit increased expression of the GJ-related protein connexin 43, which contribu...

MOTIVATION: Eu.Gene Analyzer is an easy-to-use, stand-alone application that allows rapid and powerful microarray data analysis in the context of biological pathways. Its intuitive graphical user interface makes it an easy and flexible tool, even for the first-time user. Eu.Gene supports a variety of array platforms, organisms and pathway ontologies, transparently deals with multiple nomenclature systems and seamlessly integrates data from different sources. Two different statistical methods, the Fisher Exact Test and the Gene Set Enrichment Analysis (GSEA), are i...

Antigen binding to the B-cell receptor (BCR) induces multiple signaling cascades that ultimately lead to B lymphocyte activation. In addition, the BCR regulates the key trafficking events that allow the antigen to reach endocytic compartments devoted to antigen processing, i.e., that are enriched for major histocompatibility factor class II (MHC II) and accessory molecules such as H2-DM. Here, we analyze the role in antigen processing and presentation of the tyrosine kinase Syk, which is activated upon BCR engagement. We show that convergence of MHC II- and H2-DM-...

Myeloid dendritic cells (DC) and macrophages evolve from a common precursor. However, factors controlling monocyte differentiation toward DC or macrophages are poorly defined. We report that the surface density of the GM-CSF receptor (GM-CSFR) alpha subunit in human peripheral blood monocytes varies among donors. Although no correlation was found between the extent of GM-CSFR and monocyte differentiation into DC driven by GM-CSF and IL-4, GM-CSFR expression strongly influenced the generation of CD1a(+) dendritic-like cells in the absence of IL-4. CD1a(+) cells gen...

Interferon (IFN)-gamma, a cytokine critical for resistance to infection and tumors, is produced by CD4(+) helper T lymphocytes after stimulation by cultured dendritic cells (DCs) that secrete a cofactor, interleukin (IL)-12. We have identified a major IL-12-independent pathway whereby DCs induce IFN-gamma-secreting T helper (Th)1 CD4(+) T cells in vivo. This pathway requires the membrane-associated tumor necrosis family member CD70 and was identified by targeting the LACK antigen from Leishmania major within an antibody to CD205 (DEC-205), an uptake receptor on a ...