Antigens encoded by MAGE genes are of particular interest for cancer immunotherapy because they are tumor specific and shared by tumors of different histological types. Several clinical trials are in progress with MAGE peptides, proteins, recombinant poxviruses, and dendritic cells (DC) pulsed with peptides or proteins. The use of gene-modified DC would offer the major advantage of a long-lasting expression of the transgene and a large array of antigenic peptides that fit into the different HLA molecules of the patient. In this study, we tested the ability of gen...

T helper (Th) cells are central regulators of adaptive immune responses. However, the detection of the small number of Th cells specific for a particular antigen or pathogen is still a major challenge. CD154 was recently introduced as a marker for antigen-specific Th cells. To date, this technology was not applicable for mice - arguably the most important immunological model system. CD154 is difficult to detect due to its rapid removal from the cell surface upon binding to CD40 during antigen-specific activation by APC. We present an efficient strategy to block th...

With the recent advances in human-hemato-lymphoid-system mice, this commentary discusses the utility of these mice and further improvements required to generate an accessible system that allows predictive in vivo human hematology and immunology research.

The molecular mechanisms that regulate expression of the immunosuppressive cytokine IL-10 remain poorly understood. In this study, by measuring sensitivity to DNase I digestion, we show that production of IL-10 by primary mouse bone marrow-derived macrophages stimulated through pattern recognition receptors was associated with chromatin remodeling of the IL-10 locus. We also demonstrate that the IL-10 locus is remodeled in primary Th2 cells and IL-10-producing regulatory T cells that have been differentiated in vitro. Strikingly, a novel DNase I-hypersensitive si...

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...

Dendritic cell (DC) populations play unique and essential roles in the detection of pathogens, but information on how different DC types work together is limited. In this study, 2 major DC populations of human blood, myeloid (mDCs) and plasmacytoid (pDCs), were cultured alone or together in the presence of pathogens or their products. We show that pDCs do not respond to whole bacteria when cultured alone, but mature in the presence of mDCs. Using purified stimuli, we dissect this cross-talk and demonstrate that mDCs and pDCs activate each other in response to spe...

AIMS/HYPOTHESIS: In the human pancreas, a close topographic relationship exists between duct cells and beta cells. This explains the high proportion of duct cells in isolated human islet preparations. We investigated whether human duct cells are a source of TNFalpha-mediated interactions with beta cells and immune cells. This cytokine has been implicated in the development of autoimmune diabetes in mice. METHODS: Human duct cells were isolated from donor pancreases and examined for their ability to produce TNFalpha following a stress-signalling pathway. Duct-cell...

The transcription factor Foxo1 regulates the homeostasis of naive peripheral T cells by 'translating' nutrient-availability signals into the expression of lymphoid tissue–homing molecules and the receptor for interleukin 7.

Dendritic cells (DCs) play a crucial role in bridging innate and acquired immune responses to pathogens. In human immunodeficiency virus type 1 (HIV-1) infection, immature DCs (iDCs) are also main targets for HIV-1 at the mucosal level. In this study, we evaluated the effects of HIV-1-DC interactions on the maturation and functional activity of these cells. Exposure of human monocyte-derived iDCs to either aldrithiol-2-inactivated HIV-1 or gp120 led to an upmodulation of activation markers indicative of functional maturation. Despite their phenotype, these cells ...

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. ...

To study DNA vaccination directed against human HER-2 in the HHD mouse Tg strain, we created a novel HER-2-expressing syngeneic tumor transplantation model. We found that a DNA vaccine encoding the full length HER-2 DNA protected HHD mice from HER-2(+) tumor challenge by a CTL independent mechanism. A more efficient approach to induce HLA-A2 restricted CTLs, through immunization with a multi-epitope DNA vaccine expressing the HLA-A2 restricted HER-2 369-377, 435-443 and 689-697 epitopes, resulted in high numbers of peptide specific T cells but failed to induce tu...

Mature dendritic cells (DCs) are the most potent antigen-presenting cells within the human immune system. However, Herpes simplex virus type 1 (HSV-1) is able to interfere with DC biology and to establish latency in infected individuals. In this study, we provide new insights into the mechanism by which HSV-1 disarms DCs by the manipulation of CD83, a functionally important molecule for DC activation. Fluorescence-activated cell sorter (FACS) analyses revealed a rapid downmodulation of CD83 surface expression within 6 to 8 h after HSV-1 infection, in a manner stri...

Melanoma metastases are characterized by pronounced neo-angiogenesis and spontaneous bleeding frequently occurring within central nervous system metastases. Clinically apparent spontaneous hemorrhage within subcutaneous melanoma metastases, however, is a rare event that coincides with progression of such metastases. We report, to our knowledge the first observation, on regression of subcutaneous metastases with hemorrhage of the overlying skin in three patients with stage IV melanoma who participated in clinical trials on therapeutic vaccination. In two patients,...

To optimize vaccination strategies, it is important to use protocols that can 'jump-start' immune responses by harnessing cells of the innate immune system to assist the expansion of antigen-specific B and T cells. In this Review, we discuss the evidence indicating that invariant natural killer T (iNKT) cells can positively modulate dendritic cells and B cells, and that their pharmacological activation in the presence of antigenic proteins can enhance antigen-specific B- and T-cell responses. In addition, we describe structural and kinetic analyses that assist in...

Dendritic cells (DCs) play a key role in the orchestration of the immune system by virtue of their capacity to control both immunity and tolerance induction. The functions of DCs depend on the subset as well as their location and activation state. A number of in vitro protocols, developed to recapitulate DC generation from hematopoietic precursors, have suggested the importance of microenvironment and cytokine milieu in driving the generation of DCs endowed with peculiar phenotypic and functional features. Recently, some important concepts on the development of D...

Background The generation of Ag-loaded DC under good manufacturing practice (GMP) conditions is logistically challenging and further compounded when the starting precursors need to be purified from B-CLL patients who have overwhelming numbers of circulating B-CLL cells and decreased numbers of monocytes. Methods We have previously demonstrated that DC with endocytosed B-CLL apoptotic bodies are powerful stimulators of anti-leukemic T cells. In this study we compared counterflow elutriation and immunomagnetic separation for enriching monocyte precursors, and eva...

IL-10 is a major regulator in inflammatory responses. Although various transcription factors were defined to enhance IL-10, the molecular mechanism for the initiation of Il-10 transcription, remains unknown. mRNA profiling of six distinct primary CD4+ T cell populations showed differential expression of the transcription factor GATA-3 correlated with levels of IL-10 expression. We showed that ectopic expression of GATA-3 in naive primary CD4+ T cells enhanced expression of IL-10 by these cells and uncovered a possible mechanism for this effect. We found that GATA...