Exposure of CD34+ precursors to cytostatic anthraquinone-derivatives induces rapid dendritic cell differentiation: implications for cancer immunotherapy.

Appropriate activation of dendritic cells (DC) is essential for successful active vaccination and induction of cell-mediated immunity. The scarcity of precursor cells, as well as long culture methods, have hampered wide-scale application of DC vaccines derived from CD34(+) precursors, despite their suggested superior efficacy over the more commonly applied monocyte-derived DC (MoDC). Here, employing the CD34(+)/CD14(+) AML-derived human DC progenitor cell line MUTZ3, we show that cytostatic anthraquinone-derivatives (i.

Delivery route, MyD88 signaling and cross-priming events determine the anti-tumor efficacy of an adenovirus based melanoma vaccine.

Adenovirus (Ad)-based vaccines are considered for cancer immunotherapy, yet, detailed knowledge on their mechanism of action and optimal delivery route for anti-tumor efficacy is lacking. Here, we compared the anti-tumor efficacy of an Ad-based melanoma vaccine after intradermal, intravenous, intranasal or intraperitoneal delivery in the B16F10 melanoma model. The intradermal route induced superior systemic anti-melanoma immunity which was MyD88 signaling-dependent.

Selective transduction of dendritic cells in human lymph nodes and superior induction of high-avidity melanoma-reactive cytotoxic T cells by a CD40-targeted adenovirus.

Targeted delivery of tumor antigen genes to dendritic cells (DCs) using adenoviral (Ad) vectors holds great potential for cancer immunotherapy. We previously showed that CD40 targeting of Ad vectors enhanced specific transduction of DC in human skin, while simultaneously ensuring their stable maturation and superior allogeneic T-cell stimulatory capacity. In this study, we evaluated whether CD40-targeted Ad encoding the full-length melanoma antigen recognized by T cells-1 (CD40-Ad-MART-1) could be used to efficiently and selectively transduce conventional and plasmacytoid DC to prime melanoma-specific CD8(+) T-effector cells in human melanoma-draining sentinel lymph nodes (SLNs).

Unimpaired immune functions in the absence of Mrp4 (Abcc4).

Dendritic cell (DC) migration to draining lymph nodes is important for the initiation of an effective immune response. Recently we reported that the human ATP-binding cassette (ABC) transporter multidrug resistance protein 4 (MRP4 and ABCC4) is required for the migration of human DC. Since the ABC transporter MRP1 (ABCC1) was previously shown to play a role in both human and mouse DC migration, we here studied whether Mrp4 is similarly required for DC migration in mice and whether the absence of Mrp4 interferes with the generation of an immune response.

Local administration of PF-3512676 CpG-B instigates tumor-specific CD8+ T-cell reactivity in melanoma patients.

Purpose: Impaired immune effector functions in the melanoma sentinel lymph node (SLN) may allow for early metastatic events. Local administration of PF-3512676 (formerly known as CpG 7909) has shown immunostimulatory effects of both dendritic cell and T-cell subsets in the melanoma SLN. Here, we set out to ascertain whether these PF-3512676-induced immunostimulatory effects translate into higher frequencies of melanoma-specific CD8(+) T cells.

Intradermal CpG-B activates both plasmacytoid and myeloid dendritic cells in the sentinel lymph node of melanoma patients.

Purpose: A decrease in the frequency and activation state of dendritic cells in the sentinel lymph node (SLN) has been observed in early stages of melanoma development. This may hinder the generation of effective antitumor T-cell responses and increase the likelihood of metastatic spread. Immunopotentiation of the melanoma SLN may therefore be a valuable adjuvant treatment option.

Tumor-specific CD8+ T cell reactivity in the sentinel lymph node of GM-CSF-treated stage I melanoma patients is associated with high myeloid dendritic cell content.

Purpose: Impaired immune functions in the sentinel lymph node (SLN) may facilitate early metastatic events during melanoma development. Local potentiation of tumor-specific T cell reactivity may be a valuable adjuvant treatment option.

Experimental Design: We examined the effect of locally administered granulocyte/macrophage-colony stimulating factor (GM-CSF) on the frequency of tumor-specific CD8+ T cells in the SLN and blood of patients with stage I melanoma.

Matched skin and sentinel lymph node samples of melanoma patients reveal exclusive migration of mature dendritic cells.

Mature and immature myeloid dendritic cells (DCs) are thought to differentially modulate T-cell responses in secondary lymphoid tissues. Although mature DCs are believed to induce T-cell activation under proinflammatory conditions, immature DCs are believed to maintain a state of T-cell tolerance under steady state conditions. However, little is known about the actual activation state of human DCs under these different conditions.

The CXCR3 targeting chemokine CXCL11 has potent antitumor activity in vivo involving attraction of CD8+ T lymphocytes but not inhibition of angiogenesis.

The IFN-gamma-inducible and CXCR3-targeting human CXC chemokines CXCL9 (Mig) and CXCL10 (IP10) have potent antitumor activity through attraction of cytotoxic T lymphocytes and inhibition of angiogenesis. The more recently identified CXCR3-targeting chemokine CXCL11 (I-TAC/IP9) proved to be a more potent chemokine than CXCL9 and CXCL10 in vitro, both in chemotaxis assays with CXCR3+ T lymphocytes and in calcium mobilization experiments. However, its antitumor activity in vivo has not been shown so far.

Local administration of granulocyte/macrophage colony-stimulating factor increases the number and activation state of dendritic cells in the sentinel lymph node of early-stage melanoma.

The initial tumor-draining lymph node, the sentinel lymph node, not only constitutes the first expected site of micrometastasis but also the first point of contact between tumor-associated antigens and the adaptive immune system. A tumor-induced decrease in the frequency and activation state of sentinel lymph node dendritic cells will impair the generation of effective antitumor T-cell responses and increase the likelihood of metastatic spread. Here, we demonstrate that intradermal administration of granulocyte macrophage-colony stimulating factor around the excision site of stage I primary melanoma tumors increases the number and activation state of dendritic cells in the paracortical areas of the sentinel lymph node and enhances their binding to T cells.

Sampling tumor-draining lymph nodes for phenotypic and functional analysis of dendritic cells and T cells.

Immune responses against tumor antigens will initially occur in the first tumor-draining lymph node, the sentinel node (SN). Because of extensive diagnostic procedures, obtaining a piece of SN to isolate viable immune cells for functional analyses is often impossible. For this reason an alternative method to obtain viable cells from a lymph node (LN) was investigated, ie, scraping LNs with a surgical blade, and compared with dissociation of total LNs.