Limited Amounts of Dendritic Cells Migrate into the T-Cell Area of Lymph Nodes but Have High Immune Activating Potential in Melanoma Patients

Abstract

Purpose: The success of immunotherapy with dendritic cells (DC) to treat cancer is dependent on effective migration to the lymph nodes and subsequent activation of antigen-specificTcells. In this study, we investigated the fate of DC after intradermal (i.d.) or intranodal (i.n.) administration and the consequences for the immune activating potential of DC vaccines in melanoma patients. Experimental Design: DC were i.d. or i.n. administered to 25 patients with metastatic melanoma scheduled for regional lymph node resection. To track DC in vivo with scintigraphic imaging and in lymph nodes by immunohistochemistry, cells were labeled with both [ 111 In]-indium and superparamagnetic iron oxide. Results: After i.d. injection, maximally 4% of the DC reached the draining lymph nodes. When correctly delivered, all DC were delivered to one or more lymph nodes after i.n. injection. Independent of the route of administration, large numbers of DC remained at the injection site, lost viability, and were cleared by infiltrating CD163+ macrophages within 48 hours. Interestingly, 87 F 10% of the surviving DC preferentially migrated into the T-cell areas, where they induced antigen-specificT-cell responses. Even though more DC reached theT-cell areas, i.n. injection of DC induced similar antigen-specific immune responses as i.d. injection. Immune responses were already induced with <5 Â 10 5 DC migrating into theT-cell areas. Conclusions: Monocyte-derived DC have high immune activating potential irrespective of the route of vaccination. Limited numbers of DC in the draining lymph nodes are sufficient to induce antigen-specific immunologic responses.

CMRF-56+blood dendritic cells loaded with mRNA induce effective antigen-specific cytotoxic T-lymphocyte responses

“…These are both transcriptionally and functionally different to BDC and fail to migrate after injection to draining LNs, despite various manipulations to correct this deficit. 31,32 Given the potential of therapeutic DC vaccination for treating hematological and other malignancies, there is merit in investigating the postulated advantages of using primary BDC as an alternative to Mo-DC. 1 Initial clinical studies have shown that immune selected BDC preparations are safe and able to induce clinical responses in patients.…”

“…Limited numbers of Mo-DC drain to the LN 24 h after injection and the vast majority remain at the site of injection. 31,32 Thus, we were particularly interested in how CMRF-56 C BDC migrated and whether their transfection with IVT-mRNA impacted this. The unique potential of BDC was once again emphasized by their specific migration to the LN homing chemokine CCL21, whereas there was little response by other APC, notably B cells and monocytes.…”

“…The relatively poor migration of Mo-DC from injection sites to draining LNs reported in clinical studies 31,32 prompted us to test the migration capacity of CMRF-56 C APC including BDC, B cells and monocytes. In vitro transwell chemotaxis assays established that transfection did not impair BDC migration to CCL21 and perhaps slightly increased their migratory capacity (Figs.…”

“…24 [25][26][27][28][29][30][31][32][33][34][35] (ELAGIGILTV) peptides (Mimotopes) or expanded using peptide loaded, mitomycin C (Sigma-Aldrich, M-4287-2MG) treated autologous PBMC as described. 24 WT1-specific T cells generated following T-cell expansion were monitored using HLA-A Ã 0201:WT1 126-134 dextramers (Immudex).…”

“…12,14,17,22,[25][26][27][28][29][30] A major concern regarding the use of Mo-DC for therapeutic vaccination has been their well-documented failure to migrate from sites of injection to draining lymph nodes (LN). 31,32 This suggests that the efficacy seen in some studies may relate to an adjuvant or antigen-transfer effect to host DC present at the site of injection. Replacing Mo-DC manufactured in vitro with primary BDC has two potential advantages: (1) BDC are likely to be superior antigen-presenting cells (APC), due to their specialized native antigen-presenting capacity and their potential to migrate more effectively than their in vitro counterparts; 1 (2) it simplifies the preparation, avoiding expensive long-term culture and regulatory processes.…”