Autologous dendritic cells loaded with antigens from self-renewing autologous tumor cells as patient-specific therapeutic cancer vaccines

A promising personal immunotherapy is autologous dendritic cells (DC) loaded ex vivo with autologous tumor antigens (ATA) derived from self-renewing autologous cancer cells. DC-ATA are suspended in granulocyte-macrophage colony stimulating factor at the time of each subcutaneous injection. Previously, irradiated autologous tumor cell vaccines have produced encouraging results in 150 cancer patients, but the DC-ATA vaccine demonstrated superiority in single-arm and randomized trials in metastatic melanoma. DC-ATA have been injected into more than 200 patients with melanoma, glioblastoma, and ovarian, hepatocellular, and renal cell cancers. Key observations include: [1] greater than 95% success rates for tumor cell cultures and monocyte collection for dendritic cell production; [2] injections are well-tolerated; [3] the immune response is rapid and includes primarily TH1/TH17 cellular responses; [4] efficacy has been suggested by delayed but durable complete tumor regressions in patients with measurable disease, by progression-free survival in glioblastoma, and by overall survival in melanoma.

Differential expression of inflammatory chemokines by Th1- and Th2-cell promoting dendritic cells: a role for different mature dendritic cell populations in attracting appropriate effector cells to peripheral sites of inflammation

Protective immunity to pathogens depends on efficient immune responses adapted to the type of pathogen and the infected tissue. Dendritic cells (DC) play a pivotal role in directing the effector T cell response to either a protective T helper type 1 (Th1) or type 2 (Th2) phenotype. Human monocyte-derived DC can be differentiated into Th1-, Th2- or Th1/Th2-promoting DC in vitro upon activation with microbial compounds or cytokines. Host defence is highly dependent on mobile leucocytes and cell trafficking is largely mediated by the interactions of chemokines with their specific receptors expressed on the surface of leucocytes. The production of chemokines by mature effector DC remains elusive. Here we assess the differential production of both inflammatory and homeostatic chemokines by monocyte-derived mature Th1/Th2-, Th1- or Th2-promoting DC and its regulation in response to CD40 ligation, thereby mimicking local engagement with activated T cells. We show that mature Th1- and Th1/Th2-, but not Th2-promoting DC, selectively express elevated levels of the inflammatory chemokines CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta and CCL5/RANTES, as well as the homeostatic chemokine CCL19/MIP-3beta. CCL21/6Ckine is preferentially expressed by Th2-promoting DC. Production of the Th1-attracting chemokines, CXCL9/Mig, CXCL10/IP-10 and CXCL11/I-TAC, is restricted to Th1-promoting DC. In contrast, expression of Th2-associated chemokines does not strictly correlate with the Th2-promoting DC phenotype, except for CCL22/MDC, which is preferentially expressed by Th2-promoting DC. Because inflammatory chemokines and Th1-associated chemokines are constitutively expressed by mature Th1-promoting DC and CCL22/MDC is constitutively expressed by mature Th2-promoting DC, we propose a novel role for mature DC present in inflamed peripheral tissues in orchestrating the immune response by recruiting appropriate leucocyte populations to the site of pathogen entry.

Identification of the genes differentially expressed in human dendritic cell subsets by cDNA subtraction and microarray analysis

Recent studies on dendritic cell (DC)–associated genes have been performed using monocyte-derived DCs (MoDCs) in different maturation stages. In our approach, to uncover the novel DC-associated genes and their expression profiles among the different DC subsets, we constructed a subtracted DC-cDNA library from CD1a+, CD14+, and CD11c− DCs by subtracting the genes shared with T cells, B cells, and monocytes, and we then screened the libraries with the aid of microarray technique. The genes showing remarkable specificity to DCs in the microarray analysis were selected and confirmed by semiquantitative reverse transcriptase–polymerase chain reaction. Our investigations revealed the following: (1) Genes highly expressed in myeloid DCs are those involved in antigen uptake/processing/presentation, cell metamorphosis, or chemotaxis. (2) Most of the genes previously identified in MoDCs, such as TARC, ferritin L-chain, lysosomal acid lipase, α- and β-tubulin, osteopontin (Eta-1), and others, are not markedly expressed in CD11c− DCs regardless of their maturation status. On the other hand, specific transcription factors and MHC class II molecules, such as interferon regulatory factor-4 (IRF4) and HLA-DR, are similarly expressed in both DC subsets. (3) CD14+ DCs retain unique features of tissue DCs, as evidenced by the gene expression profile of “no CCR7 but more CCR1” and “no TARC but abundant MCP1 and Eta-1.” (4) The genes for immunoglobulin (Ig) superfamily Z39Ig, CD20-like precursor, glycoprotein NMB (GPNMB), transforming growth factorβ (TGF-β)–induced protein (TGFBI), myeloid DAP12-associated lectin (MDL-1), and 6 novel genes are newly identified as being associated with the phenotypic expression of the DC subsets. These identifications provide important molecular information for further functional studies of the DC subsets.