Search

Contains fulltext : 142493.pdf (Publisher’s version ) (Open Access) Dendritic cells (DC) are the professional antigen presenting cells of the immune system. Therefore, several clinical studies have been initiated in which tumor antigen-loaded DC are used as a vaccine to boost an immune response against malignant tumors in patients with cancer. A prerequisite for DC used in these vaccination studies is not only that they are grown under "Good Manufacturing Practice" but equally important that they retain their functional properties. In an extensive study, various conditions were tested to optimize the maturation and yield of DC grown for clinical use. DC grown in XVIVO-15 medium supplemented with 5% HS yielded the best results, morphologically and phenotypically. Mature DC expressed significant amounts of mature DC markers (CD83) and the costimulatory molecules CD80 and CD86. It was shown that mature and immature DC can be frozen and retain their phenotype and function after thawing. These clinical grade DC secreted high levels of the chemokines dendritic cell chemokine 1 (DC-CK1), interleukin-8 (IL-8), macrophage-derived chemokine (MDC), and thymus and activation-regulated chemokine (TARC). This implicates that these DC can attract naive T and B cells as well as natural killer cells and memory T cells. Finally, to test their migratory capacity in vivo, (111)In-labeled DC were injected into tumor-free lymph nodes of patients with melanoma. Autoradiographic analysis of the dissected lymph nodes indicated that these DC could migrate into the T cell area of adjacent lymph nodes. In conclusion, a culture procedure was established to generate large numbers of monocyte-derived immature and mature DC that retain their morphologic, phenotypic, and functional characteristics in vitro and can be visualized in situ.

Item does not contain fulltext Dendritic cells (DC) are unique in their ability to present antigen to naive T cells, and therefore play a central role in the initiation of immune responses. Characterization of DC-specific genes may help to unravel the mechanism underlying their potent antigen presenting capacity. Here we describe the identification of a novel transcript, isolated by random sequencing of a cDNA library prepared from monocyte-derived DC, which we termed DC-specific transmembrane protein (DC-STAMP). DC-STAMP is specifically expressed by DC, and not in a panel of other leukocytes or non-hematopoietic cells. Interestingly, DC-STAMP was also detected in activated but not resting blood DC. The DC-STAMP transcript encodes a 470-amino acid protein containing seven putative transmembrane domains. Expression of a DC-STAMP-GFP fusion protein in 293 cells indicates that DC-STAMP is expressed at the cell surface, and has an intracellular C terminus. Surprisingly, no sequence homology was found with any other protein or multimembrane-spanning receptor. Therefore, we propose that DC-STAMP is a novel DC-specific multimembrane-spanning protein, representing a new group of transmembrane proteins.

Item does not contain fulltext

Contains fulltext : 146794.pdf (Publisher’s version ) (Open Access) 151 p.