Gene Family Clustering Identifies Functionally Associated Subsets of Human In Vivo Blood and Tonsillar Dendritic Cells

Abstract

Human dendritic cells (DCs) are a distinct but heterogeneous lineage of APCs operating as the link between innate and adaptive immune responses, with the function to either maintain tolerance or trigger immunity. The DC lineage consists of several subpopulations with unique phenotypes; however, their functional characteristics and transcriptional similarities remain largely unknown. To further characterize the phenotypes and transcriptomes of the subsets, we purified myeloid CD16+, blood DC Ag 1+ (BDCA1+), and BDCA3+ DC populations, as well as plasmacytoid CD123+ DCs, from tonsillar tissue and peripheral blood. Transcriptional profiling and hierarchical clustering visualized that BDCA1+ DCs clustered with BDCA3+ DCs, whereas CD16+ DCs and CD123+ DCs clustered as distinct populations in blood. Differential expression levels of chemokines, ILs, and pattern recognition receptors were demonstrated, which emphasize innate DC subset specialization. Even though highly BDCA1+ and BDCA3+ DC-specific gene expression was identified in blood, the BDCA1+ DCs and BDCA3+ DCs from tonsils displayed similar transcriptional activity, most likely due to the pathogenic or inflammatory maturational signals present in tonsillar tissues. Of note, plasmacytoid DCs displayed less plasticity in their transcriptional activity compared with myeloid DCs. The data demonstrated a functionally distinct association of each of the seven subsets based on their signatures, involving regulatory genes in adaptive and innate immunity.

Differential Pattern Recognition Receptor Expression but Stereotyped Responsiveness in Rat Spleen Dendritic Cell Subsets

“…However, it is difficult to draw conclusions before TLR9 expression in lymphoid organ-derived DC has been assessed in humans. In fact, a recent study has shown strong TLR9 gene expression in BDCA3 ϩ tonsillar DC (34). Like human CD11c ϩ DC, OX62 ϩ rat DC expressed a much broader TLR repertoire than pDC.…”

Dendritic Cells

“…Human pDCs lack expression of CD11c and are discriminated by the expression of BDCA2, BDCA4 and/or CD123. CD16 + MHC class II + cells cluster as a distinct population in the blood (Lindstedt et al 2005 ) and have previously been associated with DC origins by some. However, CD16 + cells were recently assigned to the monocyte lineage (Robbins et al 2008 ;Ziegler-Heitbrock et al 2010 ), confi rmed by transcript profi ling comparing CD16 + cells with BDCA1 + DCs (Frankenberger et al 2012 ).…”

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

“…24 T2 cells were pulsed with 10 mg/mL WT1 126-134 , Kallikrein 4 11¡19 (KLK4; FLGYLILGV)) or MART1 [26][27][28][29][30][31][32][33][34][35] peptide in X-Vivo 15 for 2 h and stained with 2.5 mM calcein-AM. Antigen specific cytotoxicity was measured after 3 h incubation at 37 C using a 50:1 effector:target ratio on an Enspire plate reader (Perkin Elmer) with an excitation at 485 nm and fluorescent emission at 520 nm.…”

“…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).…”

“…However, the properties of Mo-DC were shown to differ substantially from those of primary "in vivo" derived BDC, [23][24][25] and it is now well accepted that there are significant transcriptional and functional differences between Mo-DC and BDC. 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.…”