Transcriptional patterns associated with BDCA3 expression on BDCA1⁺ myeloid dendritic cells

Myeloid dendritic cells, including BDCA3^hi DCs and BDCA1⁺ DCs (hereafter dubbed DC1 and DC2 for clarity), play a pivotal role in the induction and regulation of immune responses. Interestingly, a fraction of DC2 also express low to intermediate levels of BDCA3. It is unknown whether BDCA3⁺ DC2 also share other traits with DC1 that are absent in BDCA3^- DC2 and/or whether BDCA3 expression renders DC2 functionally distinct from their BDCA3-lacking counterparts. Here, we used expression analysis on a predefined set of immunology-related genes to determine divergence between BDCA3-positive and BDCA3-negative DC2 and their relation to bona fide BDCA3^hi DC1. Results showed that mRNA fingerprints of BDCA3⁺ DC2 and BDCA3^- DC2 are very similar, and clearly distinct from that of DC1. Differences in mRNA expression, however, were observed between BDCA3⁺ DC2 and BDCA3^- DC2 that pointed toward a more activated status of BDCA3⁺ DC2. In line with this, higher steady state maturation marker expression and TLR-induced maturation marker expression and inflammatory cytokine production by BDCA3⁺ DC2 were observed. This dataset provides insight into the relationship between myeloid DC populations and contributes to further understanding of DC immunobiology.