| description |
Porcine dendritic cells (DC) are relatively well characterized but a clear-cut identification of all DC subsets combined with full transcriptional profiling was lacking, preventing an unbiased insight into the functional specializations of DC subsets. Using a large panel of antibodies in multicolor flow cytometry, cell sorting and RNA sequencing we identified and characterized the porcine equivalent of conventional DC (cDC) 1 and cDC2 as well as plasmacytoid DC (pDC) in the peripheral blood of pigs. We demonstrate that cDC1 are CD135+CD14-CD172alowCADM1+wCD11R1+ cells, cDC2 CD135+CD14-CD172a+CADM1+CD115+wCD11R1+CD1+ and pDC CD4+CD135+CD172a+CD123+CD303+ cells. As described in other species only cDC1 express BATF3 and XCR1, cDC2 FCER1A and FCGR2B, and only pDC express TCF4 and NRP1. Nevertheless, despite these cross-species conserved subset-specific transcripts, porcine pDC differed from the species described so far in many expressed genes and transcriptomic profiling clustered pDC more distantly from cDCs than monocytes. The response of porcine DC subsets to TLR ligands revealed that pDCs are by far the most important source of TNF-α, IL-12p40, and of course IFN-α, while cDCs are most efficient in MHC and costimulatory molecules expression. Nevertheless, upregulation of CD40 and CD86 in cDC was critically influenced or even dependent on the presence of pDC in particular for TLR 7 and 9 ligands. Our data demonstrate that extrapolation of data on DC biology from one species to another has to be done with care, and it shows how functional details have differentially evolved in different species. |