Fluorescent activated cell sorting: An effective approach to study dendritic cell subsets in human atherosclerotic plaques

Different immune cell types are present within atherosclerotic plagues. Dendritic cells (DC) are of special interest, since they are considered as the 'center of the immuniverse'. Identifying inflammatory DC subtypes within plagues is important for a better understanding of the lesion pathogenesis and pinpoints their contribution to the atherosclerotic process. We have developed a flow cytometry-based method to characterize and isolate different DC subsets (i.e. CD11b(+), Clec9A(+) and CD16(+) conventional (c)DC and CD123(+) plasmacytoid (p)DC) in human atherosclerotic plagues. We revealed a predominance of pro-inflammatory CD11b(+) DC in advanced human lesions, whereas atheroprotective Clec9A(+) DC were almost absent. CD123(+) pDC and CD16(+) DC were also detectable in plagues. Remarkably, plagues from distinct anatomical locations exhibited different cellular compositions: femoral plagues contained less CD11b(+) and Clec9A(+) DC than carotid plagues. Twice as many monocytes/macrophages were observed compared to DC. Moreover, relative amounts of T cells/B cells/NI(cells were 6 times as high as DC numbers. For the first time, fluorescent activated cell sorting analysis of DC subsets in human plaques indicated a predominance of CD11b(+) cDC, in comparison with other DC subsets. Isolation of the different subsets will facilitate detailed functional analysis and may have significant implications for tailoring appropriate therapy. (C) 2014 Elsevier B.V. All rights reserved.