Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement
The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.
Identification of Specific Phenotypic Markers for HUMAN Polarized Macrophages
Ambarus1, Carmen A., Krausz1, Sarah, van Eijk1, Marco, Hamann1, Jorg, Tak2, Paul P., Baeten3, D.
The concept of macrophage polarization describes the heterogeneity of activated macrophages under specific microenvironmental conditions. Based on their pro- or anti-inflammatory functions in mice, two major types of macrophages (M1 and M2) have been described. According to this paradigm, we aim to assess type 2 inflammation in spondyloarthritis (SpA) versus type 1 inflammation in rheumatoid arthritis (RA). Here, we investigated the expression of cell surface molecules on in vitro differentiated human macrophages in order to identify reliable markers for characterization of polarized human macrophages in vivo.
Monocytes were isolated from peripheral blood of healthy donors and differentiated in vitro for 4 days in the presence of GM-CSF, IFN-g, LPS, TNF-a, M-CSF, IL-4, or IL-10. Expression of CD14, CD16, CD32, CD64, CD80, CD86, TLR2, TLR4, CD 163, CD200R and CD206 was analyzed by flow cytometry.
M1 macrophages are prototypically induced by IFN-g (M1a) or by TNF-a or bacterial components like LPS (M1b). In our analysis, IFN-g induced selective up-regulation of CD64 and CD80, while LPS strongly up-regulated CD14. M2 cells develop in the presence of IL-4 or IL-13 (M2a), immune complexes (M2b), or IL-10, TGF-b, or glucocorticoids (M2c). IL-4 up-regulated CD200R expression whereas IL-10 strongly up-regulated the expression of CD163 and, to a lesser extent, CD16. In contrast to mouse macrophages, CD206 was not a specific marker for IL-4 polarized macrophages in humans. Additionally, CD86 was not only up-regulated by IFN-g but also by Il-4. TLR2 and TLR4 did not display a specific expression profile. The expression of specific phenotypic markers by polarized cells was similar for monocytes in healthy controls, RA, and SpA. However, the phenotype defined here upon polarization of fresh peripheral blood monocytes only partially holds through when polarizing already matured macrophages. Especially LPS induced up-regulation of different M1 and M2 markers.
Our data indicate that CD64 and CD80 are specific surface markers for in vitro-polarized M1a macrophages and CD14 for the M1b phenotype. CD200R specifically characterizes the M2a and CD163 and CD16 the M2c macrophages. These phenotypic markers now allow to classify polarized human macrophages in inflamed tissue and to assess the function and signalling pathways of specific macrophage subsets.
To cite this abstract, please use the following information:
Ambarus, Carmen A., Krausz, Sarah, van Eijk, Marco, Hamann, Jorg, Tak, Paul P., Baeten, D.; Identification of Specific Phenotypic Markers for HUMAN Polarized Macrophages [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1447