A new and efficient culture method for porcine bone marrow-derived M1- and M2-polarized macrophages

• Published in: Veterinary immunology and immunopathology 2018-06, Vol.200, p.7-15
• Main Authors: Gao, Jiye, Scheenstra, Maaike R., van Dijk, Albert, Veldhuizen, Edwin J.A., Haagsman, Henk P.
• Format: Article
• Language: English
• Subjects: Animals; Antigens, CD - metabolism; Antigens, Differentiation, Myelomonocytic - metabolism; CD163; Cell Polarity; Cells, Cultured; Cytokines - metabolism; Enzyme-Linked Immunosorbent Assay - veterinary; Flow Cytometry - veterinary; Granulocyte-Macrophage Colony-Stimulating Factor - pharmacology; Humans; IL-10; Inflammation - veterinary; Interleukin-10 - metabolism; Macrophage; Macrophage Colony-Stimulating Factor - pharmacology; Macrophages - drug effects; Macrophages - metabolism; Porcine; Receptors, Cell Surface - metabolism; Swine
• ISSN: 0165-2427; 1873-2534
• DOI: 10.1016/j.vetimm.2018.04.002

•Pig M1 and M2 macrophages are most efficiently cultured from bone marrow cells.•Porcine M1 and M2 macrophages resemble human M1 and M2 macrophages.•CD163 and IL-10 can be used to differentiate between M1 and M2 macrophages. Macrophages play an important role in the innate immune system as part of the mononuclear phagocyte system (MPS). They have a pro-inflammatory signature (M1-polarized macrophages) or anti-inflammatory signature (M2-polarized macrophages) based on expression of surface receptors and secretion of cytokines. However, very little is known about the culture of macrophages from pigs and more specific about the M1 and M2 polarization in vitro. Porcine monocytes or mononuclear bone marrow cells were used to culture M1- and M2-polarized macrophages in the presence of GM-CSF and M-CSF, respectively. Surface receptor expression was measured with flow cytometry and ELISA was used to quantify cytokine secretion in response to LPS and PAM3CSK4 stimulation. Human monocyte-derived macrophages were used as control. Porcine M1- and M2-polarized macrophages were cultured best using porcine GM-CSF and murine M-CSF, respectively. Cultures from bone marrow cells resulted in a higher yield M1- and M2-polarized macrophages which were better comparable to human monocyte-derived macrophages than cultures from porcine monocytes. Porcine M1-polarized macrophages displayed the characteristic fried egg shape morphology, lower CD163 expression and low IL-10 production. Porcine M2-polarized macrophages contained the spindle-like morphology, higher CD163 expression and high IL-10 production. Porcine M1- and M2-polarized macrophages can be most efficiently cultured from mononuclear bone marrow cells using porcine GM-CSF and murine M-CSF. The new culture method facilitates more refined studies of porcine macrophages in vitro, important for both porcine and human health since pigs are increasingly used as model for translational research.