ABSTRACT
Human and mouse studies indicate distinct roles of selected chemokines for monocyte subset attraction. We therefore analyzed the still unknown sensitivity and response of bovine monocyte subsets toward two monocyte-attracting chemokines (CCL2, CCL5). Only CCL5 induced a significant Ca(2+)influx and migration response in bovine monocytes, with classical and intermediate monocytes being significantly stimulated and attracted compared to nonclassical monocytes. The presence of CCL5 during in vitro macrophage differentiation did not alter their capacity to phagocytize or to generate reactive oxygen species upon stimulation with E. coli. However, macrophages differentiated in the presence of CCL5 displayed an altered phenotype with significantly less expressed CD14 and MHC class II molecules, whereas CD16 was upregulated. Moreover, CCL5-differentiated macrophages displayed a reduced upregulation of CXCL8, ARG1, IL6 and IL10 mRNA. Taken together, CCL5 but not CCL2 mainly attract bovine classical monocytes and promote their differentiation into LPS-hypo-responsive macrophages.
Subject(s)
Chemokine CCL5/pharmacology , Chemotaxis/drug effects , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Monocytes/drug effects , Animals , Arginase/genetics , Arginase/immunology , Calcium/metabolism , Cattle , Cell Differentiation/drug effects , Chemokine CCL2/pharmacology , Escherichia coli/immunology , Female , Gene Expression Regulation , Interleukin-10/genetics , Interleukin-10/immunology , Interleukin-6/genetics , Interleukin-6/immunology , Interleukin-8/genetics , Interleukin-8/immunology , Ion Transport/drug effects , Lipopolysaccharide Receptors/genetics , Lipopolysaccharide Receptors/immunology , Macrophages/immunology , Macrophages/metabolism , Monocytes/immunology , Monocytes/metabolism , Phagocytosis/drug effects , Primary Cell Culture , Reactive Oxygen Species/metabolism , Receptors, IgG/genetics , Receptors, IgG/immunologyABSTRACT
The functional phenotype of resident macrophages significantly determines the character of an inflammatory response. In this study we identified two phenotypes of tissue macrophages in bovine teat tissue based on expression of Calprotectin and CD163. To investigate a possible link between the dichotomy in phenotype and functional properties of cells in association with different host mediators we set up an in vitro model with bovine monocyte-derived macrophages (MdM). In vitro differentiated MdM invariably and uniformly expressed both antigens. Classically activated MdM (IFN-γ priming and LPS stimulation) showed a decreased CD163 expression while alternative activation (IL-4/IL-13 priming) did not change expression of CD163 and Calprotectin. Differently activated MdM showed a clearly distinct expression of genes related to classical (IL-12, inducible NO synthase) or alternative activation (IL-10, arginase I). The presence of the inflammatory host mediator prostaglandin E(2) (PGE(2)) neither influenced expression of Calprotectin and CD163 nor gene expression profiles in MdM generated in the presence of PGE(2) (PGE(2)-MdM). Supernatants of PGE(2-)MdM, however, significantly dampened the migration of neutrophilic granulocytes. The results of this study highlight the discrepancy between in vivo and in vitro obtained macrophages and point to the necessity to analyze the functional capacities of bovine tissue macrophages in situ.
