Phenotypic and functional heterogeneity of CD169+ and CD163+ macrophages from porcine lymph nodes and spleen

• Macrophage subtypes in porcine secondary lympoid organs.
• Receptors expressed on macrophages.
• Functional analysis of macrophage subtypes.

Secondary lymphoid organ macrophages are involved in the establishment of innate and acquired immunity. Here, we have isolated and characterized porcine lymph node and spleen CD169+ and spleen CD163+ macrophages. Lymph node and spleen CD169+ macrophages can be both identified as CD172a+SLA-DRhiCD80/86hiCD14intTLR2+TLR4+. On the other side, spleen CD163+ macrophages are CD172a+SLA-DRintCD80/86intCD14−/loTLR2intTLR4int. In addition, these macrophages can be subdivided based on the expression of CD11R1 or CD11R3. Lymph node CD169+ macrophages phagocytozed polystyrene microspheres more efficiently than spleen CD163+ and CD169+ macrophages. All macrophages exhibited low capacity to take up and process the soluble antigen DQ-OVA. Finally, spleen CD163+ macrophages displayed the highest ability to present lysozyme to CD4+ T cells in a secondary in vitro response, followed by lymph node and spleen CD169+ macrophages.