Proinflammatory clearance of apoptotic neutrophils induces an IL-12lowIL-10high regulatory phenotype in macrophages

AA Filardy, DR Pires, MP Nunes, CM Takiya… - The Journal of …, 2010 - journals.aai.org
AA Filardy, DR Pires, MP Nunes, CM Takiya, CG Freire-de-Lima, FL Ribeiro-Gomes
The Journal of Immunology, 2010journals.aai.org
Clearance of apoptotic exudate neutrophils (efferocytosis) induces either pro-or anti-
inflammatory responses in mouse macrophages depending on host genetic background. In
this study, we investigated whether neutrophil efferocytosis induces a stable macrophage
phenotype that could be recalled by late restimulation with LPS. Bone marrow-derived
macrophages previously stimulated by pro-but not anti-inflammatory neutrophil efferocytosis
expressed a regulatory/M2b phenotype characterized by low IL-12 and high IL-10 …
Abstract
Clearance of apoptotic exudate neutrophils (efferocytosis) induces either pro-or anti-inflammatory responses in mouse macrophages depending on host genetic background. In this study, we investigated whether neutrophil efferocytosis induces a stable macrophage phenotype that could be recalled by late restimulation with LPS. Bone marrow-derived macrophages previously stimulated by pro-but not anti-inflammatory neutrophil efferocytosis expressed a regulatory/M2b phenotype characterized by low IL-12 and high IL-10 production following restimulation, increased expression of LIGHT/TNF superfamily 14, Th2-biased T cell responses, and permissive replication of Leishmania major. Induction of regulatory/M2b macrophages required neutrophil elastase activity and was partially dependent on TLR4 signaling. These results suggested that macrophage differentiation to a regulatory phenotype plays a role in resolution of inflammation but could contribute to increased humoral Ab responses and parasite persistence in the infected host.
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