Plasma membrane damage by environmental materials enhances cell-cell fusion and impairs defense functions of macrophages.

Introduction: Many environmental materials can activate macrophages and trigger inflammatory responses. However, whether and how these exposures alter macrophage function in host defense remains elusive. Methods: Bone marrow-derived macrophages were treated with various environmental materials, including laundry detergent, and their membrane damage was measured by Annexin V staining. Alterations in macrophage function were assessed by cell-cell fusion, in vitro phagocytosis, and in vivo clearance of Candida albicans. Results and Discussion: Many environmental hazards damage the plasma membranes of macrophages. This damage decreases macrophage phagocytosis but elevates cell-cell fusion. In vivo, airway exposure to laundry detergent impairs the recruitment of macrophages and other myeloid cells to the lung and dramatically dampens protective TH1 and TH17 cell responses, thereby increasing susceptibility to Candida infection in mice. Overall, our data indicate that exposure to environmental materials compromises macrophage membrane integrity and impairs host defense. These findings may aid in developing effective preventive and therapeutic strategies.