Intracellular localization of myeloperoxidase in murine peritoneal B-lymphocytes and macrophages

• Published in: Cellular immunology 2013-01, Vol.281 (1), p.27-30
• Main Authors: Henrique de Araujo, Tomaz, Okada, Sabrina Sayori, Ghosn, Eliver Eid Bou, Taniwaki, Noemi Nosomi, Rodrigues, Maria Rita, Rogerio de Almeida, Sandro, Mortara, Renato Arruda, Russo, Momtchilo, Campa, Ana, Albuquerque, Renata Chaves
• Format: Article
• Language: English
• Subjects: Animals; Ascitic Fluid - cytology; B-cell; B-Lymphocytes - enzymology; B-Lymphocytes - immunology; B-Lymphocytes - metabolism; B1-a lymphocytes; Cell Nucleus - metabolism; Cytoplasmic Granules - metabolism; Cytoplasmic Vesicles - metabolism; Electron microscopy; Flow Cytometry; Hypochlorous Acid - metabolism; Macrophages - enzymology; Macrophages - immunology; Macrophages - metabolism; Mice; Microscopy, Confocal; Mitochondria - metabolism; MPO; Neutrophils - enzymology; Neutrophils - immunology; Neutrophils - metabolism; Peritoneal cavity; Peritoneal Cavity - cytology; Peroxidase - immunology; Peroxidase - metabolism
• ISSN: 0008-8749; 1090-2163
• DOI: 10.1016/j.cellimm.2013.01.002

► Myeloperoxidase is present in mice peritoneal macrophages and lymphocytes. ► B-1a lymphocytes contain MPO. ► MPO is distributed in cytoplasm, mitochondria and nucleus of mice peritoneal cells. Generation of hypochlorous acid (HOCl), an important microbicidal agent, is considered to be the main function of myeloperoxidase (MPO), an enzyme present in phagocytes. High amounts of MPO are present in neutrophil azurophilic granules, which are mobilized into the phagolysosome vacuole during phagocytosis. MPO is also present in monocytes and macrophages, although to a lesser degree than in neutrophils. In the present study, we investigated the distribution of MPO in murine peritoneal cells using flow cytometry, confocal microscopy (CM) and transmission electron microscopy (TEM). MPO was observed in macrophages, and surprisingly, we detected MPO in B lymphocytes, specifically in B1-a. MPO was present in cytoplasmic granules, vesicles, mitochondria and the nucleus of murine peritoneal cells. Together, these findings suggest that, in addition to its known microbicidal activity, MPO has a myriad of other unanticipated cellular functions.