RESUMO
Myeloperoxidase (MPO) is an important enzyme in the front-line protection against microorganisms. In peripheral blood, it is accepted that MPO is only produced by myeloid-lineage cells. Thus, MPO presence is unexpected in lymphocytes. We showed recently that B1-lymphocytes from mice have MPO. Here, we showed that subsets of human peripheral B, CD4(+) and CD8(+) T lymphocytes express MPO. The content of MPO in lymphocytes was very low compared to neutrophils/monocytes with a preferential distribution in the nucleus and perinuclear region. Also, we performed a MPO mRNA expression analysis from human blood cells derived from microarray raw data publicly available, showing that MPO is modulated in infectious disease. MPO was increased in CD4(+) T lymphocytes from HIV chronic infection and in CD8(+) T lymphocytes from HCV-positive patients. Our study points out MPO as a multifunctional protein due to its subcellular localization and expression modulation in lymphocytes indicating alternative unknown functions for MPO in lymphocytes.
Assuntos
Linfócitos B/enzimologia , Linfócitos T CD4-Positivos/enzimologia , Linfócitos T CD8-Positivos/enzimologia , Peroxidase/biossíntese , Linfócitos B/imunologia , Western Blotting , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Separação Celular , Citometria de Fluxo , Infecções por HIV/enzimologia , Infecções por HIV/imunologia , Hepatite C/enzimologia , Hepatite C/imunologia , Humanos , Imunofenotipagem , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Análise de Sequência com Séries de Oligonucleotídeos , Peroxidase/imunologia , Reação em Cadeia da Polimerase em Tempo RealRESUMO
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.
