title: Ceruloplasmin expression by human peripheral blood lymphocytes: a new link between immunity and iron metabolism.
abstract: Ceruloplasmin (CP) is a multicopper oxidase involved in the acute phase reaction to stress. Although the physiological role of CP is uncertain, its role in iron (Fe) homeostasis and protection against free radical-initiated cell injury has been widely documented. Previous studies showed the existence of two molecular isoforms of CP: secreted CP (sCP) and a membrane glycosylphosphatidylinositol (GPI)-anchored form of CP (GPI-CP). sCP is produced mainly by the liver and is abundant in human serum whereas GPI-CP is expressed in mammalian astrocytes, rat leptomeningeal cells, and Sertolli cells. Herein, we show using RT-PCR that human peripheral blood lymphocytes (huPBL) constitutively express the transcripts for both CP molecular isoforms previously reported. Also, expression of CP in huPBL is demonstrated by immunofluorescence with confocal microscopy and flow cytometry analysis using cells isolated from healthy blood donors with normal Fe status. Importantly, the results obtained show that natural killer cells have a significantly higher CP expression compared to all other major lymphocyte subsets. In this context, the involvement of lymphocyte-derived CP on host defense processes via its anti/prooxidant properties is proposed, giving further support for a close functional interaction between the immune system and the Fe metabolism.
authors.affiliation: Instituto Nacional de Saúde Dr. Ricardo Jorge, IP (INSA), Lisboa, Portugal.
authors.forename: João
authors.initials: J
authors.lastname: Banha
authors.forename: Liliana
authors.initials: L
authors.lastname: Marques
authors.forename: Rita
authors.initials: R
authors.lastname: Oliveira
authors.forename: Maria de Fátima
authors.initials: Mde F
authors.lastname: Martins
authors.forename: Eleonora
authors.initials: E
authors.lastname: Paixão
authors.forename: Dina
authors.initials: D
authors.lastname: Pereira
authors.forename: Rui
authors.initials: R
authors.lastname: Malhó
authors.forename: Deborah
authors.initials: D
authors.lastname: Penque
authors.forename: Luciana
authors.initials: L
authors.lastname: Costa
mesh_terms: D000328:Adult; D001483:Base Sequence; D015415:Biomarkers / Q000032:analysis; D002460:Cell Line; D002570:Ceruloplasmin / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D007109:Immunity; D007501:Iron / Q000378:metabolism*; D008214:Lymphocytes / Q000201:enzymology* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data
chemical_list: D015415:Biomarkers; D007501:Iron; D002570:Ceruloplasmin