title: MC(1) receptors are constitutively expressed on leucocyte subpopulations with antigen presenting and cytotoxic functions.
abstract: The expression of melanocortin MC(1) receptors on human peripheral lymphocyte subsets was analysed by flow cytometry using rabbit antibodies selective for the human MC(1) receptor and a panel of monoclonal antibodies against lymphocyte differentiation markers. The MC(1) receptor was found to be constitutively expressed on monocytes/macrophages, B-lymphocytes, natural killer (NK) cells and a subset of cytotoxic T-cells. Interestingly T-helper cells appeared to be essentially devoid of MC(1) receptors. The results were confirmed by RT-PCR which indicated strong expression of MC(1) receptor mRNA in CD14(+), CD19(+) and CD56(+) cells. However, only a faint RT-PCR signal was seen in CD3(+) cells, in line with the immuno-staining results that indicated that only part of the CD3(+) cells (i.e. some of the CD8(+) cells) expressed the MC(1) receptor. The MC(1) receptors' constitutive expression on immune cells with antigen-presenting and cytotoxic functions implies important roles for the melanocortic system in the modulation of immune responses.
authors.affiliation: Department of Rheumatology, Umeå University, Umeå, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Neumann Andersen
authors.forename: O
authors.initials: O
authors.lastname: Nagaeva
authors.forename: I
authors.initials: I
authors.lastname: Mandrika
authors.forename: R
authors.initials: R
authors.lastname: Petrovska
authors.forename: R
authors.initials: R
authors.lastname: Muceniece
authors.forename: L
authors.initials: L
authors.lastname: Mincheva-Nilsson
authors.forename: J E
authors.initials: JE
authors.lastname: Wikberg
mesh_terms: D000328:Adult; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology* / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D007962:Leukocytes / Q000276:immunology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D018043:Receptors, Corticotropin / Q000235:genetics* / Q000378:metabolism*; D044101:Receptors, Melanocortin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D018043:Receptors, Corticotropin; D044101:Receptors, Melanocortin