title: Melatonin inhibits apoptosis during early B-cell development in mouse bone marrow.
abstract: The pineal secretory product, melatonin, exerts a variety of effects on the immune system. Administration of melatonin stimulates cell-mediated immunity, particularly by inhibiting apoptosis among T lymphocytes in the thymus and inducing production of T-cell-derived cytokines. However, its possible effects on the humoral immune system are unclear. In the present study, we have examined whether melatonin may influence the in vivo development of B lymphocytes in mouse bone marrow, a process in which apoptosis is normally a prominent feature. Double immunofluorescence labeling and flow cytometry were used to quantitate phenotypically defined precursor B-cell and mature B-cell populations and their apoptotic rates in bone marrow of mice fed either melatonin-containing or control diet for 16 days from 9 wk of age. In short-term bone marrow cultures, the incidence of apoptosis among large pre-B cells, including cells expressing the lambda5 component of pre-B-cell receptor, was markedly reduced in melatonin-treated mice, associated with an increase in the absolute number of large pre-B cells in bone marrow. In contrast, apoptosis of earlier precursor B cells and mature B lymphocytes did not differ from control values. The results indicate that orally administered melatonin can substantially promote the survival of precursor B cells in mouse bone marrow. Melatonin treatment may thus boost the survival of newly formed B cells mediating humoral immunity.
authors.affiliation: Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
authors.forename: Q
authors.initials: Q
authors.lastname: Yu
authors.forename: S C
authors.initials: SC
authors.lastname: Miller
authors.forename: D G
authors.initials: DG
authors.lastname: Osmond
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002453:Cell Cycle / Q000187:drug effects / Q000276:immunology; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D019070:Cell Lineage / Q000276:immunology; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D016130:Immunophenotyping; D008550:Melatonin / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D008809:Mice, Inbred C3H; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D004247:DNA; D008550:Melatonin