title: Hematopoietic stem cell functional failure in interleukin-2-deficient mice.
abstract: The effects of interleukin-2 (IL-2) deficiency on hematopoiesis were tested by measuring cellular compositions in peripheral blood, spleen, thymus, and bone marrow of 3- to 5-month-old gene-targeted Il2 null (Il2(-/-)) mice using the Advia 120 Hematology system and fluorescence-activated cell staining (FACS). Il2(-/-) mice developed hematological failure and autoimmune responses, showing variable but significant degrees of anemia, lymphocytopenia, thrombocytopenia, splenomegaly, thymus involution, and weight loss. Surprisingly, Il2(-/-) mice had normal numbers of bone marrow cells (BMCs) with increased numbers of Lin(-)Kit(+)Sca1(+)CD34(-) and Lin(-)Kit(+)Sca1(+)CD34(+) cells that are normally associated with hematopoietic stem cells (HSCs) and progenitor cells. Day-12 colony-forming units-spleen cells were slightly reduced in Il2(-/-) mice. When Il2(-/-) and Il2(+/+) mice were compared for long-term HSC function in vivo in the competitive repopulation assay, BMCs from Il2(-/-) donors had 10- to 20-fold less HSC repopulating ability, which affected both myeloid and lymphoid cell lineages. Thus, HSCs from Il2(-/-) mice can proliferate normally but are functionally defective for reconstituting lethally irradiated recipients.
authors.affiliation: Hematology Branch, National Heart, Lung and Blood Institute, Bethesda, MD 20892-1652, USA. chenji@nhlbi.nih.gov
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: C M
authors.initials: CM
authors.lastname: Astle
authors.forename: D E
authors.initials: DE
authors.lastname: Harrison
mesh_terms: D000818:Animals; D015551:Autoimmunity; D001773:Blood Cells / Q000166:cytology; D001854:Bone Marrow Cells / Q000276:immunology; D002452:Cell Count; D005434:Flow Cytometry; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000473:pathology / Q000502:physiology*; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000172:deficiency* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D010641:Phenotype; D013154:Spleen / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology
chemical_list: D007376:Interleukin-2