title: A dual role for Src homology 2 domain-containing inositol-5-phosphatase (SHIP) in immunity: aberrant development and enhanced function of b lymphocytes in ship -/- mice.
abstract: In this report, we demonstrate that the Src homology 2 domain-containing inositol-5-phosphatase (SHIP) plays a critical role in regulating both B cell development and responsiveness to antigen stimulation. SHIP(-/-) mice exhibit a transplantable alteration in B lymphoid development that results in reduced numbers of precursor B (fraction C) and immature B cells in the bone marrow. In vitro, purified SHIP(-/)- B cells exhibit enhanced proliferation in response to B cell receptor stimulation in both the presence and absence of Fcgamma receptor IIB coligation. This enhancement is associated with increased phosphorylation of both mitogen-activated protein kinase and Akt, as well as with increased survival and cell cycling. SHIP(-/)- mice manifest elevated serum immunoglobulin (Ig) levels and an exaggerated IgG response to the T cell-independent type 2 antigen trinitrophenyl Ficoll. However, only altered B cell development was apparent upon transplantation into nonobese diabetic-severe combined immunodeficient (NOD/SCID) mice. The in vitro hyperresponsiveness, together with the in vivo findings, suggests that SHIP regulates B lymphoid development and antigen responsiveness by both intrinsic and extrinsic mechanisms.
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada.
authors.forename: C D
authors.initials: CD
authors.lastname: Helgason
authors.forename: C P
authors.initials: CP
authors.lastname: Kalberer
authors.forename: J E
authors.initials: JE
authors.lastname: Damen
authors.forename: S M
authors.initials: SM
authors.lastname: Chappel
authors.forename: N
authors.initials: N
authors.lastname: Pineault
authors.forename: G
authors.initials: G
authors.lastname: Krystal
authors.forename: R K
authors.initials: RK
authors.lastname: Humphries
mesh_terms: D000818:Animals; D017209:Apoptosis; D001402:B-Lymphocytes / Q000276:immunology*; D001854:Bone Marrow Cells / Q000276:immunology; D016026:Bone Marrow Transplantation; D002453:Cell Cycle; D005362:Ficoll / Q000031:analogs & derivatives / Q000276:immunology; D005434:Flow Cytometry; D007111:Immunity, Cellular; D007075:Immunoglobulin M; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D051379:Mice; D016688:Mice, Inbred NOD; D008817:Mice, Mutant Strains; D016513:Mice, SCID; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009196:Myeloproliferative Disorders; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000276:immunology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011947:Receptors, Antigen, B-Cell; D015398:Signal Transduction; D013154:Spleen / Q000166:cytology / Q000276:immunology; D014301:Trinitrobenzenes / Q000276:immunology; D018909:src Homology Domains / Q000276:immunology*
chemical_list: D007075:Immunoglobulin M; D011518:Proto-Oncogene Proteins; D011947:Receptors, Antigen, B-Cell; C020529:TNP-ficoll; D014301:Trinitrobenzenes; D005362:Ficoll; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D010744:Phosphoric Monoester Hydrolases; C098706:INPPL1 protein, human; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases