title: Profound reduction of mature B cell numbers, reactivities and serum Ig levels in mice which simultaneously carry the XID and CD40 deficiency genes.
abstract: It has been known for some time that single mutant nude or CD40T mice have apparently normal numbers of cells in the precursor compartments of bone marrow and the mature B cell compartments of the periphery. X-linked immunodeficiency (XID) mice are deficient only in some of the sIgM+sIgD+ B cells. We have investigated further the contributions of the xid mutation, of the T cell deficiency of nude of the inability of CD40T cells to cooperate with T cells in the generation of the precursor and the mature B cell compartments in mice. Double mutant XID/nu and XID/CD40T mice have precursor B cell compartments that are no more deficient than the single mutant XID mice. However, the peripheral B cell compartments of both XID/mu and XID/CD40T are even more deficient than those of single mutant XID mice. While 10% of the peripheral B cells of wild-type or CD40T, one-third of XID and half of XID/nu mice turn over rapidly, as many as three-quarters of those in XID/CD40T are short-lived. Total numbers of sIgM+sIgD+ B cells in the spleen are at best 10-15% of normal mice at 6-8 weeks of age in XID, XID/nu and XID/CD40T mice. They remain that low at 3 months of age in XID/CD40T mice, while in XID mice these peripheral B cells slowly build up in numbers with age. As expected, double mutant XID/CD40T mice do not respond to the T-dependent antigen keyhole limpet hemocyanin. Only the responses to the T-independent type I antigen, TNP-lipopolysaccharide (LPS), appear to be normal. In vitro, their splenic B cells respond poorly to LPS or to IgM-specific antibody in either the absence or presence of cytokines. Most notably, serum IgM, IgG2b or IgG3 levels are severely depressed, while IgG1, IgG2a and IgA levels are < 10 micrograms/ml. These results suggest a model of mature B cell development in which the peripheral, mature B cell compartments are generated in two parallel, not tandemly organized pathways. They could be selected and/or stimulated at the transition from immature to mature B cells: in btk controlled or in CD40 controlled ways.
authors.affiliation: Basel Institute for Immunology, Switzerland.
authors.forename: Y
authors.initials: Y
authors.lastname: Oka
authors.forename: A G
authors.initials: AG
authors.lastname: Rolink
authors.forename: J
authors.initials: J
authors.lastname: Andersson
authors.forename: M
authors.initials: M
authors.lastname: Kamanaka
authors.forename: J
authors.initials: J
authors.lastname: Uchida
authors.forename: T
authors.initials: T
authors.lastname: Yasui
authors.forename: T
authors.initials: T
authors.lastname: Kishimoto
authors.forename: H
authors.initials: H
authors.lastname: Kikutani
authors.forename: F
authors.initials: F
authors.lastname: Melchers
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens / Q000235:genetics*; D005260:Female; D007136:Immunoglobulins / Q000097:blood* / Q000235:genetics*; D007153:Immunologic Deficiency Syndromes / Q000235:genetics*; D008213:Lymphocyte Activation / Q000235:genetics*; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000235:genetics*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008819:Mice, Nude; D014960:X Chromosome / Q000235:genetics*
chemical_list: D019013:CD40 Antigens; D007136:Immunoglobulins