Characterization of immature B cells by a novel monoclonal antibody, by turnover and by mitogen reactivity (original) (raw)
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The Journal of Immunology
Human mAbs (HumAbs) have therapeutic potential against infectious diseases and cancer. Heretofore, their production has been hampered by ethical constraints preventing the isolation of Ag-specific activated B cells by in vivo immunization. Alternatively, severe combined immune deficient (SCID) mice, transplanted i.p. with human (Hu)-PBLs, allow the in vivo stimulation of human Ab responses without the usual constraints. Unfortunately, human B cells only represent a minor fraction of the surviving graft, they are scattered all over the animal body, and thus are hard to isolate for subsequent immortalization procedures. To prevent this dispersion and to provide the human B cells with a niche for expansion and maturation, SCID mice were engrafted with Hu-PBL directly into the spleen. Simultaneously endogenous murine NK cell activity was depleted by treatment with an anti-mouse IL-2 receptor beta-chain Ab. During engraftment, human B lymphocytes became activated, divided intensely, and ...
2010
Only mature B lymphocytes can enter the lymphoid follicles of spleen and lymph nodes and thus efficiently participate in the immune response. Mature, long-lived B lymphocytes derive from short-lived precursors generated in the bone marrow. We show that selection into the mature pool is an active process and takes place in the spleen. Two populations of splenic B cells were identified as precursors for mature B cells. Transitional B cells of type 1 (T1) are recent immigrants from the bone marrow. They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen. Mature B cells can be generated from T1 or T2 B cells.
Immunity, 2000
are generated and maintained through continuous IgM signaling, and, as a result, the B1 repertoire is enriched with some antibody specificities (Bhat et al., 1992; Ar-Summary nold et al., 1994; Hardy et al., 1994). Inactivation of molecules associated with signaling through surface IgM-Using immunoglobulin heavy chain transgenic mice, we show that B cell clones reaching the long-lived pool ligand interactions (btk, Ig␣ tail, CD19, vav, PKC, PI3 kinase-p85␣, etc.) decreases the B1 significantly more are heterogeneous: some are enriched in the CD21 high compartment (mostly marginal zone [MZ]), others re-than the B2 compartment. The mature B2 population appears less enriched for side primarily in the follicles (FO). Altering the composition of the B cell receptor through N region additions certain specificities compared to B1; however, a low level of IgM receptor engagement is required for their decreases the rate of clonal production and the MZ enrichment. This process can be recapitulated by puri-development and maintenance (Cyster et al., 1996; Lam et al., 1997). Phenotypic and topographical heterogeneity fied CD21 low B cells and is due to a preferential clonal survival that requires a functional btk tyrosine kinase. exists within the mature B2 cell population with IgM lo IgD hi CD21 int CD23 hi recirculating cells located in B lymphoid We also show that generation of the MZ population is dependent on CD19. These findings suggest that the follicles (FO) in spleen and lymph nodes and IgM hi IgD lo CD21 hi CD23 lo nonrecirculating cells enriched primarily MZ B cell repertoire is positively selected and have functional implications for antigenic responses ef-in the marginal zone (MZ) of the spleen (Gray et al., 1982; Oliver et al., 1997). However, because the complex fected by B cells from this microenvironment. intrasplenic trafficking pathways are not fully understood, there is not a perfect correlation between the Introduction phenotype and topography of splenic B cell subsets. Studies in rats have shown that thoracic duct recirculat-The generation and selection of B lymphocytes to create ing cells contain MZ B cell precursors and also that a diverse and flexible repertoire that will thwart pathomemory cells colonize the marginal zone from where gens is the result of a series of developmental programs they are mobilized by a new antigen encounter (Kumaraand checkpoints (Rolink and Melchers, 1996; Goodnow, ratne and MacLennan, 1982; Liu et al., 1991).
BAFF is a survival and maturation factor for mouse B cells
European Journal of Immunology, 2002
Human B cell-activating factor (BAFF) induces mouse surface IgM + B cells of the immature type from bone marrow and of the immature types 1 and 2 from spleen, as well as of the mature type from spleen to increased longevity in tissue culture. BAFF does so polyclonally and without inducing proliferation in any of these B cell subpopulations. BAFF induces phenotypic and functional maturation of immature to mature B cells so that all immature cells loose C1qRp (AA4.1, 493) expression and type 1 immature cells up-regulate IgD, CD21 and CD23. Immature B cells of types 1 and 2, upon pre-incubation with BAFF, change their reactiveness to Ig-specific antibodies so that they no longer enter apoptosis but now proliferate. However, BAFF does not seem to overcome negative selection of developing immature B cells in vitro.
The Journal of Experimental Medicine, 2000
The B cell receptor (BCR) regulates B cell development and function through immunoglobulin (Ig)α and Igβ, a pair of membrane-bound Ig superfamily proteins, each of which contains a single cytoplasmic immunoreceptor tyrosine activation motif (ITAM). To determine the function of Igβ, we produced mice that carry a deletion of the cytoplasmic domain of Igβ (IgβΔC mice) and compared them to mice that carry a similar mutation in Igα (MB1ΔC, herein referred to as IgαΔC mice). IgβΔC mice differ from IgαΔC mice in that they show little impairment in early B cell development and they produce immature B cells that respond normally to BCR cross-linking as determined by Ca2+ flux. However, IgβΔC B cells are arrested at the immature stage of B cell development in the bone marrow and die by apoptosis. We conclude that the cytoplasmic domain Igβ is required for B cell development beyond the immature B cell stage and that Igα and Igβ have distinct biologic activities in vivo.
Journal of Experimental Medicine, 2000
The B cell receptor (BCR) regulates B cell development and function through immunoglobulin (Ig)α and Igβ, a pair of membrane-bound Ig superfamily proteins, each of which contains a single cytoplasmic immunoreceptor tyrosine activation motif (ITAM). To determine the function of Igβ, we produced mice that carry a deletion of the cytoplasmic domain of Igβ (IgβΔC mice) and compared them to mice that carry a similar mutation in Igα (MB1ΔC, herein referred to as IgαΔC mice). IgβΔC mice differ from IgαΔC mice in that they show little impairment in early B cell development and they produce immature B cells that respond normally to BCR cross-linking as determined by Ca2+ flux. However, IgβΔC B cells are arrested at the immature stage of B cell development in the bone marrow and die by apoptosis. We conclude that the cytoplasmic domain Igβ is required for B cell development beyond the immature B cell stage and that Igα and Igβ have distinct biologic activities in vivo.
Characterization of B-cell maturation in the peripheral immune system
Methods in molecular biology (Clifton, N.J.), 2004
In the periphery different populations of B cells can be identified, corresponding to subsequent stages of B-cell development. Transitional 1 B cells are recent bone marrow emigrants traveling with the blood to the spleen. Here they further develop to transitional 2 and mature B cells. Marginal zone B cells are a sessile population only found in the spleen. The distinction of these cell types is only possible by three- and four-color flow cytometry, analyzing the relative expression of several developmentally regulated markers. We describe the method for the staining of the cells and the analysis of the collected data and show examples of the results obtained in normal and mutant mice.
Early and late B-cell development in the mouse
Current Biology, 1992
A common principle in B-cell development is the stringent selection of cells expressing appropriate antibody V regions as surface receptors. Cells failing to do so appear destined to rapid death. These lifedeath decisions are mediated by signals whose nature is not yet understood but whose generation involves immunoglobulin receptor complexes on B cells and B-cell progenitors.