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Abstract
The factors regulating growth and patterning of the spleen are poorly defined. We demonstrate here that spleens from B cell-deficient mice have 10-fold reduced expression of the T zone chemokine, CCL21, a threefold reduction in T cell and dendritic cell (DC) numbers, and reduced expression of the T zone stromal marker, gp38. Using cell transfer and receptor blocking approaches, we provide evidence that B cells play a critical role in the early postnatal development of the splenic T zone. This process involves B cell expression of lymphotoxin (LT)alpha1beta2, a cytokine that is required for expression of CCL21 and gp38. Introduction of a B cell specific LTalpha transgene on to the LTalpha-deficient background restored splenic CCL21 and gp38 expression, DC numbers, and T zone size. This work also demonstrates that the role of B cells in T zone development is distinct from the effect of B cells on splenic T cell numbers, which does not require LTalpha1beta2. Therefore, B cells influence spleen T zone development by providing: (a) signals that promote T cell accumulation, and: (b) signals, including LTalpha1beta2, that promote stromal cell development and DC accumulation. Defects in these parameters may contribute to the immune defects associated with B cell deficiency in mice and humans.
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Affiliation(s)
- V N Ngo
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA
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2
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Bone Marrow and Thymus Expression of Interferon-γ Results in Severe B-Cell Lineage Reduction, T-Cell Lineage Alterations, and Hematopoietic Progenitor Deficiencies. Blood 1997. [DOI: 10.1182/blood.v89.2.583] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Interferon-γ (IFN-γ) is an immunoregulatory lymphokine that is primarily produced by T cells and natural killer cells. It has effects on T-cell, B-cell, and macrophage differentiation and maturation. We have developed transgenic mice that express elevated levels of IFN-γ mRNA and protein by inserting multiple copies of murine IFN-γ genomic DNA containing an Ig λ-chain enhancer in the first intron. The founder line carrying eight copies of this transgene has eightfold to 15-fold more IFN-γ–producing cells in the bone marrow and spleen than do nontransgenic littermates. Transgenic mice show a pronounced reduction in B-lineage cells in the bone marrow, spleen, and lymph nodes. In addition, single positive (CD4+,CD8− and CD4−,CD8+) thymocyte numbers are increased twofold, yet the number of splenic T cells is reduced by 50%. There is also a twofold to threefold decrease in the frequency and total number of myeloid progenitors in the bone marrow. Granulomatous lesions and residual degenerating cartilaginous masses are also present in the bones of these mice. Overall, our data show that the abnormal expression of IFN-γ in these transgenic mice results in multiple alterations in the immune system. These animals provide an important model to examine the role of IFN-γ expression on lymphoid and myeloid differentiation and function.
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Singer SM, Umetsu DT, McDevitt HO. High copy number I-Ab transgenes induce production of IgE through an interluekin 4-dependent mechanism. Proc Natl Acad Sci U S A 1996; 93:2947-52. [PMID: 8610148 PMCID: PMC39740 DOI: 10.1073/pnas.93.7.2947] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To better understand the role of class II major histocompatibility complex molecules in both normal and autoimmune responses, we have produced a series of I-Ab transgenic mice. One of these transgenic constructs, designated NOD.PD, has the sequence of the NOD beta chain (Abeta(g7)) except at positions 56 and 57, where Pro-Asp replaces His-Ser. Several NOD.PD transgenic lines have been produced. One line of these mice carried a very high number of copies (>50) of the NOD.PD transgene. As has been described in other mice carrying high copy numbers of I-Ab transgenes, B-cell development was abnormal. The steady state numbers of mature B cells (IgM+/IgD(hi)) in the periphery were greatly reduced in transgenic mice compared to nontransgenic littermates. Surprisingly, rather than being accompanied by a generalized hypogammaglobulinemia, this B-cell deficiency was accompanied by elevated concentrations of IgG1 and IgE in the serum. Conversely, the levels of IgG2a were reduced in transgenic mice compared to nontransgenic littermates. Because this isotype pattern was characteristic of interleukin (IL)-4-induced class-switching, we then investigated the role of IL-4 in causing the observed phenotype. We crossed the high copy number transgenic mice with an IL-4-deficient strain of mice. As expected, the elevated levels of IgE in high copy number transgenic mice were eliminated when the IL-4 gene was inactivated. However, the reduction in the number of B cells was not ameliorated. These data indicate that the primary defect caused by the transgene was to reduce the number of B cells in these mice. This reduction was accompanied by a secondary increase in IL-4 production, which drove the remaining B cells toward the production of IgGl and IgE.
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Affiliation(s)
- S M Singer
- Department of Microbiology and Immunology, Standford University Medical Center, CA 94305, USA
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Roth PE, Kurtz B, Lo D, Storb U. lambda 5, but not mu, is required for B cell maturation in a unique gamma 2b transgenic mouse line. J Exp Med 1995; 181:1059-70. [PMID: 7869028 PMCID: PMC2191911 DOI: 10.1084/jem.181.3.1059] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
gamma 2b transgenic mice have a severe B cell defect, apparently caused by strong feedback inhibition of endogenous H-gene rearrangement coupled with an inability of gamma 2b to provide the survival/maturation functions of mu. A unique gamma 2b transgenic line, named the C line, was found to permit B cell development. When the C line is crossed with a mu-membrane knockout line, gamma 2b+ B cells develop in the homozygous knockout. In contrast, a transgenic line representative of all the other gamma 2b lines is completely B cell deficient when mu-mem is deleted. Strikingly, the C phenotype is dominant in C x other gamma 2b transgenic line crosses. There is no evidence for higher gamma 2b transgene expression or other position effects on the transgene in the C mouse. The sequences of the three gamma 2b transgene copies in the C line are identical to that of the original transgene. These results have led to the conclusion that in the C line the transgene integration constitutively induces a gene whose expression can replace mu. To more clearly delineate the stage at which the altered phenotype of the C line is expressed, C mice were crossed onto a lambda 5 knockout background. In the absence of lambda 5, the C line produces no B cells. Since it was also found that gamma 2b can associate with the surrogate light chain (sL; lambda 5/Vpre-B), the crosses between C line gamma 2b mice and lambda 5 knockout mice suggest that gamma 2b/sL is required for B cell maturation in this mouse line. Thus, gamma 2b alone is unable to replace mu for pre-B cell survival/maturation; however, in combination with an unknown factor and the sL, gamma 2b can provide these nurturing functions.
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Affiliation(s)
- P E Roth
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637
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Hengstschläger M, Maizels N. Isotype exclusion in lambda 1 transgenic mice depends on transgene copy number and diminishes with down-regulation of transgene transcripts. Eur J Immunol 1995; 25:187-91. [PMID: 7843231 DOI: 10.1002/eji.1830250131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have compared expression of the endogenous kappa and transgenic lambda 1 light chains in three lines of mice carrying one, four and eight copies of a lambda 1 transgene. We have found that in very young mice, even a single rearranged transgenic lambda allele excludes expression of the endogenous kappa loci. As the lambda 1 transgenic mice age, the proportion of lambda-positive cells decreases, as has been reported by others (Neuberger et al., Nature 1989, 338:350; Pettersson et al., Nature 1990. 344:165; Hagman et al., J. Exp. Med. 1989. 169:1911; Bogen and Weiss, Eur. J. Immunol. 1991. 21:2391). The decrease in lambda-positive B cells is accompanied by an increase in kappa-positive cells. We show that the decrease in B cells bearing surface lambda immunoglobulin depends on transgene copy number and occurs most rapidly in lower copy number lines. The decrease in surface lambda expression correlates with a dramatic decrease in the level of lambda mRNA in splenic B cells. Transgene down-regulation cannot be alleviated by stimulation of splenocytes with the mitogen lipopolysaccharide. These are the first data to establish that a single copy transgene can effect isotype exclusion. In addition, these results provide strong evidence that down-regulation of transgene expression is controlled at the level of transcription, and that it is the level of expressed light chain that regulates isotype exclusion.
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Affiliation(s)
- M Hengstschläger
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven
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Lindeman GJ, Adams JM, Cory S, Harris AW. B-lymphoid to granulocytic switch during hematopoiesis in a transgenic mouse strain. Immunity 1994; 1:517-27. [PMID: 7895160 DOI: 10.1016/1074-7613(94)90094-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
B-lymphoid and myeloid development are markedly perturbed in a unique transgenic mouse strain, max 41. Pro-B, pre-B, and B lymphocytes were severely reduced but granulocytes were greatly elevated. This phenotype could be adoptively transferred with bone marrow cells. It was not alleviated by bcl-2 or myc transgenes that promote lymphocyte survival or proliferation. Bitransgenic myc/max 41 mice developed pre-B cell lymphoma. An accompanying massive granulocytosis unexpectedly proved to be clonally derived from the pre-B lymphoma cells. These observations suggest that B lymphopoiesis in max 41 mice has been diverted to granulocyte production. Since neither cell type expressed the transgene, this novel lymphomyeloid deviation probably reflects insertional alteration of a hematopoietic regulatory gene.
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MESH Headings
- Animals
- B-Lymphocytes/physiology
- Blotting, Northern
- Blotting, Southern
- Bone Marrow Transplantation/physiology
- Cell Differentiation/physiology
- Cells, Cultured
- Embryonic and Fetal Development
- Flow Cytometry
- Granulocytes/physiology
- Hematopoiesis, Extramedullary/genetics
- Hematopoiesis, Extramedullary/physiology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood
- Lymphoma, Non-Hodgkin/genetics
- Mice
- Mice, Transgenic
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Affiliation(s)
- G J Lindeman
- Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Melbourne, Australia
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Hengstschläger M, Williams M, Maizels N. A lambda 1 transgene under the control of a heavy chain promoter and enhancer does not undergo somatic hypermutation. Eur J Immunol 1994; 24:1649-56. [PMID: 8026525 DOI: 10.1002/eji.1830240729] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To identify cis-acting elements responsible for targeting somatic hypermutation to immunoglobulin variable regions, we generated transgenic mice which carry a rearranged lambda 1 gene regulated by the heavy chain intron enhancer, E mu, and the heavy chain promoter PH186.2 from the VH186.2 variable region. C57BL/6 x SJL founders were bred with C57BL/6 mice to establish a line carrying a single copy of the transgene. Somatic hypermutation was studied by generating hybridoma cell lines from mice immunized with the hapten (4-hydroxy-3-nitrophenyl)acetyl (NP) coupled to chicken gamma globulin. The immune response in this transgenic line was dominated by the endogenous VH186.2 heavy chain variable region and the transgenic lambda 1 light chain, and the transgene was actively expressed in all hybridomas analyzed. In this work we show that the transgenic V lambda 1 regions do not undergo hypermutation, despite high levels of expression, while the expressed heavy chain V regions accumulate mutations at a rate typical of the NP response in C57BL/6 mice. Thus, within the same B cell, the PH186.2 promoter in connection with E mu drives efficient expression of both a VH and a V lambda region, but only the VH is a target for somatic hypermutation. Our observations show that cis-acting sequences that activate immunoglobulin gene transcription are not sufficient to target somatic hypermutation.
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Affiliation(s)
- M Hengstschläger
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06510
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Wayne J, Suh H, Misulovin Z, Sokol KA, Inaba K, Nussenzweig MC. A regulatory role for recombinase activating genes, RAG-1 and RAG-2, in T cell development. Immunity 1994; 1:95-107. [PMID: 7534201 DOI: 10.1016/1074-7613(94)90103-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
RAG-1 and RAG-2 are developmentally regulated genes that are essential for the assembly of antigen receptors in lymphoid cells. Here we describe transgenic mice that carry RAG-1 and RAG-2 under the control of the proximal lck promoter. Persistent expression of RAG-1 and RAG-2 was associated with incomplete thymopoiesis and profoundly compromised cellular immunity. In addition, RAG transgenic mice rapidly developed lymphadenopathy, splenomegaly, and lymphocytic perivascular infiltrates. These effects required both RAG-1 and RAG-2, since mice that carried either gene exclusively were indistinguishable from wild-type controls. We propose that in addition to a previously documented role in V(D)J recombination, RAG-1 and RAG-2 expression must be properly regulated for completion of normal T cell development
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Affiliation(s)
- J Wayne
- Howard Hughes Medical Institute, Rockefeller University, New York, New York 10021
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Levinson DA, Campos-Torres J, Leder P. Molecular characterization of transgene-induced immunodeficiency in B-less mice using a novel quantitative limiting dilution polymerase chain reaction method. J Exp Med 1993; 178:317-29. [PMID: 8315387 PMCID: PMC2191084 DOI: 10.1084/jem.178.1.317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
B-less mice express a human immunoglobulin (Ig) lambda transgene that induces a severe deficiency of both immature pre-B and mature B lymphocytes. To understand this perturbation in B lymphopoiesis, we have devised a sensitive limiting dilution polymerase chain reaction assay that quantitates specific Ig rearrangements and thus quantitates B lineage cells at various stages of differentiation within unfractionated bone marrow. We find that there are significantly reduced frequencies of both VH-to-DJH and VK-to-JK rearrangements in the transgenic strain, whereas the frequency of D-to-JH rearrangements approximates that of wild type. Since Ig gene rearrangements occur in a stepwise fashion in which D-to-JH joining precedes that of VH-to-DJH and VK-to-JK, these results indicate that the major block of B lymphocyte development in the B-less strain occurs after D-to-JH rearrangement. Interestingly, sequence analysis of residual VHDJH junctions from transgenic pre-B lymphocytes reveals that an abnormally high proportion of these are out of frame and therefore nonproductive. Taken together, these data suggest that early expression of the transgenic lambda protein specifically prevents the development of a normal-sized population of precursor B lymphocytes coexpressing functional IgH. The transgene-induced immunodeficiency appears to arise by a precocious maturation process in which precursors bypass a developmental stage associated with cellular expansion.
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Affiliation(s)
- D A Levinson
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
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Ronchese F, Hausmann B. B lymphocytes in vivo fail to prime naive T cells but can stimulate antigen-experienced T lymphocytes. J Exp Med 1993; 177:679-90. [PMID: 8436906 PMCID: PMC2190947 DOI: 10.1084/jem.177.3.679] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The ability of B cells or macrophages and dendritic cells (DC) to elicit class II-restricted T cell responses in vivo was compared using a mouse chimera model. Severe combined immunodeficient (SCID) mice (H-2d), reconstituted either with T or T+B lymphocytes from (H-2d x H-2b) donors, were immunized subcutaneously with protein antigen (Ag) to induce a class II-restricted T cell response. The frequency and major histocompatibility complex restriction of the resulting Ag-specific T cells were analyzed to establish whether B cells were necessary for the induction of class II-restricted T cell responses, and to determine the cell type on which priming had occurred. The results indicated that: (a) B cells are not necessary for the induction of a class II-restricted T cell response in vivo, as the frequencies of interleukin 2 (IL-2)- or IL-3-secreting T cells induced in the presence or absence of B cells were comparable. (b) Activation of naive T cells requires presentation of Ag on DC; Ag presented only on B cells is not sufficient to elicit a response. No H-2b-restricted, IL-3-secreting cells could in fact be detected in SCID mice reconstituted with naive (H-2d x H-2b) T cells and nonimmune or antigen-primed (H-2d x H-2b) B cells. (c) Previously primed T cells are able to be stimulated by Ag presented by both B cells and DC. H-2b-restricted, IL-3-secreting cells could in fact be readily demonstrated in SCID mice reconstituted with antigen-primed (H-2d x H-2b) T and B cells. Irrespective of whether the T cells were naive or previously activated, B cells were able to respond with an Ag-specific immunoglobulin G response, indicating that B cells were functional and able to present Ag in order to receive specific T cell help. Therefore, it appears that B cells are not necessary and do not participate in the initial priming of T cells; however, Ag presented by B cells can reactivate previously primed T cells. Taken together, these data indicate that during the course of an immune response Ag is first presented to naive T cells via DC, and only subsequently primed T cells can be stimulated by Ag presented by B cells.
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Affiliation(s)
- F Ronchese
- Basel Institute for Immunology, Switzerland
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Affiliation(s)
- A Rolink
- Basel Institute for Immunology, Switzerland
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