51
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Cunnion KM, Benjamin DK, Hester CG, Frank MM. Role of complement receptors 1 and 2 (CD35 and CD21), C3, C4, and C5 in survival by mice of staphylococcus aureus bacteremia. ACTA ACUST UNITED AC 2004; 143:358-65. [PMID: 15192652 DOI: 10.1016/j.lab.2004.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Complement-mediated opsonization and phagocytosis of encapsulated serotype 5 Staphylococcus aureus are essential to host defense. We describe the effects of complement depletion and deficiencies of C4, C5, and complement receptors 1 and 2 on mouse survival after intravenous exposure to S aureus. Depletion of complement proteins in C57BL/6 mice with the use of cobra-venom factor decreased survival compared with that of controls after the induction of bacteremia with mucoid (90% mortality), encapsulated (73%), and unencapsulated (59%) S aureus strains. In this model complement is even more important in the control of infection with encapsulated S aureus (80% of clinical isolates) than in the control of infection by unencapsulated strains. C4-deficient mice demonstrated similar mortality from bacteremia caused by encapsulated S aureus compared with controls, suggesting that in the unimmunized animal the alternative complement pathway contributes more to control of bacteremia caused by encapsulated S aureus than the classical complement pathway or mannan-binding lectin pathway. C5-deficient mice (B10.D2-H2(d) H2-T18(c) Hc(0)/oSnJ) showed similar mortality when subjected to bacteremia caused by encapsulated S aureus compared with C5-sufficient (B10.D2-Hc(1) H2(d) H2-T18(c)/nSnJ) mice, suggesting that in this model the anaphylatoxin C5a and the late complement cascade are not critical to survival of bacteremia induced with the use of these strains. However, C5-deficient mice depleted of C3 with the use of cobra-venom factor had 60% decreased survival compared with untreated C5-deficient mice with bacteremia induced by encapsulated S aureus, suggesting that in this model C3 is more critical than C5 in controlling S aureus bacteremia. Complement receptor 1 (CD35) is the primary receptor for the opsonin C3b. Mice deficient in CD35/CD21 showed a 67% decrease in survival compared with normal mice, suggesting that CD35/CD21 is of major importance in the control of S aureus-induced bacteremia.
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Affiliation(s)
- Kenji M Cunnion
- Department of Pediatrics and Duke Clinical Research Institue, Duke University Medical Center, Durham, NC, USA.
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52
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Mao C, Jiang L, Melo-Jorge M, Puthenveetil M, Zhang X, Carroll MC, Imanishi-Kari T. T cell-independent somatic hypermutation in murine B cells with an immature phenotype. Immunity 2004; 20:133-44. [PMID: 14975236 DOI: 10.1016/s1074-7613(04)00019-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2003] [Revised: 12/15/2003] [Accepted: 12/17/2003] [Indexed: 11/18/2022]
Abstract
Somatic hypermutation contributes to the generation of antibody diversity and is strongly associated with the maturation of antigen-specific immune responses. We asked whether somatic hypermutation also plays a role in the generation of the murine immunoglobulin repertoire during B cell development. To facilitate identification of somatic mutations, we examined mouse systems in which only antibodies expressing lambda1, lambda2, and lambdax light chains can be generated. Somatic mutations were found in cells, which, by surface markers, RAG expression, and rapid turnover, had the phenotype of immature B cells. In addition, expression of AID was detected in these cells. The mutations were limited to V regions and were localized in known hotspots. Mutation frequency was not diminished in the absence of T cells. Our results support the idea that somatic hypermutation can occur in murine immature B cells and may represent a mechanism for enlarging the V gene repertoire.
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Affiliation(s)
- Changchuin Mao
- Department of Pathology and Program in Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
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53
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Mongini PKA, Jackson AE, Tolani S, Fattah RJ, Inman JK. Role of Complement-Binding CD21/CD19/CD81 in Enhancing Human B Cell Protection from Fas-Mediated Apoptosis. THE JOURNAL OF IMMUNOLOGY 2003; 171:5244-54. [PMID: 14607925 DOI: 10.4049/jimmunol.171.10.5244] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Defective expression of Fas leads to B cell autoimmunity, indicating the importance of this apoptotic pathway in eliminating autoreactive B cells. However, B cells with anti-self specificities occasionally escape such regulation in individuals with intact Fas, suggesting ways of precluding this apoptosis. Here, we examine whether coligation of the B cell Ag receptor (BCR) with the complement (C3)-binding CD21/CD19/CD81 costimulatory complex can enhance the escape of human B cells from Fas-induced death. This was warranted given that BCR-initiated signals induce resistance to Fas apoptosis, some (albeit not all) BCR-triggered events are amplified by coligation of BCR and the co-stimulatory complex, and several self Ags targeted in autoimmune diseases effectively activate complement. Using a set of affinity-diverse surrogate Ags (receptor-specific mAb:dextran conjugates) with varying capacity to engage CD21, it was established that BCR:CD21 coligation lowers the BCR engagement necessary for inducing protection from Fas apoptosis. Enhanced protection was associated with altered expression of several molecules known to regulate Fas apoptosis, suggesting a unique molecular model for how BCR:CD21 coligation augments protection. BCR:CD21 coligation impairs the generation of active fragments of caspase-8 via dampened expression of membrane Fas and augmented expression of FLIP(L). This, in turn, diminishes the generation of cells that would be directly triggered to apoptosis via caspase-8 cleavage of caspase 3 (type I cells). Any attempt to use the mitochondrial apoptotic protease-activating factor 1 (Apaf-1)-dependent pathway for apoptosis (as type II cells) is further blocked because BCR:CD21 coligation promotes up-regulation of the mitochondrial antiapoptotic molecule, Bcl-2.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adjuvants, Immunologic/metabolism
- Adjuvants, Immunologic/physiology
- Adolescent
- Antibodies, Monoclonal/pharmacology
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Antigens, CD19/metabolism
- Antigens, CD19/physiology
- Apoptosis/immunology
- Apoptosis Regulatory Proteins
- B-Lymphocytes/cytology
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Binding Sites/immunology
- CD40 Antigens/pharmacology
- CD40 Ligand/pharmacology
- Carrier Proteins/biosynthesis
- Caspase 8
- Caspases/biosynthesis
- Caspases/metabolism
- Cell Survival/immunology
- Cells, Cultured
- Child
- Child, Preschool
- Co-Repressor Proteins
- Complement C3/metabolism
- DNA Fragmentation/immunology
- Fas Ligand Protein
- Humans
- Intracellular Signaling Peptides and Proteins
- Ligands
- Macromolecular Substances
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/metabolism
- Membrane Proteins/metabolism
- Membrane Proteins/physiology
- Molecular Chaperones
- Nuclear Proteins/biosynthesis
- Protein Binding/immunology
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Complement 3d/metabolism
- Receptors, Complement 3d/physiology
- TNF-Related Apoptosis-Inducing Ligand
- Tetraspanin 28
- Tumor Necrosis Factor-alpha/biosynthesis
- bcl-X Protein
- fas Receptor/biosynthesis
- fas Receptor/immunology
- fas Receptor/metabolism
- fas Receptor/physiology
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Affiliation(s)
- Patricia K A Mongini
- Department of Rheumatology, Hospital for Joint Diseases, New York, NY 10003, USA.
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54
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Andrews T, Sullivan KE. Infections in patients with inherited defects in phagocytic function. Clin Microbiol Rev 2003; 16:597-621. [PMID: 14557288 PMCID: PMC207096 DOI: 10.1128/cmr.16.4.597-621.2003] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Patients with defects in phagocytic function are predisposed to intracellular microorganisms and typically have early dissemination of the infection. Recognition of the underlying disorder and aggressive antimicrobial therapy has been beneficial for the patients. Improved understanding of the pathophysiology has also affected patient management by allowing specific, targeted immunomodulatory intervention. The disorders described in this review are not common but have had a significant impact on our understanding of the role of phagocytic cells in host defense. Conversely, understanding the role of the neutrophil and macrophage in infection has benefited not just the patients described in this review but also other patients with similar disease processes.
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Affiliation(s)
- Timothy Andrews
- Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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55
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Haberman AM, Shlomchik MJ. Reassessing the function of immune-complex retention by follicular dendritic cells. Nat Rev Immunol 2003; 3:757-64. [PMID: 12949499 DOI: 10.1038/nri1178] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The close association of follicular dendritic cells (FDCs) and germinal-centre B cells has fostered the idea that B-cell recognition of retained antigen that is presented on the surface of FDCs is important for affinity maturation and memory B-cell development. We argue that the retention of immune complexes is not required for germinal-centre development, affinity maturation and memory B-cell maintenance. Instead, it is probable that FDCs support B-cell proliferation and differentiation in a non-specific manner. Other potential roles of immune complexes retained by FDCs are discussed.
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Affiliation(s)
- Ann M Haberman
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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56
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Rossbacher J, Shlomchik MJ. The B cell receptor itself can activate complement to provide the complement receptor 1/2 ligand required to enhance B cell immune responses in vivo. J Exp Med 2003; 198:591-602. [PMID: 12925675 PMCID: PMC2194168 DOI: 10.1084/jem.20022042] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
B cells express complement receptors (CRs) that bind activated fragments of C3 and C4. Immunized CR knockout (KO) mice have lower antibody titers and smaller germinal centers (GCs), demonstrating the importance of CR signals for the humoral immune response. CR ligands were thought to be generated via complement fixation mediated by preexisting "natural" IgM or early Ab from inefficiently activated B cells. This concept was recently challenged by a transgenic (Tg) mouse model that lacks circulating antibody but still retains membrane IgM (mIgM) and mounts normal immune responses. To test whether CR ligands could be generated by the B cell receptor (BCR) itself, we generated similar mice carrying a mutated mIgM that was defective in C1q binding. We found that B cells from such mutant mice do not deposit C3 on B cells upon BCR ligation, in contrast to B cells from mIgM mice. This has implications for the immune response: the mutant mice have smaller GCs than mIgM mice, and they are particularly deficient in the maintenance of the GC response. These results demonstrate a new BCR-dependent pathway that is sufficient and perhaps necessary to provide a CR1/2 ligand that promotes efficient B cell activation.
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Affiliation(s)
- Joerg Rossbacher
- Serction of Immunobiology and Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520-8035, USA
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57
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Keşmir C, De Boer RJ. A spatial model of germinal center reactions: cellular adhesion based sorting of B cells results in efficient affinity maturation. J Theor Biol 2003; 222:9-22. [PMID: 12699731 DOI: 10.1016/s0022-5193(03)00010-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Affinity maturation of humoral responses to T-cell-dependent antigens occurs in germinal centers (GC). In GCs antigen-specific B cells undergo rounds of somatic mutations that alter their affinity. High-affinity mutants take over GCs very soon after they appear; the replacement rate is as high as 4 per day (Radmacher et al., Immunol. Cell Biol. 76 (1998) 373). To gain more insight into this selection process, we present a spatial model of GC reactions, where B cells compete for survival signals from follicular dendritic cells (FDC). Assuming that high-affinity B cells have increased cellular adhesion to FDCs, we obtain an affinity-based sorting of B cells on the FDC. This sorting imposes a very strong selection and therefore results in a winner-takes-all behavior. By comparing our sorting model with "affinity-proportional selection models", we show that this winner-takes-all selection is in fact required to account for the fast rates at which high affinity mutants take over GCs. Another important feature of in vivo GC reactions is that they are non-mixed, i.e. GCs contain either no high-affinity cells at all or they are dominated by high-affinity cells. We here show that this all-or-none behavior can be obtained if B cells are sorted based on their affinity on the FDC surface. Affinity-proportional selection models, in contrast, always produce mixed GCs.
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Affiliation(s)
- Can Keşmir
- Department of Theoretical Biology, Utrecht University, Padualaan 8, 3584-CH, Utrecht, The Netherlands.
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58
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Pihlgren M, Tougne C, Bozzotti P, Fulurija A, Duchosal MA, Lambert PH, Siegrist CA. Unresponsiveness to lymphoid-mediated signals at the neonatal follicular dendritic cell precursor level contributes to delayed germinal center induction and limitations of neonatal antibody responses to T-dependent antigens. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:2824-32. [PMID: 12626532 DOI: 10.4049/jimmunol.170.6.2824] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The factors limiting neonatal and infant IgG Ab responses to T-dependent Ags are only partly known. In this study, we assess how these B cell responses are influenced by the postnatal development of the spleen and lymph node microarchitecture. When BALB/c mice were immunized with alum-adsorbed tetanus toxoid at various stages of their immune development, a major functional maturation step for induction of serum IgG, Ab-secreting cells, and germinal center (GC) responses was identified between the second and the third week of life. This correlated with the development of the follicular dendritic cell (FDC) network, as mature FDC clusters only appeared at 2 wk of age. Adoptive transfer of neonatal splenocytes into adult SCID mice rapidly induced B cell follicles and FDC precursor differentiation into mature FDC, indicating effective recruitment and signaling capacity of neonatal B cells. In contrast, adoptive transfer of adult splenocytes into neonatal SCID mice induced primary B cell follicles without any differentiation of mature FDC and failed to correct limitations of tetanus toxoid-induced GC. Thus, unresponsiveness to lymphoid-mediated signals at the level of neonatal FDC precursors delays FDC maturation and GC induction, thus limiting primary Ab-secreting cell responses to T-dependent Ags in early postnatal life.
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MESH Headings
- Aging/immunology
- Animals
- Animals, Newborn/growth & development
- Animals, Newborn/immunology
- Antibodies, Bacterial/biosynthesis
- Antibody-Producing Cells/cytology
- Antibody-Producing Cells/metabolism
- B-Lymphocyte Subsets/cytology
- B-Lymphocyte Subsets/immunology
- Cell Differentiation/immunology
- Cell Movement/immunology
- Chemokine CXCL13
- Chemokines, CXC/physiology
- Dendritic Cells, Follicular/cytology
- Dendritic Cells, Follicular/immunology
- Female
- Germinal Center/cytology
- Germinal Center/immunology
- Haptens/immunology
- Immune Tolerance/immunology
- Lymphocyte Subsets/cytology
- Lymphocyte Subsets/immunology
- Mice
- Mice, Inbred BALB C
- Mice, SCID
- Ovalbumin/immunology
- Receptors, CXCR5
- Receptors, Chemokine
- Receptors, Cytokine/physiology
- Signal Transduction/immunology
- Stem Cells/cytology
- Stem Cells/immunology
- Tetanus Toxoid/immunology
- Trinitrobenzenes/immunology
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Affiliation(s)
- Maria Pihlgren
- Department of Pathology, World Health Organization Collaborating Center for Vaccinology and Neonatal Immunology, University of Geneva, Geneva, Switzerland.
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59
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60
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La Flamme AC, MacDonald AS, Huxtable CR, Carroll M, Pearce EJ. Lack of C3 affects Th2 response development and the sequelae of chemotherapy in schistosomiasis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:470-6. [PMID: 12496433 DOI: 10.4049/jimmunol.170.1.470] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The role of the third component of complement (C3) during schistosome infection was investigated using mice deficient in C3. While no effect was observed 8 wk after infection on worm development or liver pathology, Ag-specific Th2-associated cytokine production (IL-13, IL-5, IL-6, and IL-10) was significantly reduced, and IFN-gamma production was enhanced in the absence of C3. IgG1 and IgE, but not IgG2a or IgM, Ab responses were also significantly impaired in infected C3(-/-) mice, suggesting that C3 may play a role in IL-4-mediated Th2 response enhancement during schistosome infection. Furthermore, C3-deficient mice could not effectively clear adult worms after praziquantel (PZQ) treatment and suffered increased morbidity due to the overproduction of proinflammatory mediators following drug administration. However, the ischemic liver damage that normally accompanies PZQ administration in infected wild-type mice was substantially reduced in treated C3-deficient mice, probably due to the absence of dead or dying worms in the livers of these animals. Together these results indicate that C3 enhances Th2 responses during schistosome infection, potentiates PZQ-mediated parasite clearance, and reduces chemotherapy-induced proinflammatory mediator production.
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Affiliation(s)
- Anne Camille La Flamme
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
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61
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Kanayama N, Kimoto T, Todo K, Nishikawa Y, Hikida M, Magari M, Cascalho M, Ohmori H. B cell selection and affinity maturation during an antibody response in the mouse with limited B cell diversity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:6865-74. [PMID: 12471119 DOI: 10.4049/jimmunol.169.12.6865] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The quasi-monoclonal mouse has limited B cell diversity, whose major (approximately 80%) B cell Ag receptors are comprised of the knockin V(H) 17.2.25 (V(H)T)-encoded H chain and the lambda1 or lambda2 L chain, thereby being specific for 4-hydroxy-3-nitrophenylacetyl. The p-nitrophenylacetyl (pNP) was found to be a low affinity analog of nitrophenylacetyl. We examined affinity maturation of anti-pNP IgG by analyzing mAbs obtained from quasi-monoclonal mice that were immunized with this low affinity Ag. The results are: 1) Although V(H)T/lambda1 and V(H)T/lambda2 IgM were equally produced, V(H)T/lambda2 IgG almost exclusively underwent affinity maturation toward pNP. 2) A common mutation in complementarity-determining region 3 of V(H)T (T313A) mainly contributed to generating the specificity for pNP. 3) Because mutated V(H)T-encoded gamma-chains could form lambda1-bearing IgG in Chinese hamster ovary cells, apparent absence of V(H)T/lambda1 anti-pNP IgG may not be due to the incompatibility between the gamma-chains and the lambda1-chain, but may be explained by the fact that V(H)T/lambda1 B cells showed 50- to 100-fold lower affinity for pNP than V(H)T/lambda2 B cells. 4) Interestingly, a pNP-specific IgM mAb that shared common mutations including T313A with high affinity anti-pNP IgG was isolated, suggesting that a part of hypermutation coupled with positive selection can occur before isotype switching. Thus, even weak B cell receptor engagement can elicit an IgM response, whereas only B cells that received signals stronger than a threshold may be committed to an affinity maturation process.
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Affiliation(s)
- Naoki Kanayama
- Department of Biotechnology, Faculty of Engineering, Okayama University, Tsushima-Naka, Okayama, Japan
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62
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Haas KM, Hasegawa M, Steeber DA, Poe JC, Zabel MD, Bock CB, Karp DR, Briles DE, Weis JH, Tedder TF. Complement receptors CD21/35 link innate and protective immunity during Streptococcus pneumoniae infection by regulating IgG3 antibody responses. Immunity 2002; 17:713-23. [PMID: 12479818 DOI: 10.1016/s1074-7613(02)00483-1] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The CD21/35 receptor provides an important link between innate and adaptive immunity. Its importance during protective immune responses to encapsulated extracellular bacteria was assessed using a new line of mice completely deficient in CD21/35 expression (CD21/35(-/-)). CD21/35 expression was essential for the rapid trapping of C3dg-antigen complexes by B cells in vivo, especially in splenic marginal zones. Despite normal B cell development in CD21/35(-/-) mice, T cell-independent and -dependent antibody responses to low-dose antigens were significantly decreased, with a striking impairment in IgG3 responses. Accordingly, CD21/35(-/-) mice were more susceptible to acute lethal Streptococcus pneumoniae infection. Thus, CD21/35 expression is critical for early protective antibody responses to lethal pathogens that rapidly multiply and quickly overwhelm the immune system.
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Affiliation(s)
- Karen M Haas
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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63
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Knoetig SM, Torrey TA, Naghashfar Z, McCarty T, Morse HC. CD19 signaling pathways play a major role for murine AIDS induction and progression. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5607-14. [PMID: 12421939 DOI: 10.4049/jimmunol.169.10.5607] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection of genetically susceptible mice with the LP-BM5 mixture of murine leukemia viruses including an etiologic defective virus (BM5def) causes an immunodeficiency syndrome called murine AIDS (MAIDS). The disease is characterized by interactions between B cells and CD4(+) T cells resulting in polyclonal activation of both cell types. It is known that BM5def is expressed at highest levels in B cells and that B cells serve as viral APC. The CD19-CD21 complex and CD22 on the surface of B cells play critical roles as regulators of B cell responses to a variety of stimuli, influencing cell activation, differentiation, and survival. CD19 integrates positive signals induced by B cell receptor ligation by interacting with the protooncogene Vav, which leads to subsequent tyrosine phosphorylation of this molecule. In contrast, CD22 negatively regulates Vav phosphorylation. To analyze the role of CD19, CD21, Vav, and CD22 in MAIDS, we infected mice deficient in CD19, CD21 (CR2), Vav-1, or CD22 with LP-BM5 murine leukemia viruses. Infected CR2(-/-) mice developed MAIDS with a time course and severity indistinguishable from that of wild-type mice. In contrast, CD19 as well as Vav-1 deficiency restricted viral replication and suppressed the development of typical signs of MAIDS including splenomegaly, lymphadenopathy, and hypergammaglobulinemia. Finally, CD22 deficiency was found to accelerate MAIDS development. These results provide novel insights into the B cell signaling pathways required for normal induction and progression of MAIDS.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antigens, CD19/genetics
- Antigens, CD19/physiology
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antiviral Agents/physiology
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/virology
- Cell Adhesion Molecules
- Cell Cycle Proteins
- Cell Line, Transformed
- Disease Progression
- Immune Sera/biosynthesis
- Immunoglobulin Class Switching/genetics
- Immunoglobulin E/biosynthesis
- Immunophenotyping
- Lectins/deficiency
- Lectins/genetics
- Leukemia Virus, Murine/immunology
- Leukemia Virus, Murine/metabolism
- Lymphocyte Activation/genetics
- Lymphoproliferative Disorders/genetics
- Lymphoproliferative Disorders/immunology
- Lymphoproliferative Disorders/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Murine Acquired Immunodeficiency Syndrome/genetics
- Murine Acquired Immunodeficiency Syndrome/immunology
- Murine Acquired Immunodeficiency Syndrome/pathology
- Murine Acquired Immunodeficiency Syndrome/virology
- Protein Binding/genetics
- Protein Binding/immunology
- Proto-Oncogene Proteins/deficiency
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/physiology
- Proto-Oncogene Proteins c-vav
- Receptors, Complement 3d/deficiency
- Receptors, Complement 3d/genetics
- Severity of Illness Index
- Sialic Acid Binding Ig-like Lectin 2
- Signal Transduction/genetics
- Signal Transduction/immunology
- Spleen/cytology
- Spleen/immunology
- Spleen/metabolism
- Spleen/pathology
- Virus Integration/genetics
- Virus Integration/immunology
- Virus Replication/genetics
- Virus Replication/immunology
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Affiliation(s)
- Sonja M Knoetig
- Laboratory of Immunopathology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 5640 Fishers Lane, Rockville, MD 20852, USA
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64
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Reid RR, Woodcock S, Shimabukuro-Vornhagen A, Austen WG, Kobzik L, Zhang M, Hechtman HB, Moore FD, Carroll MC. Functional activity of natural antibody is altered in Cr2-deficient mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5433-40. [PMID: 12421918 DOI: 10.4049/jimmunol.169.10.5433] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The major source of natural IgM Abs are B-1 cells, which differ from conventional B cells in their anatomic location, cell surface phenotype, restricted usage of particular V(H) genes and limited use of N-region addition during V-D-J rearrangement. The origin of B-1 cells is unclear. However, they are capable of self-renewal and their development is sensitive to signaling via the B cell receptor, as genetic defects that impair the strength of the signal often result in limited development. These findings suggest that B-1 cells require either an intrinsic signal, or contact with Ag, for positive selection and expansion and/or maintenance in the periphery. In support of interaction with cognate Ag, deficiency in the complement receptors CD21/CD35 results in a 30-40% decrease in the CD5(+) B-1 population. To determine whether this reduction reflects a loss of certain specificities or simply a proportional decline in the repertoire, we examined peritoneal B cells isolated from Cr2(+) and Cr2(def) mice for recognition of a B-1 cell Ag, i.e., phosphatidylcholine, and assayed for injury in an IgM natural Ab-dependent model of reperfusion injury. We found a similar frequency of phosphatidylcholine-specific CD5(+) B-1 cells in the two strains of mice. By contrast, the Cr2(def) mice have reduced injury in the IgM-dependent model of reperfusion injury. Reconstitution of the deficient mice with pooled IgM or adoptive transfer of Cr2(+) peritoneal B cells restored injury. These results suggest that complement receptors CD21/CD35 are important in maintenance of the B-1 cell repertoire to some, but not all, specificities.
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Affiliation(s)
- Russell R Reid
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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65
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Marchbank KJ, Kulik L, Gipson MG, Morgan BP, Holers VM. Expression of human complement receptor type 2 (CD21) in mice during early B cell development results in a reduction in mature B cells and hypogammaglobulinemia. THE JOURNAL OF IMMUNOLOGY 2002; 169:3526-35. [PMID: 12244142 DOI: 10.4049/jimmunol.169.7.3526] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Complement receptor (CR) type 2 (CR2/CD21) is normally expressed only during the immature and mature stages of B cell development. In association with CD19, CR2 plays an important role in enhancing mature B cell responses to foreign Ag. We used a murine Vlambda2 promoter/Vlambda2-4 enhancer minigene to develop transgenic mice that initiate expression of human CR2 (hCR2) during the CD43(+)CD25(-) late pro-B cell stage of development. We found peripheral blood B cell numbers reduced by 60% in mice expressing high levels of hCR2 and by 15% in mice with intermediate receptor expression. Splenic B cell populations were altered with an expansion of marginal zone cells, and basal serum IgG levels as well as T-dependent immune responses were also significantly decreased in transgenic mice. Mice expressing the highest levels of hCR2 demonstrated in the bone marrow a slight increase in B220(int)CD43(+)CD25(-) B cells in association with a substantial decrease in immature and mature B cells, indicative of a developmental block in the pro-B cell stage. These data demonstrate that stage-specific expression of CR2 is necessary for normal B cell development, as premature receptor expression substantially alters this process. Alterations in B cell development are most likely due to engagement of pre-B cell receptor-mediated or other regulatory pathways by hCR2 in a CD19- and possibly C3 ligand-dependent manner.
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Affiliation(s)
- Kevin J Marchbank
- Complement Biology Group, Department of Medical Biochemistry, University of Wales College of Medicine, Heath Park, Cardiff, United Kingdom
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66
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Barrington RA, Pozdnyakova O, Zafari MR, Benjamin CD, Carroll MC. B lymphocyte memory: role of stromal cell complement and FcgammaRIIB receptors. J Exp Med 2002; 196:1189-99. [PMID: 12417629 PMCID: PMC2194107 DOI: 10.1084/jem.20021110] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
To dissect the influence of CD21/CD35 and FcgammaRIIB in antigen retention and humoral memory, we used an adoptive transfer model in which antigen-primed B and T lymphocytes were given to sublethally irradiated wild-type mice or mice deficient in CD21/CD35 (Cr2(-/-)) or FcgammaRIIB receptors (FcgammaRIIB(-/-)). Cr2(-/-) chimeras showed impaired memory as characterized by a decrease in antibody titer, reduced frequency of antibody secreting cells, an absence of affinity maturation, and significantly reduced recall response. The impaired memory in Cr2(-/-) chimeras corresponded with the reduced frequency of antigen-specific memory B cells. Interestingly, FcgammaRIIB(-/-) chimeras showed a differential phenotype with impaired splenic but normal bone marrow responses. These data suggest that CD21/CD35 on stroma, including follicular dendritic cells, is critical to the maintenance of long-term B lymphocyte memory.
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Affiliation(s)
- Robert A Barrington
- Center for Blood Research and Department of Pathology, Harvard University, Boston, MA 02115, USA
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67
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Fleming SD, Shea-Donohue T, Guthridge JM, Kulik L, Waldschmidt TJ, Gipson MG, Tsokos GC, Holers VM. Mice deficient in complement receptors 1 and 2 lack a tissue injury-inducing subset of the natural antibody repertoire. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:2126-33. [PMID: 12165541 DOI: 10.4049/jimmunol.169.4.2126] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Intestinal ischemia-reperfusion (IR) injury is initiated when natural Abs recognize neoantigens that are revealed on ischemic cells. Cr2(-/-) mice, deficient in complement receptors (CR)1 and CR2, demonstrate defects in T-dependent B-2 B cell responses to foreign Ags and have also been suggested to manifest abnormalities of the B-1 subset of B lymphocytes. To determine whether these CRs might play a role in the generation of the natural Abs that initiate intestinal IR injury, we performed experiments in Cr2(-/-) and control Cr2(+/+) mice. We found that Cr2(-/-) mice did not demonstrate severe intestinal injury that was readily observed in control Cr2(+/+) mice following IR, despite having identical serum levels of IgM and IgG. Pretreatment of Cr2(-/-) mice before the ischemic phase with IgM and IgG purified from the serum of wild-type C57BL/6 mice reconstituted all key features of IR injury, demonstrating that the defect involves the failure to develop this subset of natural Abs. Pretreatment with IgM and IgG individually demonstrates that each contributes to unique features of IR injury. In sum, CR2/CR1 play an unanticipated but critical role in the development of a subset of the natural Ab repertoire that has particular importance in the pathogenesis of IR injury.
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Affiliation(s)
- Sherry D Fleming
- Department of Cellular Injury, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
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68
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Nielsen CH, Leslie RGQ. Complement’s participation in acquired immunity. J Leukoc Biol 2002. [DOI: 10.1189/jlb.72.2.249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Claus Henrik Nielsen
- Institute for Inflammation Research, Rigshospitalet, University Hospital Copenhagen; and
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69
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Manz RA, Arce S, Cassese G, Hauser AE, Hiepe F, Radbruch A. Humoral immunity and long-lived plasma cells. Curr Opin Immunol 2002; 14:517-21. [PMID: 12088688 DOI: 10.1016/s0952-7915(02)00356-4] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A selected fraction of plasmablasts enters the compartment of nondividing, long-lived plasma cells to maintain humoral antibody memory. In accord with a current model for lymphocyte homeostasis, the lifetime of long-lived plasma cells is probably regulated by competition for a limited number of survival niches present in splenic red pulp, bone marrow and inflamed tissue. Plasma cells secreting autoantibodies specific for some, but not all, self-antigens are probably 'allowed' to enter the compartment of long-lived plasma cells and provide antibody-mediated 'autoimmune memory' that is resistant to conventional therapies.
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Affiliation(s)
- Rudolf A Manz
- Department for Humoral Immunology, German Arthritis Research Centre, Berlin, Schumannstrasse 21/22, Berlin, Germany.
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70
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Mongini PKA, Tolani S, Fattah RJ, Inman JK. Antigen receptor triggered upregulation of CD86 and CD80 in human B cells: augmenting role of the CD21/CD19 co-stimulatory complex and IL-4. Cell Immunol 2002; 216:50-64. [PMID: 12381350 DOI: 10.1016/s0008-8749(02)00512-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The impact of BCR:CD21 co-engagement on B cell expression of molecules critical for T cell activation was investigated with receptor-specific mAbs conjugated to high MW dextran as stimulatory ligands. In the absence of IL-4, BCR:CD21 co-ligation augmented BCR-triggered CD86 only under conditions of very low BCR ligand dose or affinity, and CD80 was minimally induced by BCR and/or CD21 crosslinking. In the presence of IL-4, BCR:CD21 co-ligation augmented CD86 and CD80 expression under conditions of greater BCR engagement. However, with very high level BCR engagement, no bonus effect of BCR:CD21 crosslinking was observed. Co-ligation-promoted CD86 and CD80 expression was associated with heightened B cell activation of resting allogeneic T cells. The data suggest that co-clustering of BCR and the CD21/CD19 co-stimulatory complex following B cell engagement with C3d-bound microbial or self-antigens will enhance B cell recruitment of T cell help only when IL-4 is present and/or BCR engagement is very limiting.
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Affiliation(s)
- Patricia K A Mongini
- Department of Rheumatology, Hospital for Joint Diseases, 301 E. 17th St., New York, NY 10003, USA.
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71
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Toellner KM, Jenkinson WE, Taylor DR, Khan M, Sze DMY, Sansom DM, Vinuesa CG, MacLennan ICM. Low-level hypermutation in T cell-independent germinal centers compared with high mutation rates associated with T cell-dependent germinal centers. J Exp Med 2002; 195:383-9. [PMID: 11828014 PMCID: PMC2193598 DOI: 10.1084/jem.20011112] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Exceptionally germinal center formation can be induced without T cell help by polysaccharide-based antigens, but these germinal centers involute by massive B cell apoptosis at the time centrocyte selection starts. This study investigates whether B cells in germinal centers induced by the T cell-independent antigen (4-hydroxy-3-nitrophenyl)acetyl (NP) conjugated to Ficoll undergo hypermutation in their immunoglobulin V region genes. Positive controls are provided by comparing germinal centers at the same stage of development in carrier-primed mice immunized with a T cell-dependent antigen: NP protein conjugate. False positive results from background germinal centers and false negatives from non-B cells in germinal centers were avoided by transferring B cells with a transgenic B cell receptor into congenic controls not carrying the transgene. By 4 d after immunization, hypermutation was well advanced in the T cell-dependent germinal centers. By contrast, the mutation rate for T cell-independent germinal centers was low, but significantly higher than in NP-specific B cells from nonimmunized transgenic mice. Interestingly, a similar rate of mutation was seen in extrafollicular plasma cells at this stage. It is concluded that efficient activation of hypermutation depends on interaction with T cells, but some hypermutation may be induced without such signals, even outside germinal centers.
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Affiliation(s)
- Kai-Michael Toellner
- Medical Research Council Centre for Immune Regulation, University of Birmingham Medical School, Birmingham B15 2TT, United Kingdom
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72
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Hasegawa M, Fujimoto M, Poe JC, Steeber DA, Tedder TF. CD19 can regulate B lymphocyte signal transduction independent of complement activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:3190-200. [PMID: 11544305 DOI: 10.4049/jimmunol.167.6.3190] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
B lymphocytes are critically regulated by signals transduced through the CD19-CD21 cell surface receptor complex, where complement C3d binding to CD21 supplies an already characterized ligand. To determine the extent that CD19 function is controlled by complement activation, CD19-deficient mice (that are hyporesponsive to transmembrane signals) and mice overexpressing CD19 (that are hyperresponsive) were crossed with CD21- and C3-deficient mice. Cell surface CD19 and CD21 expression were significantly affected by the loss of CD21 and C3 expression, respectively. Mature B cells from CD21-deficient littermates had approximately 36% higher cell surface CD19 expression, whereas CD21/35 expression was increased by approximately 45% on B cells from C3-deficient mice. Negative regulation of CD19 and CD21 expression by CD21 and C3, respectively, may be functionally significant because small increases in cell surface CD19 overexpression can predispose to autoimmunity. Otherwise, B cell development and function in CD19-deficient and -overexpressing mice were not significantly affected by a simultaneous loss of CD21 expression. Although CD21-deficient mice were found to express a hypomorphic cell surface CD21 protein at low levels that associated with mouse CD19, C3 deficiency did not significantly affect B cell development and function in CD19-deficient or -overexpressing mice. These results, and the severe phenotype exhibited by CD19-deficient mice compared with CD21- or C3-deficient mice, collectively demonstrate that CD19 can regulate B cell signaling thresholds independent of CD21 engagement and complement activation.
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Affiliation(s)
- M Hasegawa
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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73
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Schwab J, Illges H. Regulation of CD21 expression by DNA methylation and histone deacetylation. Int Immunol 2001; 13:705-10. [PMID: 11312258 DOI: 10.1093/intimm/13.5.705] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The complement receptor II (CD21) serves as a receptor for the complement component C3d of immune complexes on B lymphocytes. Expression of the CD21 gene is tightly regulated during B lymphocyte differentiation. Only mature B lymphocytes, but not pro-, pre- or plasma B lymphocytes, express CD21. There is evidence that cell type-specific expression is mediated by a silencer element located in the first intron. The CD21 promoter region contains a CpG island adjacent to the ATG start codon. We have analyzed the methylation status of this CpG island in B lymphoid cell lines representing the various differentiation stages of B lymphocyte development and primary lymphocytes. We found that the pro-, pre- and intermediate B lymphocytes contain a methylated CpG island and do not express CD21, whereas CD21-expressing mature B lymphocytes, plasma B lymphocytes and non-lymphoid cells carry a demethylated CD21 CpG island. To analyze whether the lack of CD21 expression in early B lymphocytes is due to inhibition by CpG methylation we have used 5-aza-2'-deoxycytidine to inhibit DNA methyltransferase activity. Treatment of pro-B lymphocytes with the drug resulted in expression of CD21. We have also applied Trichostatin A (TSA), an inhibitor of histone deacetylation, to determine whether the state of histone deacetylation affects the expression of CD21. We found that TSA induces expression of CD21 in early B lymphocytes. Thus CD21 expression is controlled by both methylation of the CD21 CpG island and chromatin modification through histone deacetylation in early B lymphocyte development.
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Affiliation(s)
- J Schwab
- Immunology, Department of Biology, Faculty of Sciences, University of Konstanz, M662, 78457 Konstanz, Germany
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74
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Chen Z, Koralov SB, Kelsoe G. Complement C4 inhibits systemic autoimmunity through a mechanism independent of complement receptors CR1 and CR2. J Exp Med 2000; 192:1339-52. [PMID: 11067882 PMCID: PMC2193358 DOI: 10.1084/jem.192.9.1339] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The complement system enhances antibody responses to T-dependent antigens, but paradoxically, deficiencies in C1 and C4 are strongly linked to autoantibody production in humans. In mice, disruption of the C1qa gene also results in spontaneous autoimmunity. Moreover, deficiencies in C4 or complement receptors 1 and 2 (CR1/CR2) lead to reduced selection against autoreactive B cells and impaired humoral responses. These observations suggest that C1 and C4 act through CR1/CR2 to enhance humoral immunity and somehow suppress autoimmunity. Here we report high titers of spontaneous antinuclear antibody (ANA) in C4(-/)- mice. This systemic lupus erythematosus-like autoimmunity is highly penetrant; by 10 mo of age, all C4(-)(/)- females and most males produced ANA. In contrast, titers and frequencies of ANA in Cr2(-)(/)- mice, which are deficient in CR1 and CR2, never rose significantly above those in normal controls. Glomerular deposition of immune complexes (ICs), glomerulonephritis, and splenomegaly were observed in C4(-)(/)- but not Cr2(-)(/)- mice. C4(-)(/)-, but not Cr2(-)(/)-, mice accumulate activated T and B cells. Clearance of circulating ICs is impaired in preautoimmune C4(-)(/)-, but not Cr2(-)(/)-, mice. C4 deficiency causes spontaneous, lupus-like autoimmunity through a mechanism that is independent of CR1/CR2.
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MESH Headings
- Animals
- Antibodies, Antinuclear/biosynthesis
- Antibodies, Antinuclear/blood
- Antibodies, Antinuclear/immunology
- Antigen-Antibody Complex/immunology
- Autoimmunity/immunology
- Cells, Cultured
- Complement C4/deficiency
- Complement C4/genetics
- Complement C4/immunology
- Complement C4/metabolism
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Deletion
- Histocytochemistry
- Kidney/immunology
- Kidney/pathology
- Lupus Erythematosus, Systemic/complications
- Lupus Erythematosus, Systemic/immunology
- Lupus Erythematosus, Systemic/pathology
- Lymphocyte Activation/immunology
- Male
- Mice
- Mice, Inbred Strains
- Mice, Knockout
- Receptors, Complement 3b/immunology
- Receptors, Complement 3b/metabolism
- Receptors, Complement 3d/deficiency
- Receptors, Complement 3d/genetics
- Receptors, Complement 3d/immunology
- Receptors, Complement 3d/metabolism
- Spleen/immunology
- Spleen/pathology
- Splenomegaly/complications
- Splenomegaly/immunology
- Splenomegaly/pathology
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Affiliation(s)
- Z Chen
- Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA
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75
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Tarlinton DM, Smith KG. Dissecting affinity maturation: a model explaining selection of antibody-forming cells and memory B cells in the germinal centre. IMMUNOLOGY TODAY 2000; 21:436-41. [PMID: 10953095 DOI: 10.1016/s0167-5699(00)01687-x] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Until recently, the relationship between apoptosis, selection in the germinal centre (GC) and production of high-affinity antibody-forming cells (AFCs) and memory B cells has been unclear. Here, Tarlinton and Smith present a model that accounts for the switch in GC production from high-affinity AFCs to memory B cells, and explain how Bcl-2, an inhibitor of apoptosis, can influence memory cells but not bone marrow AFCs.
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Affiliation(s)
- D M Tarlinton
- The Walter and Eliza Hall Institute for Medical Research, PO Royal Melbourne Hospital, Victoria 3050, Australia.
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