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Li Y, Gu R, Yan F, Liu Z, Zhang X, Zhao X, Xu F. Low-dose atorvastatin calcium combined with evolocumab: effect on regulatory proteins, lipid profiles, and cardiac function in coronary heart disease patients. Am J Transl Res 2024; 16:2334-2345. [PMID: 39006254 PMCID: PMC11236639 DOI: 10.62347/zgko3645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/17/2024] [Indexed: 07/16/2024]
Abstract
OBJECTIVE To assess the effects of combining low-dose atorvastatin calcium with evolocumab on complement regulatory protein levels, lipid profiles, and cardiac function in patients with coronary heart disease (CHD). METHODS A prospective randomized controlled study was conducted, with 180 CHD patients enrolled from Guang'anmen Hospital, China Academy of Chinese Medical Sciences, and the Second Hospital of Shanxi Medical University between February 2022 and April 2023. These patients were randomly assigned to either the control group (n = 90), receiving low-dose atorvastatin calcium, or the research group (n = 90), receiving a combination of low-dose atorvastatin calcium and evolocumab. The changes in cardiac function indices, levels of blood lipids and complement proteins, incidence of side effects, and cardiovascular events were compared between the two groups. RESULTS After treatment, both groups exhibited reductions in blood lipid levels. However, the research group demonstrated significantly lower levels of total cholesterol (TC), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) compared to the control group (all P < 0.001). Additionally, improvements in cardiac function indices were observed in both groups, with the research group displaying greater enhancements in cardiac output (CO), stroke volume (SV), and left ventricular ejection fraction (LVEF). Furthermore, the levels of complement regulatory proteins, including CD45, CD46, CD55, and CD59, increased in both groups after treatment, with the research group exhibiting significantly higher levels (all P < 0.001). Notably, the research group also exhibited a lower incidence of cardiovascular events. CONCLUSION The combined use of low-dose atorvastatin calcium and evolocumab effectively modulates complement regulatory protein levels, optimizes blood lipid profiles, and enhances cardiac function in patients with CHD. This combination therapy represents a promising approach for management of CHD.
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Affiliation(s)
- Ying Li
- Department of Cardiology, The First Affiliated Hospital (Yijishan Hospital) of Wannan Medical College Wuhu, China
| | - Rui Gu
- Graduate School of Beijing University of Chinese Medicine, Beijing University of Chinese Medicine Beijing, China
| | - Feng Yan
- Department of Cardiology, Second Hospital of Shanxi Medical University, Shanxi Medical University Taiyuan, Shanxi, China
| | - Zhaoyu Liu
- Graduate School of Beijing University of Chinese Medicine, Beijing University of Chinese Medicine Beijing, China
| | - Xia Zhang
- Department of Neurology, Peking University Aerospace School of Clinical Medicine Beijing, China
| | - Xiaoxia Zhao
- Department of Clinical Laboratory, Tianjin Forth Central Hospital, Nankai University Tianjin, China
| | - Fengquan Xu
- Department of Psychosomatics, Guang'anmen Hospital, China Academy of Chinese Medical Sciences Beijing, China
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2
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Shlomchik MJ, Luo W, Weisel F. Linking signaling and selection in the germinal center. Immunol Rev 2019; 288:49-63. [PMID: 30874353 DOI: 10.1111/imr.12744] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 01/24/2019] [Indexed: 12/24/2022]
Abstract
Germinal centers (GC) are sites of rapid B-cell proliferation in response to certain types of immunization. They arise in about 1 week and can persist for several months. In GCs, B cells differentiate in a unique way and begin to undergo somatic mutation of the Ig V regions at a high rate. GC B cells (GCBC) thus undergo clonal diversification that can affect the affinity of the newly mutant B-cell receptor (BCR) for its driving antigen. Through processes that are still poorly understood, GCBC with higher affinity are selectively expanded while those with mutations that inactivate the BCR are lost. In addition, at various times during the extended GC reaction, some GCBC undergo differentiation into either long-lived memory B cells (MBC) or plasma cells. The cellular and molecular signals that govern these fate decisions are not well-understood, but are an active area of research in multiple laboratories. In this review, we cover both the history of this field and focus on recent work that has helped to elucidate the signals and molecules, such as key transcription factors, that coordinate both positive selection as well as differentiation of GCBC.
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Affiliation(s)
- Mark J Shlomchik
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Wei Luo
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Florian Weisel
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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3
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Prieto JMB, Tallmadge RL, Felippe MJB. Developmental expression of B cell molecules in equine lymphoid tissues. Vet Immunol Immunopathol 2016; 183:60-71. [PMID: 28063478 DOI: 10.1016/j.vetimm.2016.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/23/2016] [Accepted: 12/12/2016] [Indexed: 01/01/2023]
Abstract
Identification and classification of B cell subpopulations has been shown to be challenging and inconsistent among different species. Our study tested aspects of ontogeny, phenotype, tissue distribution, and function of equine CD5hi B cells, which represented a greater proportion of B cells early in development and in the peritoneal cavity. CD5hi and CD5lo B cells differentially expressed B cell markers (CD2, CD21, IgM) measured using flow cytometry, but similar mRNA expression of signature genes (DGKA, FGL2, PAX5, IGHM, IL10) measured using quantitative RT-PCR. Sequencing lambda light chain segments revealed that CD5hi B cells generated diverse immunoglobulin repertoires, and more frequently bound to fluorescence-labeled phosphorylcholine. This study shows developmental characteristics and tissue distribution of a newly described subpopulation of B cells in the horse.
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Affiliation(s)
- J M B Prieto
- Equine Immunology Laboratory, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
| | - R L Tallmadge
- Equine Immunology Laboratory, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
| | - M J B Felippe
- Equine Immunology Laboratory, Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
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4
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Pupovac A, Sluyter R. Roles of extracellular nucleotides and P2 receptors in ectodomain shedding. Cell Mol Life Sci 2016; 73:4159-4173. [PMID: 27180276 PMCID: PMC11108277 DOI: 10.1007/s00018-016-2274-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 05/10/2016] [Indexed: 02/03/2023]
Abstract
Ectodomain shedding of integral membrane receptors results in the release of soluble molecules and modification of the transmembrane portions to mediate or modulate extracellular and intracellular signalling. Ectodomain shedding is stimulated by a variety of mechanisms, including the activation of P2 receptors by extracellular nucleotides. This review describes in detail the roles of extracellular nucleotides and P2 receptors in the shedding of various cell surface molecules, including amyloid precursor protein, CD23, CD62L, and members of the epidermal growth factor, immunoglobulin and tumour necrosis factor families. This review discusses the mechanisms involved in P2 receptor-mediated shedding, demonstrating central roles for the P2 receptors, P2X7 and P2Y2, and the sheddases, ADAM10 and ADAM17, in this process in a number of cell types.
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Affiliation(s)
- Aleta Pupovac
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Ronald Sluyter
- School of Biological Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Centre for Medical and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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5
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Snapper CM. Differential regulation of polysaccharide-specific antibody responses to isolated polysaccharides, conjugate vaccines, and intact Gram-positive versus Gram-negative extracellular bacteria. Vaccine 2016; 34:3542-8. [DOI: 10.1016/j.vaccine.2015.12.077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/08/2015] [Accepted: 12/14/2015] [Indexed: 01/11/2023]
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6
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Abstract
PURPOSE OF REVIEW Thirty years ago, investigators isolated and later determined the structure of HIV-1 and its envelope proteins. Using techniques that were effective with other viruses, they prepared vaccines designed to generate antibody or T-cell responses, but they were ineffective in clinical trials. In this article, we consider the role of complement in host defense against enveloped viruses, the role it might play in the antibody response and why complement has not controlled HIV-1 infection. RECENT FINDINGS Complement consists of a large group of cell-bound and plasma proteins that are an integral part of the innate immune system. They provide a first line of defense against microbes and also play a role in the immune response. Here we review the studies of complement-mediated HIV destruction and the role of complement in the HIV antibody response. SUMMARY HIV-1 has evolved a complex defense to prevent complement-mediated killing reviewed here. As part of these studies, we have discovered that HIV-1 envelope, on administration into animals, is rapidly broken down into small peptides that may prove to be very inefficient at provident the type of antigenic stimulation that leads to an effective immune response. Improving complement binding and stabilizing envelope may improve the vaccine response.
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7
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Complement Attack against Aspergillus and Corresponding Evasion Mechanisms. Interdiscip Perspect Infect Dis 2012; 2012:463794. [PMID: 22927844 PMCID: PMC3423931 DOI: 10.1155/2012/463794] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 06/08/2012] [Accepted: 06/08/2012] [Indexed: 11/26/2022] Open
Abstract
Invasive aspergillosis shows a high mortality rate particularly in immunocompromised patients. Perpetually increasing numbers of affected patients highlight the importance of a clearer understanding of interactions between innate immunity and fungi. Innate immunity is considered to be the most significant host defence against invasive fungal infections. Complement represents a crucial part of this first line defence and comprises direct effects against invading pathogens as well as bridging functions to other parts of the immune network. However, despite the potency of complement to attack foreign pathogens, the prevalence of invasive fungal infections is increasing. Two possible reasons may explain that phenomenon: First, complement activation might be insufficient for an effective antifungal defence in risk patients (due to, e.g., low complement levels, poor recognition of fungal surface, or missing interplay with other immune elements in immunocompromised patients). On the other hand, fungi may have developed evasion strategies to avoid recognition and/or eradication by complement.
In this review, we summarize the most important interactions between Aspergillus and the complement system. We describe the various ways of complement activation by Aspergillus and the antifungal effects of the system, and also show proven and probable mechanisms of Aspergillus for complement evasion.
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8
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Snapper CM. Mechanisms underlying in vivo polysaccharide-specific immunoglobulin responses to intact extracellular bacteria. Ann N Y Acad Sci 2012; 1253:92-101. [DOI: 10.1111/j.1749-6632.2011.06329.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Frank MM. CD21 deficiency, complement, and the development of common variable immunodeficiency. J Allergy Clin Immunol 2012; 129:811-3. [PMID: 22277200 DOI: 10.1016/j.jaci.2011.12.982] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 12/02/2011] [Indexed: 11/18/2022]
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10
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Arjunaraja S, Massari P, Wetzler LM, Lees A, Colino J, Snapper CM. The nature of an in vivo anti-capsular polysaccharide response is markedly influenced by the composition and/or architecture of the bacterial subcapsular domain. THE JOURNAL OF IMMUNOLOGY 2011; 188:569-77. [PMID: 22156342 DOI: 10.4049/jimmunol.1101446] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In vivo anti-polysaccharide Ig responses to isolated polysaccharide (PS) are T cell independent, rapid, and fail to generate memory. However, little is known regarding PS-specific Ig responses to intact gram-positive and gram-negative extracellular bacteria. We previously demonstrated that intact heat-killed Streptococcus pneumoniae, a gram-positive bacterium, elicited a rapid primary pneumococcal capsular PS (PPS) response in mice that was dependent on CD4(+) T cells, B7-dependent costimulation, and CD40-CD40L interactions. However, this response was ICOS independent and failed to generate a boosted PPS-specific secondary IgG response. In the current study, we analyzed the murine meningococcal type C PS (MCPS)-specific Ig response to i.p.-injected intact, heat-killed Neisseria meningitidis, serogroup C (MenC), a gram-negative bacterium. In contrast to S. pneumoniae, the IgG anti-MCPS response to MenC exhibited delayed primary kinetics and was highly boosted after secondary immunization, whereas the IgG anti-MCPS response to isolated MCPS was rapid, without secondary boosting, and consisted of only IgG1 and IgG3, as opposed to all four IgG isotypes in response to intact MenC. The secondary, but not primary, IgG anti-MCPS response to MenC was dependent on CD4(+) T cells, CD40L, CD28, and ICOS. The primary and secondary IgG anti-MCPS responses were lower in TLR4-defective (C3H/HeJ) but not TLR2(-/-) or MyD88(-/-) mice, but secondary boosting was still observed. Of interest, coimmunization of S. pneumoniae and MenC resulted in a boosted secondary IgG anti-PPS response to S. pneumoniae. Our data demonstrate that the nature of the in vivo anti-PS response is markedly influenced by the composition and/or architecture of the bacterial subcapsular domain.
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Affiliation(s)
- Swadhinya Arjunaraja
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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11
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Stromal cell independent B cell development in vitro: generation and recovery of autoreactive clones. J Immunol Methods 2010; 354:53-67. [PMID: 20109461 DOI: 10.1016/j.jim.2010.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 01/15/2010] [Accepted: 01/19/2010] [Indexed: 11/24/2022]
Abstract
We describe and characterize a stromal cell independent culture system that efficiently supports pro-B cell to IgM+ B cell development with near normal levels of IgH and Igkappa diversity. Pro-B cells present in non-adherent bone marrow cells proliferate in the presence of IL-7 and subsequent to the removal of IL-7 and addition of BAFF, differentiate normally into IgM+ B cells. B cell development in vitro closely follows the patterns of development in vivo with culture-derived (CD) B cells demonstrating characteristic patterns of surface antigen expression and gene activation. IgM+ CD B cells respond to TLR stimulation by proliferation and differentiation into antibody-secreting cells. Self-reactive IgM+ B cell development is blocked in 3H9 IgH knockin mice; however, cultures of 3H9 IgH knockin pro-B cells yields high frequencies of "forbidden", autoreactive IgM+ B cells. Furthermore, serum IgG autoantibody exceeded that present in autoimmune, C4(-/-) animals following the reconstitution of RAG1(-/-) mice with IgM+ CD cells derived from BL/6 mice.
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12
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Abstract
Fungal infections are a serious complication in immunocompromised patients such as human immunodeficiency virus-infected individuals, patients with organ transplantations or with haematological neoplasia. The lethality of opportunistic fungal infection is high despite a growing arsenal of antimycotic drugs, implying the urgent need for supportive immunological therapies to strengthen the current inefficient antimicrobial defences of the immunocompromised host. Therefore, increasing effort has been directed to investigating the interplay between fungi and the host immunity and thus to find starting points for additional therapeutic approaches. In this article, we review the actual state of the art concerning the role of complement in the pathogenesis of fungal infections. Important aspects include the activation of the complement system by the fungal pathogen, the efficiency of the complement-associated antimicrobial functions and the arsenal of immune evasion strategies applied by the fungi. The twin functions of complement as an interactive player of the innate immunity and at the same time as a modulator of the adaptive immunity make this defence weapon a particularly interesting therapeutic candidate to mobilise a more effective immune response and to strengthen in one fell swoop a broad spectrum of different immune reactions. However, we also mention the 'Yin-Yang' nature of the complement system in fungal infections, as growing evidence assigns to complement a contributory part in the pathogenesis of fungus-induced allergic manifestations.
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Affiliation(s)
- Cornelia Speth
- Department of Hygiene, Microbiology and Social Medicine, Division of Hygiene and Medical Microbiology, Innsbruck Medical University, Innsbruck, Austria.
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13
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Complement is an essential component of the immune response to adeno-associated virus vectors. J Virol 2008; 82:2727-40. [PMID: 18199646 DOI: 10.1128/jvi.01990-07] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Adeno-associated virus (AAV) vectors are associated with relatively mild host immune responses in vivo. Although AAV induces very weak innate immune responses, neutralizing antibodies against the vector capsid and transgene still occur. To understand further the basis of the antiviral immune response to AAV vectors, studies were performed to characterize AAV interactions with macrophages. Primary mouse macrophages and human THP-1 cells transduced in vitro using an AAV serotype 2 (AAV2) vector encoding green fluorescent protein did not result in measurable transgene expression. An assessment of internalized vector genomes showed that AAV2 vector uptake was enhanced in the presence of normal but not heat-inactivated or C3-depleted mouse/human serum. Enhanced uptake in the presence of serum coincided with increased macrophage activation as determined by the expression of NF-kappaB-dependent genes such as macrophage inflammatory protein 2 (MIP-2), interleukin-1beta (IL-1beta), IL-8, and MIP-1beta. AAV vector serotypes 1 and 8 also activated human and mouse macrophages in a serum-dependent manner. Immunoprecipitation studies demonstrated the binding of iC3b complement protein to the AAV2 capsid in human serum. AAV2 did not activate the alternative pathway of the complement cascade and lacked cofactor activity for factor I-mediated degradation of C3b to iC3b. Instead, our results suggest that the AAV capsid also binds complement regulatory protein factor H. In vivo, complement receptor 1/2- and C3-deficient mice displayed impaired humoral immunity against AAV2 vectors, with a delay in antibody development and significantly lower neutralizing antibody titers. These results show that the complement system is an essential component of the host immune response to AAV.
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14
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Di Carlo E, Magnasco S, D'Antuono T, Tenaglia R, Sorrentino C. The prostate-associated lymphoid tissue (PALT) is linked to the expression of homing chemokines CXCL13 and CCL21. Prostate 2007; 67:1070-80. [PMID: 17474076 DOI: 10.1002/pros.20604] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The genitourinary tract is regarded as part of the mucosal immune system. However, the structural and functional aspects of the human prostate-associated lymphoid tissue (PALT) have never been extensively explored. METHODS This article describes our investigation of this issue by means of immunohistological, confocal, and ultrastructural examination of the normal human prostate. RESULTS PALT consists of two main components: (1) intraepithelial leukocytes, namely CD3(+)T cells with prevalent CD8(+) and CD45RA(-)CD45RO(+) phenotype, sometimes CD69(+), followed by CD94(+)NK, CD11c(+)DCs, some expressing CD86, DC-SIGN(+)DCs and a few B lymphocytes; (2) lymphoid aggregates, frequently below the epithelia, arranged in B cell follicles, endowed with a central ICAM-1(+)VCAM-1(+)CD21(+)FDCs network expressing BLC/CXCL13, and parafollicular T cell areas crossed by PNAd(+)HEV-like vessels showing SLC/CCL21 expression. Parafollicular areas were formed of prevalent CD4(+)T lymphocytes, both CD45RA(-) and CD45RO(+), and intermingled with CD11c(+)DCs. Germinal-center-containing follicles are few and their parafollicular areas are scantily infiltrated by Foxp3(+)CD69(-) highly suppressive regulatory T cells. Most lymphoid follicles lack a distinct germinal center and their parafollicular area harbor numerous Foxp3(+)CD69(-) cells. CONCLUSIONS Comparison with the tonsils shows that PALT displays immunomorphological features required for the onset of cellular and humoral immune responses, while its T regulatory cells appear to function as suppressor-regulators of T and B cell responses.
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Affiliation(s)
- Emma Di Carlo
- Department of Oncology and Neurosciences, G. d'Annunzio University, Chieti, Italy.
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15
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Aydar Y, Sukumar S, Szakal AK, Tew JG. The influence of immune complex-bearing follicular dendritic cells on the IgM response, Ig class switching, and production of high affinity IgG. THE JOURNAL OF IMMUNOLOGY 2005; 174:5358-66. [PMID: 15843533 DOI: 10.4049/jimmunol.174.9.5358] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It is believed that Ag in immune complexes (ICs) on follicular dendritic cells (FDCs) selects high affinity B cells and promotes affinity maturation. However, selection has been documented in the absence of readily detectable ICs on FDCs, suggesting that FDC-ICs may not be important. These results prompted experiments to test the hypothesis that IC-bearing murine FDCs can promote high affinity IgG responses by selecting B cells after stimulating naive IgM(+) cells to mature and class switch. Coculturing naive lambda(+) B cells, FDCs, (4-hydroxy-3-nitrophenyl)acetyl-chicken gamma-globulin (CGG) + anti-CGG ICs, and CGG-primed T cells resulted in FDC-lymphocyte clusters and production of anti-4-hydroxy-5-iodo-3-nitrophenyl acetyl. Class switching was indicated by a shift from IgM to IgG, and affinity maturation was indicated by a change from mostly low affinity IgM and IgG in the first week to virtually all high affinity IgG anti-4-hydroxy-5-iodo-3-nitrophenyl acetyl in the second week. Class switching and affinity maturation were easily detectable in the presence of FDCs bearing appropriate ICs, but not in the absence of FDCs. Free Ag plus FDCs resulted in low affinity IgG, but affinity maturation was only apparent when FDCs bore ICs. Class switching is activation-induced cytidine deaminase (AID) dependent, and blocking FDC-CD21 ligand-B cell CD21 interactions inhibited FDC-IC-mediated enhancement of AID production and the IgG response. In short, these data support the concept that ICs on FDCs can promote AID production, class switching, and maturation of naive IgM(+) B cells, and further suggest that the IC-bearing FDCs help select high affinity B cells that produce high affinity IgG.
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Affiliation(s)
- Yüksel Aydar
- Department of Microbiology, Virginia Commonwealth University, Richmond, VA 23298, USA
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16
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Gatto D, Pfister T, Jegerlehner A, Martin SW, Kopf M, Bachmann MF. Complement receptors regulate differentiation of bone marrow plasma cell precursors expressing transcription factors Blimp-1 and XBP-1. ACTA ACUST UNITED AC 2005; 201:993-1005. [PMID: 15767369 PMCID: PMC2213108 DOI: 10.1084/jem.20042239] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Humoral immune responses are thought to be enhanced by complement-mediated recruitment of the CD21-CD19-CD81 coreceptor complex into the B cell antigen receptor (BCR) complex, which lowers the threshold of B cell activation and increases the survival and proliferative capacity of responding B cells. To investigate the role of the CD21-CD35 complement receptors in the generation of B cell memory, we analyzed the response against viral particles derived from the bacteriophage Qbeta in mice deficient in CD21-CD35 (Cr2(-/-)). Despite highly efficient induction of early antibody responses and germinal center (GC) reactions to immunization with Qbeta, Cr2(-/-) mice exhibited impaired antibody persistence paralleled by a strongly reduced development of bone marrow plasma cells. Surprisingly, antigen-specific memory B cells were essentially normal in these mice. In the absence of CD21-mediated costimulation, Qbeta-specific post-GC B cells failed to induce the transcriptional regulators Blimp-1 and XBP-1 driving plasma cell differentiation, and the antiapoptotic protein Bcl-2, which resulted in failure to generate the precursor population of long-lived plasma cells residing in the bone marrow. These results suggest that complement receptors maintain antibody responses by delivery of differentiation and survival signals to precursors of bone marrow plasma cells.
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MESH Headings
- Allolevivirus/immunology
- Animals
- Antibodies, Viral/immunology
- Antibody Formation/genetics
- Antibody Formation/immunology
- Antigens, CD
- Antigens, Viral/immunology
- Apoptosis/genetics
- Apoptosis/immunology
- Bone Marrow Cells/cytology
- Bone Marrow Cells/immunology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Survival/genetics
- Cell Survival/immunology
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/immunology
- Gene Expression Regulation/genetics
- Gene Expression Regulation/immunology
- Mice
- Mice, Knockout
- Nuclear Proteins/biosynthesis
- Nuclear Proteins/immunology
- Plasma Cells/immunology
- Positive Regulatory Domain I-Binding Factor 1
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-bcl-2/immunology
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Complement 3d/genetics
- Receptors, Complement 3d/immunology
- Regulatory Factor X Transcription Factors
- Repressor Proteins/biosynthesis
- Repressor Proteins/immunology
- Signal Transduction/genetics
- Signal Transduction/immunology
- Transcription Factors/biosynthesis
- Transcription Factors/immunology
- X-Box Binding Protein 1
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Affiliation(s)
- Dominique Gatto
- Cytos Biotechnology, Swiss Federal Institute of Technology, Zurich-Schlieren 8952, Switzerland
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Fleming SD, Egan RP, Chai C, Girardi G, Holers VM, Salmon J, Monestier M, Tsokos GC. Anti-phospholipid antibodies restore mesenteric ischemia/reperfusion-induced injury in complement receptor 2/complement receptor 1-deficient mice. THE JOURNAL OF IMMUNOLOGY 2005; 173:7055-61. [PMID: 15557203 DOI: 10.4049/jimmunol.173.11.7055] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Complement receptor 2-deficient (Cr2(-/-)) mice are resistant to mesenteric ischemia/reperfusion (I/R) injury because they lack a component of the natural Ab repertoire. Neither the nature of the Abs that are involved in I/R injury nor the composition of the target Ag, to which recognition is lacking in Cr2(-/-) mice, is known. Because anti-phospholipid Abs have been shown to mediate fetal growth retardation and loss when injected into pregnant mice, we performed experiments to determine whether anti-phospholipid Abs can also reconstitute I/R injury and, therefore, represent members of the injury-inducing repertoire that is missing in Cr2(-/-) mice. We demonstrate that both murine and human monoclonal and polyclonal Abs against negatively charged phospholipids can reconstitute mesenteric I/R-induced intestinal and lung tissue damage in Cr2(-/-) mice. In addition, Abs against beta2 glycoprotein I restore local and remote tissue damage in the Cr2(-/-) mice. Unlike Cr2(-/-) mice, reconstitution of I/R tissue damage in the injury-resistant Rag-1(-/-) mouse required the infusion of both anti-beta2-glycoprotein I and anti-phospholipid Ab. We conclude that anti-phospholipid Abs can bind to tissues subjected to I/R insult and mediate tissue damage.
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MESH Headings
- Animals
- Antibodies, Anticardiolipin/administration & dosage
- Antibodies, Anticardiolipin/therapeutic use
- Antibodies, Antiphospholipid/administration & dosage
- Antibodies, Antiphospholipid/metabolism
- Antibodies, Antiphospholipid/therapeutic use
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/metabolism
- Antibodies, Monoclonal/therapeutic use
- Female
- Glycoproteins/immunology
- Glycoproteins/metabolism
- Homeodomain Proteins/genetics
- Humans
- Immune Sera/administration & dosage
- Infusions, Intravenous
- Intestinal Mucosa/blood supply
- Intestinal Mucosa/immunology
- Intestinal Mucosa/pathology
- Lung/immunology
- Lung/pathology
- Male
- Mesenteric Arteries
- Mice
- Mice, Knockout
- Receptors, Complement 3b/deficiency
- Receptors, Complement 3b/genetics
- Receptors, Complement 3b/physiology
- Receptors, Complement 3d/deficiency
- Receptors, Complement 3d/genetics
- Receptors, Complement 3d/physiology
- Reperfusion Injury/genetics
- Reperfusion Injury/immunology
- Reperfusion Injury/prevention & control
- beta 2-Glycoprotein I
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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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18
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Bouts AHM, Krediet RT, Davin JC, Monnens LAH, Nauta J, Schröder CH, van de Winkel JGJ, Out TA. IGG and complement receptor expression on peripheral white blood cells in uraemic children. Nephrol Dial Transplant 2004; 19:2296-301. [PMID: 15266033 DOI: 10.1093/ndt/gfh402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Phagocytosis of IgG- or complement-opsonized bacteria and antibody production by lymphocytes are regulated by cell surface receptors for IgG (FcgammaRI, FcgammaRII and FcgammaRIII) and complement (CR1 and CR3). We measured the effect of uraemia and dialysis treatment on FcgammaR and CR expression on leukocytes in blood. METHODS Blood samples were obtained from children: 40 treated with peritoneal dialysis (PD), 23 with haemodialysis (HD), 46 not yet dialysed (CRF) and 33 healthy (HC). White blood cells, isolated from EDTA-blood by centrifugation after cell fixation with paraformaldehyde, were labelled with FITC-conjugated CD16 (FcgammaRIII), CD32 (FcgammaRII), CD64 (FcgammaRI), CD11b (CR3) and CD35 (CR1) monoclonal antibodies and analysed by flow cytometry. RESULTS In PD, HD, CRF and HC, monocytes and neutrophils were all positive for FcgammaR and CR, except for CD16 on monocytes (20% positive). Lymphocytes expressed CD16 and CD32 but not CD64. PD, HD and CRF children had lower percentages of CD16(+) and CD32(+) lymphocytes compared with HC. The percentage of CD11b(+) lymphocytes was lower only in PD and the percentage of CD35(+) lymphocytes was lower in HD and CRF compared with HC. The median CD32 mean fluorescense intensity (MFI) on lymphocytes, monocytes and neutrophils was lower in PD, HD and CRF compared with HC. On the other hand, CD11b MFI on lymphocytes, monocytes and neutrophils was higher in PD, HD and CRF children compared with HC. CD16 and CD64 MFI were not different among the groups and CD35 MFI was only lower on lymphocytes from PD, HD and CRF compared with HC. CONCLUSIONS In children with chronic renal failure, whether dialysed or not, FcgammaRII expression on lymphocytes, monocytes and neutrophils was reduced and CR3 expression was increased. Furthermore, CR1 expression on lymphocytes, important for the humoral response, was lower in children with renal failure. Age and uraemia are associated with these abnormalities and might contribute to impaired immune function in children with chronic renal failure.
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Affiliation(s)
- Antonia H M Bouts
- Emma Children's Hospital, G8-218, Academic Medical Center, PO Box 22700, 1100 DE, Amsterdam, the Netherlands.
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19
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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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20
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Lindorfer MA, Jinivizian HB, Foley PL, Kennedy AD, Solga MD, Taylor RP. B cell complement receptor 2 transfer reaction. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:3671-8. [PMID: 12646632 DOI: 10.4049/jimmunol.170.7.3671] [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: 11/19/2022]
Abstract
The B cell C receptor specific for C3dg (CR2) shares a number of features with the primate E C receptor (CR1). Previously, we have demonstrated, both in vitro and in animal models, that immune complexes (IC) bound to primate E CR1, either via C opsonization or by means of bispecific mAb complexes, can be transferred to acceptor macrophages in a process that also removes CR1 from the E. We have now extended this paradigm, the transfer reaction, to include B cell CR2. We used both flow cytometry and fluorescence microscopy to demonstrate that IC bound to Raji cell CR2, either via C opsonization or through the use of an anti-CR2 mAb, are transferred to acceptor THP-1 cells. This reaction, which appears to require Fc recognition of IgG bound to Raji cell CR2, also leads to transfer of CR2. Additional support for the B cell transfer reaction is provided in a prototype study in a monkey model in which IC bound to B cell CR2 are localized to the spleen. These findings may have important implications with respect to defining the role of C in IC handling during the normal immune response.
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Affiliation(s)
- Margaret A Lindorfer
- Department of Biochemistry and Molecular Genetics, University of Virginia Health Sciences Center, Charlottesville, VA 22908-0733, USA
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21
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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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22
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Abstract
The humoral immune response arises from a complex choreography of cells and molecules that interact to produce lasting and effective defenses against pathogens. For more than fifteen years, our laboratory has studied how humoral responses are initiated, how they mature, and how they are remembered. This work has come from many hands and in this brief synopsis, I cannot provide the full recognition that my students, postdoctoral fellows, and collaborators merit. I hope that my colleagues can accept this translucence and know that their efforts are recognized and deeply appreciated, nonetheless.
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Affiliation(s)
- G Kelsoe
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA.
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