1
|
Aboul-Ella H, Gohar A, Ali AA, Ismail LM, Mahmoud AEER, Elkhatib WF, Aboul-Ella H. Monoclonal antibodies: From magic bullet to precision weapon. MOLECULAR BIOMEDICINE 2024; 5:47. [PMID: 39390211 PMCID: PMC11467159 DOI: 10.1186/s43556-024-00210-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Accepted: 09/19/2024] [Indexed: 10/12/2024] Open
Abstract
Monoclonal antibodies (mAbs) are used to prevent, detect, and treat a broad spectrum of non-communicable and communicable diseases. Over the past few years, the market for mAbs has grown exponentially with an expected compound annual growth rate (CAGR) of 11.07% from 2024 (237.64 billion USD estimated at the end of 2023) to 2033 (679.03 billion USD expected by the end of 2033). Ever since the advent of hybridoma technology introduced in 1975, antibody-based therapeutics were realized using murine antibodies which further progressed into humanized and fully human antibodies, reducing the risk of immunogenicity. Some benefits of using mAbs over conventional drugs include a drastic reduction in the chances of adverse reactions, interactions between drugs, and targeting specific proteins. While antibodies are very efficient, their higher production costs impede the process of commercialization. However, their cost factor has been improved by developing biosimilar antibodies as affordable versions of therapeutic antibodies. Along with the recent advancements and innovations in antibody engineering have helped and will furtherly help to design bio-better antibodies with improved efficacy than the conventional ones. These novel mAb-based therapeutics are set to revolutionize existing drug therapies targeting a wide spectrum of diseases, thereby meeting several unmet medical needs. This review provides comprehensive insights into the current fundamental landscape of mAbs development and applications and the key factors influencing the future projections, advancement, and incorporation of such promising immunotherapeutic candidates as a confrontation approach against a wide list of diseases, with a rationalistic mentioning of any limitations facing this field.
Collapse
Affiliation(s)
- Hassan Aboul-Ella
- Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt.
| | - Asmaa Gohar
- Department of Microbiology and Immunology, Faculty of Pharmacy, Galala University, Suez, Egypt
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University (ACU), Giza, Egypt
- Egyptian Drug Authority (EDA), Giza, Egypt
| | - Aya Ahmed Ali
- Department of Microbiology and Immunology, Faculty of Pharmacy, Sinai University, Sinai, Egypt
| | - Lina M Ismail
- Department of Biotechnology and Molecular Chemistry, Faculty of Science, Cairo University, Giza, Egypt
- Creative Egyptian Biotechnologists (CEB), Giza, Egypt
| | | | - Walid F Elkhatib
- Department of Microbiology and Immunology, Faculty of Pharmacy, Galala University, Suez, Egypt
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Heba Aboul-Ella
- Department of Pharmacognosy, Faculty of Pharmacy and Drug Technology, Egyptian Chinese University (ECU), Cairo, Egypt
- Scientific Research Group in Egypt (SRGE), Cairo, Egypt
| |
Collapse
|
2
|
Chen X, Gula H, Pius T, Ou C, Gomozkova M, Wang LX, Schneewind O, Missiakas D. Immunoglobulin G subclasses confer protection against Staphylococcus aureus bloodstream dissemination through distinct mechanisms in mouse models. Proc Natl Acad Sci U S A 2023; 120:e2220765120. [PMID: 36972444 PMCID: PMC10083571 DOI: 10.1073/pnas.2220765120] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/03/2023] [Indexed: 03/29/2023] Open
Abstract
Antibodies bind target molecules with exquisite specificity. The removal of these targets is mediated by the effector functions of antibodies. We reported earlier that the monoclonal antibody (mAb) 3F6 promotes opsonophagocytic killing of Staphylococcus aureus in blood and reduces bacterial replication in animals. Here, we generated mouse immunoglobulin G (mIgG) subclass variants and observed a hierarchy in protective efficacy 3F6-mIgG2a > 3F6-mIgG1 ≥ 3F6-mIgG2b >> 3F6-mIgG3 following bloodstream challenge of C57BL/6J mice. This hierarchy was not observed in BALB/cJ mice: All IgG subclasses conferred similar protection. IgG subclasses differ in their ability to activate complement and interact with Fcγ receptors (FcγR) on immune cells. 3F6-mIgG2a-dependent protection was lost in FcγR-deficient, but not in complement-deficient C57BL/6J animals. Measurements of the relative ratio of FcγRIV over complement receptor 3 (CR3) on neutrophils suggest the preferential expression of FcγRIV in C57BL/6 mice and of CR3 in BALB/cJ mice. To determine the physiological significance of these differing ratios, blocking antibodies against FcγRIV or CR3 were administered to animals before challenge. Correlating with the relative abundance of each receptor, 3F6-mIgG2a-dependent protection in C57BL/6J mice showed a greater reliance for FcγRIV while protection in BALB/cJ mice was only impaired upon neutralization of CR3. Thus, 3F6-based clearance of S. aureus in mice relies on a strain-specific contribution of variable FcγR- and complement-dependent pathways. We surmise that these variabilities are the result of genetic polymorphism(s) that may be encountered in other mammals including humans and may have clinical implications in predicting the efficacy of mAb-based therapies.
Collapse
Affiliation(s)
- Xinhai Chen
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, IL60439
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen518132, China
| | - Haley Gula
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, IL60439
| | - Tonu Pius
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, IL60439
| | - Chong Ou
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD20742
| | - Margaryta Gomozkova
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD20742
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD20742
| | - Olaf Schneewind
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, IL60439
| | - Dominique Missiakas
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, IL60439
| |
Collapse
|
3
|
Bryan AM, You JK, Li G, Kim J, Singh A, Morstein J, Trauner D, Pereira de Sá N, Normile TG, Farnoud AM, London E, Del Poeta M. Cholesterol and sphingomyelin are critical for Fcγ receptor-mediated phagocytosis of Cryptococcus neoformans by macrophages. J Biol Chem 2021; 297:101411. [PMID: 34793834 PMCID: PMC8661020 DOI: 10.1016/j.jbc.2021.101411] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 11/04/2021] [Accepted: 11/11/2021] [Indexed: 12/21/2022] Open
Abstract
Cryptococcus neoformans is a fungal pathogen that causes life-threatening meningoencephalitis in lymphopenic patients. Pulmonary macrophages comprise the first line of host defense upon inhalation of fungal spores by aiding in clearance but can also potentially serve as a niche for their dissemination. Given that macrophages play a key role in the outcome of a cryptococcal infection, it is crucial to understand factors that mediate phagocytosis of C. neoformans. Since lipid rafts (high-order plasma membrane domains enriched in cholesterol and sphingomyelin [SM]) have been implicated in facilitating phagocytosis, we evaluated whether these ordered domains govern macrophages' ability to phagocytose C. neoformans. We found that cholesterol or SM depletion resulted in significantly deficient immunoglobulin G (IgG)-mediated phagocytosis of fungus. Moreover, repletion of macrophage cells with a raft-promoting sterol (7-dehydrocholesterol) rescued this phagocytic deficiency, whereas a raft-inhibiting sterol (coprostanol) significantly decreased IgG-mediated phagocytosis of C. neoformans. Using a photoswitchable SM (AzoSM), we observed that the raft-promoting conformation (trans-AzoSM) resulted in efficient phagocytosis, whereas the raft-inhibiting conformation (cis-AzoSM) significantly but reversibly blunted phagocytosis. We observed that the effect on phagocytosis may be facilitated by Fcγ receptor (FcγR) function, whereby IgG immune complexes crosslink to FcγRIII, resulting in tyrosine phosphorylation of FcR γ-subunit (FcRγ), an important accessory protein in the FcγR signaling cascade. Correspondingly, cholesterol or SM depletion resulted in decreased FcRγ phosphorylation. Repletion with 7-dehydrocholesterol restored phosphorylation, whereas repletion with coprostanol showed FcRγ phosphorylation comparable to unstimulated cells. Together, these data suggest that lipid rafts are critical for facilitating FcγRIII-mediated phagocytosis of C. neoformans.
Collapse
Affiliation(s)
- Arielle M Bryan
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Jeehyun Karen You
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Guangtao Li
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - JiHyun Kim
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Ashutosh Singh
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Johannes Morstein
- Department of Chemistry, New York University, New York, New York, USA
| | - Dirk Trauner
- Department of Chemistry, New York University, New York, New York, USA
| | - Nívea Pereira de Sá
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Tyler G Normile
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Amir M Farnoud
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA
| | - Erwin London
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, USA; Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, USA; Veteran Affairs Medical Center, Northport, New York, USA.
| |
Collapse
|
4
|
Rezende CP, Brito PKMO, Da Silva TA, Pessoni AM, Ramalho LNZ, Almeida F. Influence of Galectin-3 on the Innate Immune Response during Experimental Cryptococcosis. J Fungi (Basel) 2021; 7:jof7060492. [PMID: 34203011 PMCID: PMC8234158 DOI: 10.3390/jof7060492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 11/16/2022] Open
Abstract
Cryptococcus neoformans, the causative agent of cryptococcosis, is the primary fungal pathogen that affects the immunocompromised individuals. Galectin-3 (Gal-3) is an animal lectin involved in both innate and adaptive immune responses. The present study aimed to evaluate the influence of Gal-3 on the C. neoformans infection. We performed histopathological and gene profile analysis of the innate antifungal immunity markers in the lungs, spleen, and brain of the wild-type (WT) and Gal-3 knockout (KO) mice during cryptococcosis. These findings suggest that Gal-3 absence does not cause significant histopathological alterations in the analyzed tissues. The expression profile of the genes related to innate antifungal immunity showed that the presence of cryptococcosis in the WT and Gal-3 KO animals, compared to their respective controls, promoted the upregulation of the pattern recognition receptor (PRR) responsive to mannose/chitin (mrc1) and a gene involved in inflammation (ccr5), as well as the downregulation of the genes related to signal transduction (card9, fos, ikbkb, jun) and PRRs (cd209a, colec12, nptx1). The absence of Gal-3, in fungal infection, a positively modulated gene involved in phagocytosis (sftpd) and negatively genes involved in signal transduction (syk and myd88), proinflammatory cytokines il-1β and il-12b and cd209a receptor. Therefore, our results suggest that Gal-3 may play an essential role in the development of antifungal immune responses against cryptococcosis.
Collapse
Affiliation(s)
- Caroline Patini Rezende
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (C.P.R.); (A.M.P.)
| | - Patricia Kellen Martins Oliveira Brito
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (P.K.M.O.B.); (T.A.D.S.)
| | - Thiago Aparecido Da Silva
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (P.K.M.O.B.); (T.A.D.S.)
| | - Andre Moreira Pessoni
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (C.P.R.); (A.M.P.)
| | | | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (C.P.R.); (A.M.P.)
- Correspondence:
| |
Collapse
|
5
|
Chu TH, Patz EF, Ackerman ME. Coming together at the hinges: Therapeutic prospects of IgG3. MAbs 2021; 13:1882028. [PMID: 33602056 PMCID: PMC7899677 DOI: 10.1080/19420862.2021.1882028] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/08/2021] [Accepted: 01/22/2021] [Indexed: 01/22/2023] Open
Abstract
The human IgG3 subclass is conspicuously absent among the formats for approved monoclonal antibody therapies and Fc fusion protein biologics. Concern about the potential for rapid degradation, reduced plasma half-life, and increased immunogenicity due to marked variation in allotypes has apparently outweighed the potential advantages of IgG3, which include high affinity for activating Fcγ receptors, effective complement fixation, and a long hinge that appears better suited for low abundance targets. This review aims to highlight distinguishing features of IgG3 and to explore its functional role in the immune response. We present studies of natural immunity and recombinant antibody therapies that elucidate key contributions of IgG3 and discuss historical roadblocks that no longer remain clearly relevant. Collectively, this body of evidence motivates thoughtful reconsideration of the clinical advancement of this distinctive antibody subclass for treatment of human diseases. Abbreviations: ADCC - Antibody-Dependent Cell-mediated CytotoxicityADE - Antibody-dependent enhancementAID - Activation-Induced Cytidine DeaminaseCH - Constant HeavyCHF - Complement factor HCSR - Class Switch RecombinationEM - Electron MicroscopyFab - Fragment, antigen bindingFc - Fragment, crystallizableFcRn - Neonatal Fc ReceptorFcγR - Fc gamma ReceptorHIV - Human Immunodeficiency VirusIg - ImmunoglobulinIgH - Immunoglobulin Heavy chain geneNHP - Non-Human Primate.
Collapse
Affiliation(s)
- Thach H. Chu
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA
| | - Edward F. Patz
- Department of Radiology and Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | | |
Collapse
|
6
|
Ulrich S, Ebel F. Monoclonal Antibodies as Tools to Combat Fungal Infections. J Fungi (Basel) 2020; 6:jof6010022. [PMID: 32033168 PMCID: PMC7151206 DOI: 10.3390/jof6010022] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
Antibodies represent an important element in the adaptive immune response and a major tool to eliminate microbial pathogens. For many bacterial and viral infections, efficient vaccines exist, but not for fungal pathogens. For a long time, antibodies have been assumed to be of minor importance for a successful clearance of fungal infections; however this perception has been challenged by a large number of studies over the last three decades. In this review, we focus on the potential therapeutic and prophylactic use of monoclonal antibodies. Since systemic mycoses normally occur in severely immunocompromised patients, a passive immunization using monoclonal antibodies is a promising approach to directly attack the fungal pathogen and/or to activate and strengthen the residual antifungal immune response in these patients.
Collapse
|
7
|
Methamphetamine Impairs IgG1-Mediated Phagocytosis and Killing of Cryptococcus neoformans by J774.16 Macrophage- and NR-9640 Microglia-Like Cells. Infect Immun 2019; 87:IAI.00113-18. [PMID: 30510106 DOI: 10.1128/iai.00113-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 11/27/2018] [Indexed: 01/14/2023] Open
Abstract
The prevalence of methamphetamine (METH) use is estimated at ∼35 million people worldwide, with over 10 million users in the United States. Chronic METH abuse and dependence predispose the users to participate in risky behaviors that may result in the acquisition of HIV and AIDS-related infections. Cryptococcus neoformans is an encapsulated fungus that causes cryptococcosis, an opportunistic infection that has recently been associated with drug users. METH enhances C. neoformans pulmonary infection, facilitating its dissemination and penetration into the central nervous system in mice. C. neoformans is a facultative intracellular microorganism and an excellent model to study host-pathogen interactions. METH compromises phagocyte effector functions, which might have deleterious consequences on infection control. In this study, we investigated the role of METH in phagocytosis and antigen processing by J774.16 macrophage- and NR-9460 microglia-like cells in the presence of a specific IgG1 to C. neoformans capsular polysaccharide. METH inhibits antibody-mediated phagocytosis of cryptococci by macrophages and microglia, likely due to reduced expression of membrane-bound Fcγ receptors. METH interferes with phagocytic cells' phagosomal maturation, resulting in impaired fungal control. Phagocytic cell reduction in nitric oxide production during interactions with cryptococci was associated with decreased levels of tumor necrosis factor alpha (TNF-α) and lowered expression of Fcγ receptors. Importantly, pharmacological levels of METH in human blood and organs are cytotoxic to ∼20% of the phagocytes. Our findings suggest that METH abrogates immune cellular and molecular functions and may be deadly to phagocytic cells, which may result in increased susceptibility of users to acquire infectious diseases.
Collapse
|
8
|
Wieland A, Ahmed R. Fc Receptors in Antimicrobial Protection. Curr Top Microbiol Immunol 2019; 423:119-150. [DOI: 10.1007/82_2019_154] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
9
|
Lu LL, Suscovich TJ, Fortune SM, Alter G. Beyond binding: antibody effector functions in infectious diseases. Nat Rev Immunol 2018; 18:46-61. [PMID: 29063907 PMCID: PMC6369690 DOI: 10.1038/nri.2017.106] [Citation(s) in RCA: 533] [Impact Index Per Article: 76.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Antibodies play an essential role in host defence against pathogens by recognizing microorganisms or infected cells. Although preventing pathogen entry is one potential mechanism of protection, antibodies can control and eradicate infections through a variety of other mechanisms. In addition to binding and directly neutralizing pathogens, antibodies drive the clearance of bacteria, viruses, fungi and parasites via their interaction with the innate and adaptive immune systems, leveraging a remarkable diversity of antimicrobial processes locked within our immune system. Specifically, antibodies collaboratively form immune complexes that drive sequestration and uptake of pathogens, clear toxins, eliminate infected cells, increase antigen presentation and regulate inflammation. The diverse effector functions that are deployed by antibodies are dynamically regulated via differential modification of the antibody constant domain, which provides specific instructions to the immune system. Here, we review mechanisms by which antibody effector functions contribute to the balance between microbial clearance and pathology and discuss tractable lessons that may guide rational vaccine and therapeutic design to target gaps in our infectious disease armamentarium.
Collapse
Affiliation(s)
- Lenette L Lu
- Ragon Institute of MGH, MIT and Harvard, 400 Technology Square, Cambridge, Massachusetts 02139, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Todd J Suscovich
- Ragon Institute of MGH, MIT and Harvard, 400 Technology Square, Cambridge, Massachusetts 02139, USA
| | - Sarah M Fortune
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Galit Alter
- Ragon Institute of MGH, MIT and Harvard, 400 Technology Square, Cambridge, Massachusetts 02139, USA
| |
Collapse
|
10
|
Naqvi AR, Fordham JB, Nares S. MicroRNA target Fc receptors to regulate Ab-dependent Ag uptake in primary macrophages and dendritic cells. Innate Immun 2016; 22:510-21. [PMID: 27449126 DOI: 10.1177/1753425916661042] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 06/24/2016] [Indexed: 12/23/2022] Open
Abstract
Phagocytosis commences with particle internalization and culminates with the activation of innate and adaptive immune responses. However, the role of miRNAs in phagocytosis remains largely unknown. In this study, we examined the role of miR-24, miR-30b and miR-142-3p in Ab Fc receptor (FcR)-mediated phagocytosis by macrophages (MΦ) and dendritic cells (DC). The expression of these miRNAs was reduced following phagocytosis of both IgG-opsonized beads and Escherichia coli, indicating their regulatory role in the process. Further, overexpression of these miRNAs impaired the uptake of IgG-coated latex beads, which corroborated the reduced secretion of the pro-inflammatory cytokines TNF-α and IL-8 and down-regulation of PKC-α, as well as superoxide-generating enzyme NADPH oxidase 2 expression level. Mechanistically, MΦ and DC transfected with miRNA mimics show marked reduction in expression of FcRs including FCGR2A, FcɛR1G and FCER2. We show that FcɛR1G expression is not affected at the transcription level, rather it is post-transcriptionally regulated by miR-30b. Finally, we demonstrate that siRNA-mediated knockdown of FcɛR1G leads to reduced uptake of IgG-opsonized beads, indicating its involvement on Ab-mediated phagocytosis. These results uncover miR-24, miR-30b and miR-142-3p as an essential component of FcR-mediated phagocytosis and associated innate immune responses.
Collapse
Affiliation(s)
- Afsar Raza Naqvi
- Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA
| | - Jezrom B Fordham
- Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA
| | - Salvador Nares
- Department of Periodontics, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
11
|
Kanayama M, Shinohara ML. Roles of Autophagy and Autophagy-Related Proteins in Antifungal Immunity. Front Immunol 2016; 7:47. [PMID: 26925060 PMCID: PMC4757664 DOI: 10.3389/fimmu.2016.00047] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/31/2016] [Indexed: 12/21/2022] Open
Abstract
Autophagy was initially characterized as a process to digest cellular components, including damaged cell organelles or unused proteins. However, later studies showed that autophagy plays an important role to protect hosts from microbial infections. Accumulating evidences showed the contribution of autophagy itself and autophagy-related proteins (ATGs) in the clearance of bacteria, virus, and parasites. A number of studies also revealed the molecular mechanisms by which autophagy is initiated and developed. Furthermore, it is now understood that some ATGs are shared between two distinct processes; autophagy and LC3-associated phagocytosis (LAP). Thus, our understanding on autophagy has been greatly enhanced in the last decade. By contrast, roles of autophagy and ATGs in fungal infections are still elusive relative to those in bacterial and viral infections. Based on limited numbers of reports, ATG-mediated host responses appear to significantly vary depending on invading fungal species. In this review, we discuss how autophagy and ATGs are involved in antifungal immune responses based on recent discoveries.
Collapse
Affiliation(s)
- Masashi Kanayama
- Department of Immunology, Duke University School of Medicine , Durham, NC , USA
| | - Mari L Shinohara
- Department of Immunology, Duke University School of Medicine, Durham, NC, USA; Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| |
Collapse
|
12
|
Abstract
Cryptococcosis is caused by the fungal genus Cryptococcus. Cryptococcosis, predominantly meningoencephalitis, emerged with the HIV pandemic, primarily afflicting HIV-infected patients with profound T-cell deficiency. Where in use, combination antiretroviral therapy has markedly reduced the incidence of and risk for disease, but cryptococcosis continues to afflict those without access to therapy, particularly in sub-Saharan Africa and Asia. However, cryptococcosis also occurs in solid organ transplant recipients and patients with other immunodeficiencies as well as those with no known immunodeficiency. This article reviews innate and adaptive immune responses to C. neoformans, with an emphasis on recent studies on the role of B cells, natural IgM and Fc gamma receptor polymorphisms in resistance to cryptococcosis.
Collapse
Affiliation(s)
- Soma Rohatgi
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | | |
Collapse
|
13
|
Chan J, Mehta S, Bharrhan S, Chen Y, Achkar JM, Casadevall A, Flynn J. The role of B cells and humoral immunity in Mycobacterium tuberculosis infection. Semin Immunol 2014; 26:588-600. [PMID: 25458990 PMCID: PMC4314354 DOI: 10.1016/j.smim.2014.10.005] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 12/24/2022]
Abstract
Mycobacterium tuberculosis remains a major public health burden. It is generally thought that while B cell- and antibody-mediated immunity plays an important role in host defense against extracellular pathogens, the primary control of intracellular microbes derives from cellular immune mechanisms. Studies on the immune regulatory mechanisms during infection with M. tuberculosis, a facultative intracellular organism, has established the importance of cell-mediated immunity in host defense during tuberculous infection. Emerging evidence suggest a role for B cell and humoral immunity in the control of intracellular pathogens, including obligatory species, through interactions with the cell-mediated immune compartment. Recent studies have shown that B cells and antibodies can significantly impact on the development of immune responses to the tubercle bacillus. In this review, we present experimental evidence supporting the notion that the importance of humoral and cellular immunity in host defense may not be entirely determined by the niche of the pathogen. A comprehensive approach that examines both humoral and cellular immunity could lead to better understanding of the immune response to M. tuberculosis.
Collapse
Affiliation(s)
- John Chan
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Departments of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Simren Mehta
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Departments of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Sushma Bharrhan
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Departments of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Yong Chen
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Departments of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jacqueline M Achkar
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Arturo Casadevall
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA; Departments of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - JoAnne Flynn
- Departments of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| |
Collapse
|
14
|
Abstract
Antibodies are major molecular effectors of adaptive immune responses. Most, if not all, biological activities of antibodies, however, depend on the functional properties of cells that express receptors for the Fc portion of antibodies (FcR). Most FcR are activating receptors; some are inhibitory. When engaged by antibodies and antigen, the various FcR expressed by a given cell trigger a mixture of positive and negative signals whose integration determines cellular responses. Responses of cell populations can be either protective or pathogenic. As a consequence, FcR are potential target/tools in a variety of diseases including infection, allergy, autoimmune diseases, and cancer.
Collapse
|
15
|
Abstract
Cryptococcus neoformans is one of the most common causes of fungal disease in HIV-infected persons, but not all of those who are infected develop cryptococcal disease (CD). Although CD4+ T cell deficiency is a risk factor for HIV-associated CD, polymorphisms of phagocytic Fc gamma receptors (FCGRs) have been linked to CD risk in HIV-uninfected persons. To investigate associations between FCGR2A 131 H/R and FCGR3A 158 F/V polymorphisms and CD risk in HIV-infected persons, we performed PCR-based genotyping on banked samples from 164 men enrolled in the Multicenter AIDS Cohort Study (MACS): 55 who were HIV infected and developed CD and a matched control group of 54 who were HIV infected and 55 who were HIV uninfected. Using additive and allelic statistical models for analysis, the high-affinity FCGR3A 158V allele was significantly associated with CD status after adjusting for race/ethnicity (odds ratio [OR], 2.1; P = 0.005), as was the FCGR3A 158 VV homozygous genotype after adjusting for race/ethnicity, rate of CD4+ T cell decline, and nadir CD4+ T cell count (OR, 21; P = 0.005). No associations between CD and FCGR2A 131 H/R polymorphism were identified. In binding studies, human IgG (hIgG)-C. neoformans complexes exhibited more binding to CHO-K1 cells expressing FCGR3A 158V than to those expressing FCGR3A 158F, and in cytotoxicity assays, natural killer (NK) cells expressing FCGR3A 158V induced more C. neoformans-infected monocyte cytotoxicity than those expressing FCGR3A 158F. Together, these results show an association between the FCGR3A 158V allele and risk for HIV-associated CD and suggest that this polymorphism could promote C. neoformans pathogenesis via increased binding of C. neoformans immune complexes, resulting in increased phagocyte cargo and/or immune activation. HIV-associated CD4+ T cell deficiency is a sine qua non for HIV-associated cryptococcal disease (CD), but not all patients with CD4+ T cell deficiency develop CD despite serological evidence of previous infection. At present, there are no biomarkers that predict HIV-associated CD risk. The goal of our study was to understand whether Fc gamma receptor (FCGR) polymorphisms that have been shown to portend CD risk in HIV-uninfected people are associated with CD risk in HIV-infected people. Such biomarkers could identify those who would benefit most from targeted prophylaxis and/or earlier treatment, particularly in sub-Saharan Africa, where there are nearly a million cases of HIV-associated CD annually. A biomarker of risk could also identify potential candidates for immunization, should there be a vaccine for Cryptococcus neoformans.
Collapse
|
16
|
Kozakiewicz L, Phuah J, Flynn J, Chan J. The role of B cells and humoral immunity in Mycobacterium tuberculosis infection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 783:225-50. [PMID: 23468112 DOI: 10.1007/978-1-4614-6111-1_12] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tuberculosis (TB) remains a serious threat to public health, causing 2 million deaths annually world-wide. The control of TB has been hindered by the requirement of long duration of treatment involving multiple chemotherapeutic agents, the increased susceptibility to Mycobacterium tuberculosis infection in the HIV-infected population, and the development of multi-drug resistant and extensively resistant strains of tubercle bacilli. An efficacious and cost-efficient way to control TB is the development of effective anti-TB vaccines. This measure requires thorough understanding of the immune response to M. tuberculosis. While the role of cell-mediated immunity in the development of protective immune response to the tubercle bacillus has been well established, the role of B cells in this process is not clearly understood. Emerging evidence suggests that B cells and humoral immunity can modulate the immune response to various intracellular pathogens, including M. tuberculosis. These lymphocytes form conspicuous aggregates in the lungs of tuberculous humans, non-human primates, and mice, which display features of germinal center B cells. In murine TB, it has been shown that B cells can regulate the level of granulomatous reaction, cytokine production, and the T cell response. This chapter discusses the potential mechanisms by which specific functions of B cells and humoral immunity can shape the immune response to intracellular pathogens in general, and to M. tuberculosis in particular. Knowledge of the B cell-mediated immune response to M. tuberculosis may lead to the design of novel strategies, including the development of effective vaccines, to better control TB.
Collapse
Affiliation(s)
- Lee Kozakiewicz
- Department of Medicine and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | | | | |
Collapse
|
17
|
Abstract
Coxiella burnetii is an obligate intracellular bacterium that causes a worldwide zoonotic disease, Q fever. Since C. burnetii infection could develop into severe chronic disease in humans, vaccination is the logical approach to prevent individuals at risk of natural and deliberate exposure. Although formalin-inactivated C. burnetii phase I vaccine (PIV) is effective in protecting vaccinated host against the infection in humans, widespread use of this vaccine is limited by its high incidence of adverse reactions, especially in individuals with prior immunity to the agent. Creation of a safe and effective vaccine to prevent Q fever remains an important goal for public health and international biosecurity. It is critical to clearly understand the mechanisms that involved in development of protective immunity against C. burnetii infection and to identify the key protective antigens for developing a safe and effective new generation vaccine against Q fever. This chapter describes new information related to the characterization of acquired immunity to C. burnetii vaccination and infection that will provide a fundamental understanding of the development of protective immunity against Q fever.
Collapse
|
18
|
Ghosh S, Hoselton SA, Schuh JM. Characterization of CD19(+)CD23(+)B2 lymphocytes in the allergic airways of BALB/c mice in response to the inhalation of Aspergillus fumigatus conidia. ACTA ACUST UNITED AC 2012; 5:46-54. [PMID: 23316260 DOI: 10.2174/1874226201205010046] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Fungal sensitization in patients with asthma often indicates an unusual disease course in which traditional asthma treatments have little effect and in which morbidity is particularly severe. Airway hyperresponsiveness (AHR), inflammatory infiltrates, smooth muscle hyperplasia, and irreversible fibrotic remodeling of the bronchial architecture are features of allergic fungal asthma. The systemic production of IgE has long been associated with the immunopathogenesis of allergic asthma; however, the role of B lymphocytes and their products in the response to fungal allergens remains unclear. In the present study, we hypothesize that B lymphocytes are recruited to the allergic lung to impact the allergic response. Using a murine fungal aeroallergen model to mimic the human syndrome, we characterized the B cell population in the lung after fungal challenge and found that CD19(+)CD23(+) B2 lymphocyte numbers are increased in the allergic lung in a dynamic process. IgA, IgG(2a), and IgE were prominent in the serum and bronchoalveolar lavage fluid of allergic animals. It was evident that a tissue-centric production of these antibodies was possible. IgA-, IgG-, and IgE-producing cells from the allergic lung were identified by flow cytometry and immunohistochemistry. This study shows for the first time that CD19(+)CD23(+) B2 lymphocyte numbers change in the lung in a dynamic process after inhalation of fungal conidia and their increase has a significant impact on the Ab production in the pulmonary compartment in the context of fungal allergy.
Collapse
Affiliation(s)
- Sumit Ghosh
- Department of Veterinary and Microbiological Sciences, North Dakota State University, Fargo, ND 58108, USA
| | | | | |
Collapse
|
19
|
Belzer C, Liu Q, Carroll MC, Bry L. THE ROLE OF SPECIFIC IgG AND COMPLEMENT IN COMBATING A PRIMARY MUCOSAL INFECTION OF THE GUT EPITHELIUM. Eur J Microbiol Immunol (Bp) 2011; 1:311-318. [PMID: 22485193 DOI: 10.1556/eujmi.1.2011.4.7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The role of complement and complement-fixing IgG isotypes at mucosal surfaces is ill defined. Previous data have demonstrated that survival of an infection with the attaching and effacing pathogen Citrobacter rodentium requires production of systemic and CD4+ T cell-dependent IgG. We have found that both complement and complement-fixing IgG isotypes are needed to survive a C. rodentium infection. Our results indicate that both IgG and complement C3b enter the gut lumen and bind epithelially adherent, and fecally shed C. rodentium. Furthermore, C3-deficient mice demonstrate a profound survival defect, though means to replenish C3 in systemic or mucosal sites restores the protective capacity of complement in the host. Our data provide evidence that both IgG and complement interact constructively on both sides of the epithelium to fight colonizing mucosal infections.
Collapse
Affiliation(s)
- C Belzer
- Department of Pathology, Harvard University Medical School/Brigham and Women's Hospital, Boston, MA 02115, USA
| | | | | | | |
Collapse
|
20
|
Joller N, Weber SS, Oxenius A. Antibody - Fc receptor interactions in protection against intracellular pathogens. Eur J Immunol 2011; 41:889-97. [DOI: 10.1002/eji.201041340] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/21/2011] [Accepted: 03/02/2011] [Indexed: 01/12/2023]
|
21
|
Eslava I, Payares G, Pernia BM, Holder AA, Spencer LM. Suppressive and additive effects in protection mediated by combinations of monoclonal antibodies specific for merozoite surface protein 1 of Plasmodium yoelii. Malar J 2010; 9:46. [PMID: 20146804 PMCID: PMC2834700 DOI: 10.1186/1475-2875-9-46] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 02/10/2010] [Indexed: 11/29/2022] Open
Abstract
Background The merozoite surface protein (MSP)-1 is a target antigen of protective immunity and a malaria vaccine candidate. The nature of this protective immune response warrants further investigation: although specific antibody is thought to play a major role, the mechanisms of protection are still unclear. Monoclonal antibodies (mAbs) specific for the C-terminus of MSP-1 from Plasmodium yoelii have been shown previously to provide protection against challenge infection when administered by passive immunization to mice. Three protective mAbs were re-examined and, in particular, the effect of combinations of antibodies on the protection provided was studied. It was found that a combination of two antibodies can either provide additive protective effects or result in a suppression of protection. In this report the importance of antibody subclass and epitope specificity in the outcome of these passive immunization experiments are discussed. Methods The minimum protective dose (MPD) for each mAb was determined, and then combinations of antibody at their MPD were investigated for their ability to control parasitaemia and promote survival in groups of mice. Mice were inoculated over three days with the MPD and challenged with a blood stage infection of the virulent P. yoelii 17 XL. The resultant parasitaemia was assessed daily on Giemsa-stained blood films. Following the infection the presence of MSP-1 specific antibodies in the sera was monitored, and the proliferative responses of cells in the spleen of protected mice were measured. Results Combining antibodies resulted in either an additive effect on protection, with reduced peak parasitaemia and better survival, or resulted in a suppression of protection over that achieved by a single antibody alone. An additive effect was observed when B6 and F5 that have the same isotype and similar fine specificity, were combined. However, a combination of mAb D3, an IgG2a, with either B6 or F5 (both IgG3) suppressed protection, an effect that may have been due to the combination of different isotypes or to the different fine specificity of the antibodies. Conclusions These results suggest that a combination of protective antibodies with either the same or different isotypes can produce either an additive or a suppressive effect in passive immunization. This phenomenon may be important in better understanding immunity in this experimental mouse model of malaria.
Collapse
Affiliation(s)
- Irosoki Eslava
- Department of Cell Biology, Simón Bolívar University, AP 89000, Caracas, Venezuela
| | | | | | | | | |
Collapse
|
22
|
Saylor CA, Dadachova E, Casadevall A. Murine IgG1 and IgG3 isotype switch variants promote phagocytosis of Cryptococcus neoformans through different receptors. THE JOURNAL OF IMMUNOLOGY 2009; 184:336-43. [PMID: 19949107 DOI: 10.4049/jimmunol.0902752] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Almost 3 decades ago, murine IgG3 was proposed to interact with a different receptor than the other IgG subclasses, but the issue remains unresolved. The question of whether a specific receptor exists for IgG3 is critically important for understanding Ab-mediated immunity against Cryptococcus neoformans, where the different isotypes manifest profound differences in protective efficacy. In this study, we revisited this question by analyzing IgG1- and IgG3-mediated phagocytosis with variable region-identical mAbs using mouse macrophages deficient in various receptors and in conditions of FcgammaR and complement receptor blockage with specific Abs. IgG3 was an efficient opsonin for C. neoformans in FcgammaR- and CD18-deficient cells and in the presence of blocking Abs to FcgammaR and complement receptor. Like IgG1, IgG3-mediated phagocytosis was associated with fungal residence in a mature phagosome that was followed by intracellular replication and exocytosis events. We conclude that a specific receptor for IgG3 exists in mice that is structurally different from the known FcgammaRs.
Collapse
Affiliation(s)
- Carolyn A Saylor
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | |
Collapse
|
23
|
Abstract
The complexity and number of antigens (Ags) seen during an immune response has hampered the development of malaria vaccines. Antibodies (Abs) play an important role in immunity to malaria and their passive administration is effective at controlling the disease. Abs represent approximately 25% of all proteins undergoing clinical trials, and these 'smart biologicals' have undergone a major revival with the realization that Abs lie at the interface between innate and adaptive immunity. At least 18 Abs have FDA approval for clinical use and approximately 150 are in clinical trials, the majority for the treatment of cancer, allograft rejection or autoimmune disease. Despite these triumphs none are in development for malaria, principally because they are perceived as being too expensive for a disease mainly afflicting poor and marginalized populations. Although unlikely, at least in the foreseeable future, that Ab-based prophylaxis will be made available to the millions of people at risk from malaria, they may be incorporated into current vaccine approaches, since Abs act as correlates of protection in studies aimed at defining the best Ags to include in vaccines. Abs may also form the basis for novel vaccination strategies by targeting Ags to appropriate antigen presenting cells. Therefore, to develop the most efficacious vaccines it will be necessary to fully understand which Abs and Fc-receptors (FcRs) are best engaged for a positive outcome.
Collapse
Affiliation(s)
- R J Pleass
- Institute of Genetics, Queen's Medical Centre, Nottingham NG7 2UH, UK.
| |
Collapse
|
24
|
Pleass RJ, Behnke JM. B-cells get the T-cells but antibodies get the worms. Trends Parasitol 2009; 25:443-6. [PMID: 19734092 PMCID: PMC3115547 DOI: 10.1016/j.pt.2009.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 06/23/2009] [Accepted: 07/08/2009] [Indexed: 01/06/2023]
Abstract
Two recent papers published in Immunity and Cell Host & Microbe underline the great importance of B cells and of antibodies (Abs) in orchestrating crucial T helper cell type 2 (Th2) protective immune responses to gastrointestinal nematodes. The findings in animal models now raise major questions as to how B cells and Abs carry out these functions in humans. Here we discuss recent technological advances in humanizing animal models at the level of both Abs and their Fc-receptors, that might provide some answers.
Collapse
Affiliation(s)
- Richard J Pleass
- Institute of Genetics, and Parasite Biology and Immunogenetics Research Group, Queen's Medical Centre, University of Nottingham, NG7 2UH, UK.
| | | |
Collapse
|
25
|
The capsule of the fungal pathogen Cryptococcus neoformans. ADVANCES IN APPLIED MICROBIOLOGY 2009; 68:133-216. [PMID: 19426855 DOI: 10.1016/s0065-2164(09)01204-0] [Citation(s) in RCA: 332] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The capsule of the fungal pathogen Cryptococcus neoformans has been studied extensively in recent decades and a large body of information is now available to the scientific community. Well-known aspects of the capsule include its structure, antigenic properties and its function as a virulence factor. The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), in addition to a smaller proportion of mannoproteins (MPs). Most of the studies on the composition of the capsule have focused on GXM, which comprises more than 90% of the capsule's polysaccharide mass. It is GalXM, however, that is of particular scientific interest because of its immunological properties. The molecular structure of these polysaccharides is very complex and has not yet been fully elucidated. Both GXM and GalXM are high molecular mass polymers with the mass of GXM equaling roughly 10 times that of GalXM. Recent findings suggest, however, that the actual molecular weight might be different to what it has traditionally been thought to be. In addition to their structural roles in the polysaccharide capsule, these molecules have been associated with many deleterious effects on the immune response. Capsular components are therefore considered key virulence determinants in C. neoformans, which has motivated their use in vaccines and made them targets for monoclonal antibody treatments. In this review, we will provide an update on the current knowledge of the C. neoformans capsule, covering aspects related to its structure, synthesis and particularly, its role as a virulence factor.
Collapse
|
26
|
Maglione PJ, Chan J. How B cells shape the immune response against Mycobacterium tuberculosis. Eur J Immunol 2009; 39:676-86. [PMID: 19283721 DOI: 10.1002/eji.200839148] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Extensive work illustrating the importance of cellular immune mechanisms for protection against Mycobacterium tuberculosis has largely relegated B-cell biology to an afterthought within the tuberculosis (TB) field. However, recent studies have illustrated that B lymphocytes, through a variety of interactions with the cellular immune response, play previously underappreciated roles in shaping host defense against non-viral intracellular pathogens, including M. tuberculosis. Work in our laboratory has recently shown that, by considering these lymphocytes more broadly within their variety of interactions with cellular immunity, B cells have a significant impact on the outcome of airborne challenge with M. tuberculosis as well as the resultant inflammatory response. In this review, we advocate for a revised view of TB immunology in which roles of cellular and humoral immunity are not mutually exclusive. In the context of our current understanding of host defense against non-viral intracellular infections, we review recent data supporting a more significant role of B cells during M. tuberculosis infection than previously thought.
Collapse
Affiliation(s)
- Paul J Maglione
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, NY, USA
| | | |
Collapse
|
27
|
McIntosh RS, Shi J, Jennings RM, Chappel JC, de Koning-Ward TF, Smith T, Green J, van Egmond M, Leusen JHW, Lazarou M, van de Winkel J, Jones TS, Crabb BS, Holder AA, Pleass RJ. The importance of human FcgammaRI in mediating protection to malaria. PLoS Pathog 2007; 3:e72. [PMID: 17511516 PMCID: PMC1868954 DOI: 10.1371/journal.ppat.0030072] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 04/04/2007] [Indexed: 11/20/2022] Open
Abstract
The success of passive immunization suggests that antibody-based therapies will be effective at controlling malaria. We describe the development of fully human antibodies specific for Plasmodium falciparum by antibody repertoire cloning from phage display libraries generated from immune Gambian adults. Although these novel reagents bind with strong affinity to malaria parasites, it remains unclear if in vitro assays are predictive of functional immunity in humans, due to the lack of suitable animal models permissive for P. falciparum. A potentially useful solution described herein allows the antimalarial efficacy of human antibodies to be determined using rodent malaria parasites transgenic for P. falciparum antigens in mice also transgenic for human Fc-receptors. These human IgG1s cured animals of an otherwise lethal malaria infection, and protection was crucially dependent on human FcγRI. This important finding documents the capacity of FcγRI to mediate potent antimalaria immunity and supports the development of FcγRI-directed therapy for human malaria. Malaria rivals HIV and tuberculosis as the world's most deadly infection killing a child every 30 seconds. Antibodies and their receptors (Fc-receptors) have been shown to be vital for the development of protective immunity, and as such they act as correlates of protection in studies aimed at defining the best antigens to incorporate into current vaccines. Understanding antibody types and Fc-receptors that optimally induce immunity is therefore vital to developing the best vaccines. Surrogate markers of antibody efficacy currently rely on in vitro assays that are laborious and difficult to reproduce. It remains unclear if such in vitro assays are predictive of functional immunity in humans due to the lack of suitable animal models permissive for Plasmodium falciparum. Here, we create a transgenic in vivo mouse model that has significant advantage over the use of new world primates, the only other model for human malaria. We demonstrate that this model defines an Fc-dependent mechanism of parasite destruction that cannot be assessed in current in vitro assays. The model provides both a test for therapeutic antibody efficacy prior to clinical trials in humans and an important tool in malaria vaccine development.
Collapse
Affiliation(s)
- Richard S McIntosh
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Jianguo Shi
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Richard M Jennings
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
| | - Jonathan C Chappel
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
- Medical Research Council Technology, London, United Kingdom
| | | | - Tim Smith
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Judith Green
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
| | - Marjolein van Egmond
- Department of Molecular Cell Biology and Immunology, VU Medical Centre, Amsterdam, Netherlands
| | - Jeanette H. W Leusen
- Immunotherapy Laboratory, Department of Immunology, University Medical Centre Utrecht, Utrecht, Netherlands
| | - Maria Lazarou
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
| | - Jan van de Winkel
- Immunotherapy Laboratory, Department of Immunology, University Medical Centre Utrecht, Utrecht, Netherlands
- Genmab, Utrecht, Netherlands
| | - Tarran S Jones
- Medical Research Council Technology, London, United Kingdom
| | - Brendan S Crabb
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Anthony A Holder
- Division of Parasitology, National Institute for Medical Research, Medical Research Council, London, United Kingdom
- * To whom correspondence should be addressed. E-mail: (AAH); (RJP)
| | - Richard J Pleass
- Institute of Genetics, Queen's Medical Centre, University of Nottingham, United Kingdom
- * To whom correspondence should be addressed. E-mail: (AAH); (RJP)
| |
Collapse
|
28
|
Beenhouwer DO, Yoo EM, Lai CW, Rocha MA, Morrison SL. Human immunoglobulin G2 (IgG2) and IgG4, but not IgG1 or IgG3, protect mice against Cryptococcus neoformans infection. Infect Immun 2007; 75:1424-35. [PMID: 17220317 PMCID: PMC1828574 DOI: 10.1128/iai.01161-06] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The encapsulated yeast Cryptococcus neoformans is a significant cause of meningitis and death in patients with AIDS. Some murine monoclonal antibodies (MAbs) against the glucuronoxylomannan (GXM) component of the C. neoformans capsular polysaccharide can prolong the lives of infected mice, while others have no effect or can even shorten survival. To date, no one has systematically compared the efficacies of antibodies with the same variable regions and different human constant regions with their unique combination of effector functions in providing protection against murine C. neoformans infection. In the present study, we examined the efficacies of anti-GXM MAbs of the four human immunoglobulin G (IgG) subclasses, which have identical variable regions but differ in their capacities to bind the three types of Fc receptors for IgG (FcgammaR), their abilities to activate complement, and their half-lives. IgG2 and IgG4 anti-GXM prolonged the lives of infected BALB/c mice, IgG3 anti-GXM did not affect animal survival, while mice treated with IgG1 anti-GXM died earlier than mice treated with phosphate-buffered saline or irrelevant isotype-matched MAbs. All MAbs decreased serum GXM in infected animals. Effector pathways traditionally believed to be important in defense against microbes, such as opsonophagocytosis and complement binding, negatively correlated with antibody efficacy. It is generally accepted that human IgG1 has the most favorable combination of effector functions for therapeutic use against infections. Therefore, our findings have significant implications for humanization of the mouse IgG1 currently in clinical trials for cryptococcal meningitis and for the design of antibody therapeutics to treat other infectious diseases as well.
Collapse
Affiliation(s)
- David O Beenhouwer
- Division of Infectious Diseases, Veterans Affairs Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA.
| | | | | | | | | |
Collapse
|
29
|
Meletiadis J, Walsh TJ, Choi EH, Pappas PG, Ennis D, Douglas J, Pankey GA, Larsen RA, Hamill RJ, Chanock S. Study of common functional genetic polymorphisms ofFCGR2A,3Aand3Bgenes and the risk for cryptococcosis in HIV-uninfected patients. Med Mycol 2007; 45:513-8. [PMID: 17710620 DOI: 10.1080/13693780701390140] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
A pilot candidate gene association study was conducted to investigate the role of three common functional genetic polymorphisms of the low-affinity Fc gamma receptors, FCGR2A (131H/R), FCGR3A (158F/V) and FCGR3B (NA1/NA2) in Cryptococcus neoformans infections in individuals not infected with HIV. The FCGR2A 131RR and FCGR3A 158VV genotypes were over-represented [OR: 1.67 (1.05-2.63) and 2.04 (1.06-4.00), respectively] whereas the FCGR3B NA2NA2 was under-represented in patients with cryptococcosis (28% vs. 40% in controls). An analysis of haplotypes showed a significant difference in distribution between cases and controls overall and in Caucasians.
Collapse
|
30
|
Yauch LE, Lam JS, Levitz SM. Direct inhibition of T-cell responses by the Cryptococcus capsular polysaccharide glucuronoxylomannan. PLoS Pathog 2006; 2:e120. [PMID: 17096589 PMCID: PMC1635532 DOI: 10.1371/journal.ppat.0020120] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 09/25/2006] [Indexed: 12/14/2022] Open
Abstract
The major virulence factor of the pathogenic fungi Cryptococcus neoformans and C. gattii is the capsule. Glucuronoxylomannan (GXM), the major component of the capsule, is a high-molecular-weight polysaccharide that is shed during cryptococcosis and can persist in patients after successful antifungal therapy. Due to the importance of T cells in the anticryptococcal response, we studied the effect of GXM on the ability of dendritic cells (DCs) to initiate a T-cell response. GXM inhibited the activation of cryptococcal mannoprotein–specific hybridoma T cells and the proliferation of OVA-specific OT-II T cells when murine bone marrow–derived DCs were used as antigen-presenting cells. Inhibition of OT-II T-cell proliferation was observed when either OVA protein or OVA323–339 peptide was used as antigen, indicating GXM did not merely prevent antigen uptake or processing. We found that DCs internalize GXM progressively over time; however, the suppressive effect did not require DCs, as GXM directly inhibited T-cell proliferation induced by anti-CD3 antibody, concanavalin A, or phorbol-12-myristate-13-acetate/ionomycin. Analysis of T-cell viability revealed that the reduced proliferation in the presence of GXM was not the result of increased cell death. GXM isolated from each of the four major cryptococcal serotypes inhibited the proliferation of human peripheral blood mononuclear cells stimulated with tetanus toxoid. Thus, we have defined a new mechanism by which GXM can impart virulence: direct inhibition of T-cell proliferation. In patients with cryptococcosis, this could impair optimal cell-mediated immune responses, thereby contributing to the persistence of cryptococcal infections. Infections due to the pathogenic yeast Cryptococcus are a significant cause of morbidity and mortality in persons with impaired T-cell functions, particularly those with AIDS. The major virulence factor of Cryptococcus is its capsule, which is composed primarily of the polysaccharide glucuronoxylomannan (GXM). The capsule not only surrounds the organism but also is shed during cryptococcosis. GXM is taken up by macrophages in vitro and in vivo; however, little is known about the interaction between GXM and dendritic cells, which are the most potent cells capable of activating T cells. Because of the importance of T cells in the anticryptococcal response, the authors investigated the effect of GXM on the ability of dendritic cells to initiate a T-cell response. They found the polysaccharide was internalized by dendritic cells and inhibited antigen-specific T-cell responses. Furthermore, GXM had a direct, inhibitory effect on T-cell proliferation, independent of the effect on dendritic cells. These findings may help explain the persistence of cryptococcal infections and suggest that GXM could be therapeutic in situations where suppression of T-cell responses is desired.
Collapse
Affiliation(s)
- Lauren E Yauch
- Departments of Medicine and Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Jennifer S Lam
- Departments of Medicine and Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Stuart M Levitz
- Departments of Medicine and Microbiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
31
|
Wozniak KL, Vyas JM, Levitz SM. In vivo role of dendritic cells in a murine model of pulmonary cryptococcosis. Infect Immun 2006; 74:3817-24. [PMID: 16790753 PMCID: PMC1489690 DOI: 10.1128/iai.00317-06] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dendritic cells (DC) have been shown to phagocytose and kill Cryptococcus neoformans in vitro and are believed to be important for inducing protective immunity against this organism. Exposure to C. neoformans occurs mainly by inhalation, and in this study we examined the in vivo interactions of C. neoformans with DC in the lung. Fluorescently labeled live C. neoformans and heat-killed C. neoformans were administered intranasally to C57BL/6 mice. At specific times postinoculation, mice were sacrificed, and lungs were removed. Single-cell suspensions of lung cells were prepared, stained, and analyzed by microscopy and flow cytometry. Within 2 h postinoculation, fluorescently labeled C. neoformans had been internalized by DC, macrophages, and neutrophils in the mouse lung. Additionally, lung DC from mice infected for 7 days showed increased expression of the maturation markers CD80, CD86, and major histocompatibility complex class II. Finally, ex vivo incubation of lung DC from infected mice with Cryptococcus-specific T cells resulted in increased interleukin-2 production compared to the production by DC from naïve mice, suggesting that there was antigen-specific T-cell activation. This study demonstrated that DC in the lung are capable of phagocytosing Cryptococcus in vivo and presenting antigen to C. neoformans-specific T cells ex vivo, suggesting that these cells have roles in innate and adaptive pulmonary defenses against cryptococcosis.
Collapse
Affiliation(s)
- Karen L Wozniak
- Section of Infectious Diseases, Boston University Medical Center, 650 Albany St., Boston, MA 02118, USA
| | | | | |
Collapse
|
32
|
Abstract
Abs (antibodies) are complex glycoproteins that play a crucial role in protective immunity to malaria, but their effectiveness in mediating resistance can be enhanced by genetically engineered modifications that improve on nature. These Abs also aid investigation of immune mechanisms operating to control the disease and are valuable tools in developing neutralization assays for vaccine design. This review explores how this might be achieved.
Collapse
Affiliation(s)
- Jianguo Shi
- Institute of Genetics, School of Biology, University of Nottingham NG7 2RD, UK
| | | | | |
Collapse
|
33
|
Hjelm F, Carlsson F, Verbeek S, Heyman B. IgG3-mediated enhancement of the antibody response is normal in Fc gammaRI-deficient mice. Scand J Immunol 2006; 62:453-61. [PMID: 16305642 DOI: 10.1111/j.1365-3083.2005.01684.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibodies, administered together with their specific antigen, can feedback-regulate antibody responses to this antigen. IgG1, IgG2a and IgG2b enhance antibody responses to soluble protein antigens. This effect is primarily mediated by FcRs as enhancement is impaired in FcR gamma-/- mice, reported to lack Fc gammaRI and Fc gammaRIII because of deletion of the common FcR gamma chain. Also IgG3 can enhance antibody responses. However, this effect is unperturbed in FcR gamma-/- mice but severely impaired in complement-depleted animals and in animals lacking complement receptor 1 and 2. Although this argues against involvement of Fc gammaRs, FcR gamma-/- mice may express one-fifth of the normal levels of Fc gammaRI and, in addition, Fc gammaRI has been suggested to bind IgG3. We re-investigated the dependence of IgG3-mediated enhancement on Fc gammaRs using a mouse strain selectively lacking Fc gammaRI and found that IgG3-mediated enhancement is completely normal. Unlike IgE and IgG2a, which are both thought to enhance T-cell proliferation via FcR-mediated antigen presentation, IgG3 was a poor enhancer of T-cell proliferation both in vivo and in vitro. These findings argue against a significant involvement of Fc gammaRs in IgG3-mediated enhancement of antibody responses and support our previous conclusion that complement plays a major role.
Collapse
Affiliation(s)
- F Hjelm
- Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | | | | | | |
Collapse
|
34
|
Chapuy-Regaud S, Nogueira L, Clavel C, Sebbag M, Vincent C, Serre G. IgG subclass distribution of the rheumatoid arthritis-specific autoantibodies to citrullinated fibrin. Clin Exp Immunol 2005; 139:542-50. [PMID: 15730401 PMCID: PMC1809305 DOI: 10.1111/j.1365-2249.2004.02708.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In the rheumatoid synovium, deiminated ('citrullinated') forms of fibrin are the major targets of IgG autoantibodies to citrullinated proteins (ACPA), the most specific serological markers of rheumatoid arthritis (RA). To further the characterization of ACPA, we determined their subclass distribution. From a previously validated highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) onto in vitro deiminated human fibrinogen - antihuman fibrin(ogen) autoantibodies (AhFibA)-ELISA - we derived and calibrated four ELISAs, using monoclonal antibodies to each of the four IgG subclasses, to determine the proportions of AhFibA subclasses in the sera. A series of 186 serum samples from RA patients was analysed. All AhFibA-positive sera contained IgG1-AhFibA, which reached the highest titres and accounted for more than 80% of AhFibA in three-quarters of the sera. One or two other subclasses were associated with IgG1 in 39% of the sera, IgG4-AhFibA being observed much more frequently and at higher titres than IgG3- or IgG2-AhFibA. IgG1 alone or IgG(1 + 4)-AhFibA were the AhFibA subclass profiles found in more than 80% of patients. AhFibA are mainly IgG1 and, to a lesser extent, IgG4. Such IgG subclass profiles may influence the effector phases of the immunological conflict between ACPA and deiminated fibrin that takes place specifically in the rheumatoid synovium and therefore may play a critical role in the self-maintenance of rheumatoid inflammation.
Collapse
Affiliation(s)
- S Chapuy-Regaud
- Laboratory of 'Epidermis Differentiation and Rheumatoid Autoimmunity', UMR 5165 CNRS-Toulouse III University, Toulouse, France
| | | | | | | | | | | |
Collapse
|
35
|
Kelly RM, Chen J, Yauch LE, Levitz SM. Opsonic requirements for dendritic cell-mediated responses to Cryptococcus neoformans. Infect Immun 2005; 73:592-8. [PMID: 15618199 PMCID: PMC539000 DOI: 10.1128/iai.73.1.592-598.2005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The encapsulated pathogenic yeast Cryptococcus neoformans is poorly recognized by phagocytic cells in the absence of opsonins. Macrophages will bind and internalize complement- or antibody-opsonized C. neoformans; however, less is known about the role of opsonins in dendritic cell (DC)-mediated recognition of the organism. Thus, we studied the opsonic requirements for binding to C. neoformans by cultured human monocyte-derived and murine bone marrow-derived DCs and whether binding leads to antifungal activity and cytokine release. Binding of unopsonized C. neoformans to human and murine DCs was negligible. Opsonization with pooled human serum (PHS) increased binding, while heat treatment of PHS virtually abolished this binding, thus suggesting a role for heat-labile complement components. PHS plus a monoclonal anticapsular antibody, 3C2, had an additive effect on binding for most cryptococcal strains. Human and murine DCs exhibited pronounced anticryptococcal activity in the presence of the antibody at early (2-h) and late (24-h) time points; however, PHS opsonization did not supplement this anticryptococcal activity. Antifungal activity against C. neoformans opsonized in PHS and/or antibody was partially reduced in the presence of inhibitors of the respiratory burst response. Human, but not murine, DCs released modest amounts of tumor necrosis factor alpha when stimulated with C. neoformans opsonized in PHS and/or antibody. However, opsonized C. neoformans failed to stimulate detectable release of interleukin 10 (IL-10) or IL-12p70 from either DC population. Thus, human and murine DCs show maximal binding to and antifungal activity against C. neoformans via a process highly dependent on opsonization.
Collapse
Affiliation(s)
- Ryan M Kelly
- Room X626, Boston Medical Center, 650 Albany St., Boston, MA 02118, USA
| | | | | | | |
Collapse
|
36
|
Morton HC, Pleass RJ, Storset AK, Dissen E, Williams JL, Brandtzaeg P, Woof JM. Cloning and characterization of an immunoglobulin A Fc receptor from cattle. Immunology 2004; 111:204-11. [PMID: 15027906 PMCID: PMC1782410 DOI: 10.1111/j.0019-2805.2003.01808.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Revised: 11/26/2003] [Accepted: 11/27/2003] [Indexed: 11/29/2022] Open
Abstract
Here, we describe the cloning, sequencing and characterization of an immunoglobulin A (IgA) Fc receptor from cattle (bFcalphaR). By screening a translated EST database with the protein sequence of the human IgA Fc receptor (CD89) we identified a putative bovine homologue. Subsequent polymerase chain reaction (PCR) amplification confirmed that the identified full-length cDNA was expressed in bovine cells. COS-1 cells transfected with a plasmid containing the cloned cDNA bound to beads coated with either bovine or human IgA, but not to beads coated with bovine IgG2 or human IgG. The bFcalphaR cDNA is 873 nucleotides long and is predicted to encode a 269 amino-acid transmembrane glycoprotein composed of two immunoglobulin-like extracellular domains, a transmembrane region and a short cytoplasmic tail devoid of known signalling motifs. Genetically, bFcalphaR is more closely related to CD89, bFcgamma2R, NKp46, and the KIR and LILR gene families than to other FcRs. Moreover, the bFcalphaR gene maps to the bovine leucocyte receptor complex on chromosome 18. Identification of the bFcalphaR will aid in the understanding of IgA-FcalphaR interactions, and may facilitate the isolation of FcalphaR from other species.
Collapse
Affiliation(s)
- H Craig Morton
- Laboratory of Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, University of Oslo, Rikshospitalet, Oslo, Norway.
| | | | | | | | | | | | | |
Collapse
|
37
|
van der Pol WL, Jansen MD, Sluiter WJ, van de Sluis B, Leppers-van de Straat FGJ, Kobayashi T, Westendorp RGJ, Huizinga TWJ, van de Winkel JGJ. Evidence for non-random distribution of Fcgamma receptor genotype combinations. Immunogenetics 2003; 55:240-6. [PMID: 12830330 DOI: 10.1007/s00251-003-0574-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2003] [Revised: 03/17/2003] [Indexed: 10/26/2022]
Abstract
Human IgG receptors (FcgammaR) display considerable heterogeneity, and are crucial immune response modulating molecules. FcgammaRIIA, FcgammaRIIIA, and FcgammaRIIIB display functional biallelic polymorphisms. FcgammaR polymorphisms have been found associated with susceptibility to infectious and autoimmune diseases. Linked transmission of FcgammaR alleles was studied by determining the distribution of FcgammaRIIA-FcgammaRIIIA-FcgammaRIIIB genotype combinations in 514 Dutch Caucasian, and 149 Japanese blood donors. The structure of the FcgammaR locus was studied by radiation hybrid mapping of FcgammaRIA, FcgammaRIIA, FcgammaRIIB, FcgammaRIIIA, FcgammaRIIIB, and adjacent genes from the pentraxin family. In addition, crossing-over frequencies within the FcgammaR locus were determined in 63 Dutch Caucasian families, encompassing 183 individuals. FcgammaRII and FcgammaRIII subclasses were mapped in close proximity (0.47-3.14 cR). Accordingly, crossing-over frequencies within the FcgammaRII-III locus in Dutch families were low. Analysis of combined FcgammaR genotypes strongly suggested non-random distribution of FcgammaRIIA-FcgammaRIIIA-, and FcgammaRIIIA-FcgammaRIIIB genotypes in Dutch donors (P<0.001 and P<0.00001, respectively), and of FcgammaRIIA-FcgammaRIIIb genotypes in Japanese blood donors (P<0.02). Frequencies of FcgammaRII-FcgammaRIII haplotypes differed significantly between Dutch and Japanese (P<0.00001). This study provides important information for the interpretation of studies reporting associations of FcgammaR alleles with disease, and underscores the apparent differences in FcgammaR heterogeneity between ethnic groups.
Collapse
Affiliation(s)
- W-Ludo van der Pol
- Department of Immunology, Laboratory for Immunotherapy, KC.02-085.2, University Medical Center Utrecht, Lundlaan 6, 3584 EA Utrecht, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
In pigs, protection against the toxigenic extra-cellular bacterium Actinobacillus pleuropneumoniae was correlated with an increased IgG(1):IgG(2) ratio of haemolytic toxin-specific antibodies. In all species so far studied, IgG isotype expression is controlled by Type 1 (IFN-gamma, IL-12) and Type 2 (IL-4, IL-10) cytokines which dictate immune response polarization to cell-mediated (CMI) or antibody-mediated immunity (AMI), respectively. Thus, immunoglobulin (Ig) isotypes reflect Type 1 or Type 2 immune responses. Immunoglobulin isotype production by porcine B-cells cultured in the presence of recombinant porcine (rp) cytokines varies by individual, however pigs tend to generate a high IgG(1):IgG(2) ratio in response to rp IL-10 and the inverse in response to rp IFN-gamma or rp IL-12. Differential Ig isotype production should favor an isotype with a functional advantage to control the inciting infection and disease. However, functions of porcine Ig isotypes have not been described. To compare function of porcine IgM, IgG(1) and IgG(2) of defined specificity for hen eggwhite lysozyme (HEWL), Ig isotypes were affinity purified from serum by HEWL specificity and by isotype-specific mouse monoclonal antibodies. Their ability to activate complement (C') and to opsonize was tested in vitro. Porcine IgG(2) had greater guinea pig C' activating ability than did IgG(1). Neither isotype opsonized HEWL-conjugated sheep erythrocytes in vitro. Amino acid sequence analysis of IgG isotypes revealed that all subclasses have putative C' binding sites but that IgG(2a), IgG(2b) and IgG(4) were more flexible in the middle hinge region than IgG(1) and IgG(3) and would likely activate C' more efficiently. Thus, porcine IgG isotypes associated with resistance and susceptibility to disease also differ in their actual and predicted biological functions.
Collapse
Affiliation(s)
- A Crawley
- Department of Pathobiology, University of Guelph, Guelph, Ont., Canada N1G 2W1.
| | | |
Collapse
|
39
|
Hamre R, Farstad IN, Brandtzaeg P, Morton HC. Expression and modulation of the human immunoglobulin A Fc receptor (CD89) and the FcR gamma chain on myeloid cells in blood and tissue. Scand J Immunol 2003; 57:506-16. [PMID: 12791088 DOI: 10.1046/j.1365-3083.2003.01220.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CD89, the human immunoglobulin A (IgA) Fc receptor (FcR), is a potential target for antibody-based therapeutics, but little is known about its expression and modulation in vivo. In this study, we examined the expression pattern of CD89 and its signalling subunit, the FcR gamma chain, on circulating myeloid cells and in various tissues. Our results showed a wide tissue distribution of CD89+ cells. Thus, CD89+ cells were evident as clusters in tonsils and appendix and scattered in varying numbers in lymph nodes, kidney, liver, intestinal mucosa, bronchoalveolar lavage and peritoneal fluid. Most CD89+ cells were identified as neutrophils with high levels of CD89. A few recently emigrated macrophages (CD14low), weakly positive for CD89, were occasionally found in the tissues and more often in the peritoneal fluid. The level of CD89 on neutrophils in tissues and peripheral blood was similar, whereas on monocytes it was much lower in the tissues than in blood, and it was absent on CD14-/CD68+ intestinal lamina propria macrophages. Conversely, we detected much higher levels of the FcR gamma chain in monocytes than in neutrophils, but the FcR gamma chain was also downregulated in tissue macrophages as well as in in vitro-differentiated monocyte-derived macrophages and dendritic cells. The implications of our current findings on the biological functioning of CD89 are discussed.
Collapse
Affiliation(s)
- R Hamre
- The Laboratory of Immunohistochemistry and Immunopathology (LIIPAT), University of Oslo, Rikshospitalet, Oslo, Norway
| | | | | | | |
Collapse
|
40
|
Harris SL, Dagtas AS, Diamond B. Regulating the isotypic and idiotypic profile of an anti-PC antibody response: lessons from peptide mimics. Mol Immunol 2002; 39:263-72. [PMID: 12220885 DOI: 10.1016/s0161-5890(02)00116-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Protection against microbial invasion depends not only on the host's ability to mount an immune response, but on its ability to mount the correct immune response. Whether an antibody response is protective or not depends on both the fine antigenic specificity, that may be associated with particular idiotypes and epitope binding characteristics, and the isotype, determining antibody effector function. Thus, both the variable and the constant region of the antibodies induced by a peptide mimotope must be considered when assessing the success of any immunization. Phosphorylcholine (PC), an epitope present on the cell-wall C-polysaccharide of all pneumococcal serotypes, is capable of eliciting a protective antibody response to pneumococcal infection in mice and provides an attractive model system for understanding the immune response generated by peptide mimics. In this system, both the idiotype and isotype of protective antibodies have been determined and the characteristics of the in vivo response are well described and highly reproducible. We describe here the immune response generated by two peptide mimics of PC. Mice immunized with the peptides developed antibodies binding PC and C-polysaccharide. The idiotypic profile of the response differed depending on the peptide, but never included canonical T15(+) antibodies. The isotype of the response to peptide mimics differed depending on a combination of peptide and adjuvant, and included both IgG2a and IgG2b antibodies which are not typically seen in the response to PC. Thus, peptide mimotopes may elicit anti-polysaccharide responses, but fail to elicit the idiotypes and isotypes observed in the protective response to the microbial antigen.
Collapse
Affiliation(s)
- Shannon L Harris
- Department of Microbiology & Immunology and Medicine, Albert Einstein College of Medicine, Room 405 Forchheimer, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | | | | |
Collapse
|
41
|
Mold C, Rodic-Polic B, Du Clos TW. Protection from Streptococcus pneumoniae infection by C-reactive protein and natural antibody requires complement but not Fc gamma receptors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:6375-81. [PMID: 12055255 DOI: 10.4049/jimmunol.168.12.6375] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Streptococcus pneumoniae is an important human pathogen and the most common cause of community-acquired pneumonia. Both adaptive and innate immune mechanisms provide protection from infection. Innate immunity to S. pneumoniae in mice is mediated by naturally occurring anti-phosphocholine (PC) Abs and complement. The human acute-phase reactant C-reactive protein (CRP) also protects mice from lethal S. pneumoniae infection. CRP and anti-PC Ab share the ability to bind to PC on the cell wall C-polysaccharide of S. pneumoniae and to activate complement. CRP and IgG anti-PC also bind to Fc gamma R. In this study, Fc gamma R- and complement-deficient mice were used to compare the mechanisms of protection conferred by CRP and anti-PC Ab. Injection of CRP protected wild-type, FcR gamma-chain-, Fc gamma RIIb-, and Fc gamma RIII-deficient mice from infection. Complement was required for the protective effect of CRP as cobra venom factor treatment eliminated the effect of CRP in both gamma-chain-deficient and wild-type mice, and CRP failed to protect C3- or C4-deficient mice from infection. Unexpectedly, gamma-chain-deficient mice were extremely sensitive to pneumococcal infection. This sensitivity was associated with low levels of natural anti-PC Ab. Gamma-chain-deficient mice immunized with nonencapsulated S. pneumoniae produced both IgM- and IgG PC-specific Abs, were protected from infection, and were able to clear the bacteria from the bloodstream. The protection provided by immunization was eliminated by complement depletion. The results show that in this model of systemic infection with highly virulent S. pneumoniae, protection from lethality by CRP and anti-PC Abs requires complement, but not Fc gamma R.
Collapse
MESH Headings
- Animals
- Antibodies, Bacterial/biosynthesis
- Antibodies, Bacterial/physiology
- C-Reactive Protein/administration & dosage
- C-Reactive Protein/therapeutic use
- Complement Pathway, Classical/genetics
- Complement Pathway, Classical/immunology
- Complement System Proteins/physiology
- Female
- Genetic Predisposition to Disease
- Humans
- Immunity, Innate/genetics
- Immunoglobulin M/biosynthesis
- Immunoglobulin M/physiology
- Injections, Intravenous
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphorylcholine/administration & dosage
- Phosphorylcholine/immunology
- Pneumococcal Infections/genetics
- Pneumococcal Infections/immunology
- Pneumococcal Infections/prevention & control
- Polysaccharides, Bacterial/administration & dosage
- Polysaccharides, Bacterial/immunology
- Receptors, IgG/deficiency
- Receptors, IgG/genetics
- Receptors, IgG/physiology
Collapse
Affiliation(s)
- Carolyn Mold
- Department of Molecular Genetics and Microbiology, School of Medicine, University of New Mexico, Albuquerque, NM 87108, USA
| | | | | |
Collapse
|
42
|
Reitan SK, Hannestad K. Immunoglobulin heavy chain constant regions regulate immunity and tolerance to idiotypes of antibody variable regions. Proc Natl Acad Sci U S A 2002; 99:7588-93. [PMID: 12032327 PMCID: PMC124293 DOI: 10.1073/pnas.052150899] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Particular syngeneic adjuvant-free monoclonal antibodies are immunogenic and elicit antibody responses against the variable region idiotypes (Ids). We here study how heavy-chain constant regions (C(H)) regulate immune responses to Ids of free, uncomplexed monoclonal antibodies. To this end, we selected two hybridomas, called Id(3) and Id(A.01), that produce immunogenic IgM(lambda)2 directed toward 2,4,6-trinitrophenyl, and subcloned rare IgG1, IgG3, IgE, or IgA class switch variants. The purified switch variants, which possessed the Ids of their IgM progenitors, were injected repeatedly without added adjuvant into BALB/c mice, and anti-Id IgG responses were determined. These repeated injections revealed that the immunogenicity of Ids was lost by switching to IgG1 and IgG3, restored when the Fc piece of IgG1 was removed, maintained by switching to IgE and monomeric IgA, and lost in polymeric IgA. Loss of immunogenicity was associated with acquisition of Id-specific tolerogenicity, as determined by immunization challenge with Id borne by IgM. An Id borne by IgG induced tolerance when injected at least 90 days before or 3-21 days after immunization with IgM Id was begun. Ids of IgG were also tolerogenic in mice deficient in Fc(gamma)RIIB or Fc(gamma)RI + III. The results suggest that Ids that have switched to IgG and pIgA negatively control immune responses to shared Ids, including the Ids of their IgM progenitors.
Collapse
Affiliation(s)
- Solveig Klaebo Reitan
- Department of Immunology, Institute of Medical Biology, School of Medicine, University of Tromsø, N-9037 Tromsø, Norway
| | | |
Collapse
|
43
|
Shapiro S, Beenhouwer DO, Feldmesser M, Taborda C, Carroll MC, Casadevall A, Scharff MD. Immunoglobulin G monoclonal antibodies to Cryptococcus neoformans protect mice deficient in complement component C3. Infect Immun 2002; 70:2598-604. [PMID: 11953401 PMCID: PMC127925 DOI: 10.1128/iai.70.5.2598-2604.2002] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Passive administration of monoclonal antibodies (MAbs) to the capsular polysaccharide of Cryptococcus neoformans can alter the course of infection in mice. In a murine model of cryptococcal infection, immunoglobulin G1 (IgG1), IgG2a, and IgG2b switch variants of the anti-capsular 3E5 MAb prolong the survival of lethally infected mice, whereas the 3E5 IgG3 MAb does not protect and in some cases enhances infection, shortening the life spans of infected mice. We examined the role of complement component C3 in Ab-mediated protection by determining the efficacy of the four mouse IgG subclasses against C. neoformans in mice genetically deficient in factor C3 as well as mice acutely depleted of C3. Similar to other complement-deficient animal models, C3(-/-) mice and mice depleted of C3 by cobra venom factor were more susceptible to C. neoformans infection than control mice, providing further evidence that complement is important in the host defense against the fungus. In the absence of C3, all IgG isotypes prolonged the lives of mice infected with C. neoformans, indicating that protection by IgG does not require the complement pathways. Furthermore, we observed protection with IgG3 in the complement-deficient mice, suggesting that complement is involved in the lack of protection observed with IgG3 in other mouse models.
Collapse
Affiliation(s)
- Scott Shapiro
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | | | | | |
Collapse
|
44
|
Azeredo da Silveira S, Kikuchi S, Fossati-Jimack L, Moll T, Saito T, Verbeek JS, Botto M, Walport MJ, Carroll M, Izui S. Complement activation selectively potentiates the pathogenicity of the IgG2b and IgG3 isotypes of a high affinity anti-erythrocyte autoantibody. J Exp Med 2002; 195:665-72. [PMID: 11901193 PMCID: PMC2193744 DOI: 10.1084/jem.20012024] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
By generating four IgG isotype-switch variants of the high affinity 34-3C anti-erythrocyte autoantibody, and comparing them to the IgG variants of the low affinity 4C8 anti-erythrocyte autoantibody that we have previously studied, we evaluated in this study how high affinity binding to erythrocytes influences the pathogenicity of each IgG isotype in relation to the respective contributions of Fcgamma receptor (FcgammaR) and complement. The 34-3C autoantibody opsonizing extensively circulating erythrocytes efficiently activated complement in vivo (IgG2a = IgG2b > IgG3), except for the IgG1 isotype, while the 4C8 IgG autoantibody failed to activate complement. The pathogenicity of the 34-3C autoantibody of IgG2b and IgG3 isotypes was dramatically higher (>200-fold) than that of the corresponding isotypes of the 4C8 antibody. This enhanced activity was highly (IgG2b) or totally (IgG3) dependent on complement. In contrast, erythrocyte-binding affinities only played a minor role in in vivo hemolytic activities of the IgG1 and IgG2a isotypes of 34-3C and 4C8 antibodies, where complement was not or only partially involved, respectively. The remarkably different capacities of four different IgG isotypes of low and high affinity anti-erythrocyte autoantibodies to activate FcgammaR-bearing effector cells and complement in vivo demonstrate the role of autoantibody affinity maturation and of IgG isotype switching in autoantibody-mediated pathology.
Collapse
|
45
|
Gamberale R, Geffner JR, Giordano M. Immune complexes and apoptosis in B-cell chronic lymphocytic leukemia. Leuk Lymphoma 2002; 43:251-5. [PMID: 11999554 DOI: 10.1080/10428190290006008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The progressive accumulation of B-cell chronic lymphocytic leukemia (B-CLL) cells in vivo is attributed to resistance to apoptosis, although this can be modulated in vitro by a variety of cellular and humoral factors (cell-cell, cell-matrix interactions, cytokines). We have previously reported that IgG immune complexes (IC) delay B-CLL cell apoptosis through a paracrine mechanism, which depends on monocytes and NK cells. On the other hand, despite the fact that IC effectively bind to type II Fc gammaRs expressed on B-CLL cells, they are unable to deliver transmembrane signals. We speculate that this lack of responsiveness of resting B-CLL cells to IC could be overcome by activation. The analysis of this possibility would be relevant since the presence of circulating IC is a common feature in B-CLL patients.
Collapse
Affiliation(s)
- Romina Gamberale
- Laboratorio de Immunologia, Instituto de Investigaciones Hematológicas, Academia de Medicina, Buenos Aires, Argentina
| | | | | |
Collapse
|
46
|
Izui S, Fossati-Jimack L, da Silveira SA, Moll T. Isotype-dependent pathogenicity of autoantibodies: analysis in experimental autoimmune hemolytic anemia. SPRINGER SEMINARS IN IMMUNOPATHOLOGY 2001; 23:433-45. [PMID: 11826619 DOI: 10.1007/s281-001-8169-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- S Izui
- Department of Pathology, University of Geneva, 1211 Geneva 4, Switzerland
| | | | | | | |
Collapse
|
47
|
Casadevall A, Pirofski LA. Adjunctive immune therapy for fungal infections. Clin Infect Dis 2001; 33:1048-56. [PMID: 11528579 DOI: 10.1086/322710] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2001] [Revised: 05/15/2001] [Indexed: 11/03/2022] Open
Abstract
Fungal infections in immunocompromised patients can pose difficult problems in clinical management, because the available antifungal chemotherapy is often unable to eradicate the infection in these people. Hence, the use of immune modulating therapy to augment impaired host immune responses--and thus enhance the efficacy of antifungal drugs--is a reasonable approach to improve the prognosis of fungal infections. Advances in biotechnology have produced a variety of biological response modifiers with the potential to serve as adjunctive immune therapy for the treatment of fungal infections, including cytokines, monoclonal antibodies, and cell growth factors. In recent years, immune-modulating therapies have been studied in an effort to define their potential use for the treatment of fungal infections. Much of the available information on the use of this approach is encouraging and invites further investigation--with the caveats that the information is mostly anecdotal and that immune-modulating therapy occasionally has produced adverse effects.
Collapse
Affiliation(s)
- A Casadevall
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| | | |
Collapse
|
48
|
Beenhouwer DO, Shapiro S, Feldmesser M, Casadevall A, Scharff MD. Both Th1 and Th2 cytokines affect the ability of monoclonal antibodies to protect mice against Cryptococcus neoformans. Infect Immun 2001; 69:6445-55. [PMID: 11553589 PMCID: PMC98780 DOI: 10.1128/iai.69.10.6445-6455.2001] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Variable-region-identical mouse immunoglobulin G1 (IgG1), IgG2b, and IgG2a monoclonal antibodies to the capsular polysaccharide of Cryptococcus neoformans prolong the lives of mice infected with this fungus, while IgG3 is either not protective or enhances infection. CD4+ T cells are required for IgG1-mediated protection, and CD8+ T cells are required for IgG3-mediated enhancement. Gamma interferon is required for both effects. These findings revealed that T cells and cytokines play a role in the modulation of cryptococcal infection by antibodies and suggested that it was important to more fully define the cytokine requirements of each of the antibody isotypes. We therefore investigated the efficacy of passively administered variable-region-identical IgG1, IgG2a, IgG2b, and IgG3 monoclonal antibodies against intravenous infection with C. neoformans in mice genetically deficient in interleukin-12 (IL-12), IL-6, IL-4, or IL-10, as well as in the parental C57BL/6J strain. The relative inherent susceptibilities of these mouse strains to C. neoformans were as follows: IL-12(-/-) > IL-6(-/-) > C57BL/6J approximately IL-4(-/-) >> IL-10(-/-). This is consistent with the notion that a Th1 response is necessary for natural immunity against cryptococcal infection. However, none of the IgG isotypes prolonged survival in IL-12(-/-), IL-6(-/-), or IL-4(-/-) mice, and all isotypes significantly enhanced infection in IL-10(-/-) mice. These results indicate that passive antibody-mediated protection against C. neoformans requires both Th1- and Th2-associated cytokines and reveal the complexity of the mechanisms through which antibodies modulate infection with this organism.
Collapse
MESH Headings
- Animals
- Antibodies, Fungal/administration & dosage
- Antibodies, Fungal/immunology
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/immunology
- Antigens, Fungal/immunology
- Cells, Cultured
- Cryptococcosis/immunology
- Cryptococcosis/mortality
- Cryptococcosis/pathology
- Cryptococcosis/prevention & control
- Cryptococcus neoformans/growth & development
- Cryptococcus neoformans/immunology
- Disease Models, Animal
- Disease Susceptibility/immunology
- Female
- Immunization, Passive/methods
- Immunoglobulin G/immunology
- Immunoglobulin Isotypes/immunology
- Interleukin-10/genetics
- Interleukin-10/immunology
- Interleukin-12/genetics
- Interleukin-12/immunology
- Interleukin-4/genetics
- Interleukin-4/immunology
- Interleukin-6/genetics
- Interleukin-6/immunology
- Macrophages, Peritoneal/cytology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/microbiology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phagocytosis/immunology
- Polysaccharides/immunology
- Th1 Cells/immunology
- Th2 Cells/immunology
Collapse
Affiliation(s)
- D O Beenhouwer
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | |
Collapse
|
49
|
Abstract
Since the description of the first mouse knockout for an IgG Fc receptor seven years ago, considerable progress has been made in defining the in vivo functions of these receptors in diverse biological systems. The role of activating Fc gamma Rs in providing a critical link between ligands and effector cells in type II and type III inflammation is now well established and has led to a fundamental revision of the significance of these receptors in initiating cellular responses in host defense, in determining the efficacy of therapeutic antibodies, and in pathological autoimmune conditions. Considerable progress has been made in the last two years on the in vivo regulation of these responses, through the appreciation of the importance of balancing activation responses with inhibitory signaling. The inhibitory FcR functions in the maintenance of peripheral tolerance, in regulating the threshold of activation responses, and ultimately in terminating IgG mediated effector stimulation. The consequences of deleting the inhibitory arm of this system are thus manifested in both the afferent and efferent immune responses. The hyperresponsive state that results leads to greatly magnified effector responses by cytotoxic antibodies and immune complexes and can culminate in autoimmunity and autoimmune disease when modified by environmental or genetic factors. Fc gamma Rs offer a paradigm for the biological significance of balancing activation and inhibitory signaling in the expanding family of activation/inhibitory receptor pairs found in the immune system.
Collapse
Affiliation(s)
- J V Ravetch
- Laboratory of Molecular Genetics and Immunology, Rockefeller University, 1230 York Ave, New York, NY 10021, USA.
| | | |
Collapse
|
50
|
Abstract
Plant diseases are a major threat to the world food supply, as up to 15% of production is lost to pathogens. In the past, disease control and the generation of resistant plant lines protected against viral, bacterial or fungal pathogens, was achieved using conventional breeding based on crossings, mutant screenings and backcrossing. Many approaches in this field have failed or the resistance obtained has been rapidly broken by the pathogens. Recent advances in molecular biotechnology have made it possible to obtain and to modify genes that are useful for generating disease resistant crops. Several strategies, including expression of pathogen-derived sequences or anti-pathogenic agents, have been developed to engineer improved pathogen resistance in transgenic plants. Antibody-based resistance is a novel strategy for generating transgenic plants resistant to pathogens. Decades ago it was shown that polyclonal and monoclonal antibodies can neutralize viruses, bacteria and selected fungi. This approach has been improved recently by the development of recombinant antibodies (rAbs). Crop resistance can be engineered by the expression of pathogen-specific antibodies, antibody fragments or antibody fusion proteins. The advantages of this approach are that rAbs can be engineered against almost any target molecule, and it has been demonstrated that expression of functional pathogen-specific rAbs in plants confers effective pathogen protection. The efficacy of antibody-based resistance was first shown for plant viruses and its application to other plant pathogens is becoming more established. However, successful use of antibodies to generate plant pathogen resistance relies on appropriate target selection, careful antibody design, efficient antibody expression, stability and targeting to appropriate cellular compartments.
Collapse
Affiliation(s)
- S Schillberg
- FraunhoferAbteilung für Molekulare Biotechnologie, IUCT, Grafschaft, Schmallenberg, Germany.
| | | | | | | |
Collapse
|