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Flajnik MF. The Janus (dual) model of immunoglobulin isotype evolution: Conservation and plasticity are the defining paradigms. Immunol Rev 2024. [PMID: 39223989 DOI: 10.1111/imr.13389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The study of antibodies in jawed vertebrates (gnathostomes) provides every immunologist with a bird's eye view of how human immunoglobulins (Igs) came into existence and subsequently evolved into their present forms. It is a fascinating Darwinian history of conservation on the one hand and flexibility on the other, exemplified by the Ig heavy chain (H) isotypes IgM and IgD/W, respectively. The cartilaginous fish (e.g., sharks) Igs provide a glimpse of "how everything got off the ground," while the amphibians (e.g., the model Xenopus) reveal how the adaptive immune system made an about face with the emergence of Ig isotype switching and IgG-like structure/function. The evolution of mucosal Igs is a captivating account of malleability, convergence, and conservation, and a call to arms for future study! In between there are spellbinding chronicles of antibody evolution in each class of vertebrates and rather incredible stories of how antibodies can adapt to occupy niches, for example, single-domain variable regions, cold-adapted Igs, convergent mechanisms to dampen antibody function, provision of mucosal defense, and many more. The purpose here is not to provide an encyclopedic examination of antibody evolution, but rather to hit the high points and entice readers to appreciate how things "came to be."
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Affiliation(s)
- Martin F Flajnik
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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2
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Hossainey MRH, Hauser KA, Garvey CN, Kalia N, Garvey JM, Grayfer L. A perspective into the relationships between amphibian ( Xenopus laevis) myeloid cell subsets. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220124. [PMID: 37305910 PMCID: PMC10258660 DOI: 10.1098/rstb.2022.0124] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/12/2022] [Indexed: 06/13/2023] Open
Abstract
Macrophage (Mϕ)-lineage cells are integral to the immune defences of all vertebrates, including amphibians. Across vertebrates, Mϕ differentiation and functionality depend on activation of the colony stimulating factor-1 (CSF1) receptor by CSF1 and interluekin-34 (IL34) cytokines. Our findings to date indicate that amphibian (Xenopus laevis) Mϕs differentiated with CSF1 and IL34 are morphologically, transcriptionally and functionally distinct. Notably, mammalian Mϕs share common progenitor population(s) with dendritic cells (DCs), which rely on fms-like tyrosine kinase 3 ligand (FLT3L) for differentiation while X. laevis IL34-Mϕs exhibit many features attributed to mammalian DCs. Presently, we compared X. laevis CSF1- and IL34-Mϕs with FLT3L-derived X. laevis DCs. Our transcriptional and functional analyses indicated that indeed the frog IL34-Mϕs and FLT3L-DCs possessed many commonalities over CSF1-Mϕs, including transcriptional profiles and functional capacities. Compared to X. laevis CSF1-Mϕs, the IL34-Mϕs and FLT3L-DCs possess greater surface major histocompatibility complex (MHC) class I, but not MHC class II expression, were better at eliciting mixed leucocyte responses in vitro and generating in vivo re-exposure immune responses against Mycobacterium marinum. Further analyses of non-mammalian myelopoiesis akin to those described here, will grant unique perspectives into the evolutionarily retained and diverged pathways of Mϕ and DC functional differentiation. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.
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Affiliation(s)
- Muhammad Riadul Haque Hossainey
- Department of Biological Sciences, The George Washington University, 800 22nd Street Northwest, Suite 6000, Washington DC 20052, USA
| | - Kelsey A. Hauser
- Department of Biological Sciences, The George Washington University, 800 22nd Street Northwest, Suite 6000, Washington DC 20052, USA
| | - Christina N. Garvey
- Department of Biological Sciences, The George Washington University, 800 22nd Street Northwest, Suite 6000, Washington DC 20052, USA
| | - Namarta Kalia
- Department of Biological Sciences, The George Washington University, 800 22nd Street Northwest, Suite 6000, Washington DC 20052, USA
| | - Juliette M. Garvey
- Department of Biological Sciences, The George Washington University, 800 22nd Street Northwest, Suite 6000, Washington DC 20052, USA
| | - Leon Grayfer
- Department of Biological Sciences, The George Washington University, 800 22nd Street Northwest, Suite 6000, Washington DC 20052, USA
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3
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Ruiz VL, Robert J. The amphibian immune system. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220123. [PMID: 37305914 PMCID: PMC10258673 DOI: 10.1098/rstb.2022.0123] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 04/16/2023] [Indexed: 06/13/2023] Open
Abstract
Amphibians are at the forefront of bridging the evolutionary gap between mammals and more ancient, jawed vertebrates. Currently, several diseases have targeted amphibians and understanding their immune system has importance beyond their use as a research model. The immune system of the African clawed frog, Xenopus laevis, and that of mammals is well conserved. We know that several features of the adaptive and innate immune system are very similar for both, including the existence of B cells, T cells and innate-like T cells. In particular, the study of the immune system at early stages of development is benefitted by studying X. laevis tadpoles. The tadpoles mainly rely on innate immune mechanisms including pre-set or innate-like T cells until after metamorphosis. In this review we lay out what is known about the innate and adaptive immune system of X. laevis including the lymphoid organs as well as how other amphibian immune systems are similar or different. Furthermore, we will describe how the amphibian immune system responds to some viral, bacterial and fungal insults. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.
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Affiliation(s)
- Vania Lopez Ruiz
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
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McGuire CC, Robert JR. Environmental endocrine disruptors and amphibian immunity: A bridge between the thyroid hormone axis and T cell development. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 140:104617. [PMID: 36529309 PMCID: PMC9892850 DOI: 10.1016/j.dci.2022.104617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Immunity is susceptible to reprogramming by environmental chemical and endocrine signals. Notably, numerous thyroid disrupting chemicals (TDCs) have the potential to perturb immune endpoints, but data are lacking on the mechanisms by which TDCs can influence the development of the immune system. T cell immunity is particularly vulnerable to modulation by TDCs during thymic education, differentiation, and selection. The following review discusses the ways in which thyroid hormones may influence T cell development, as well as emerging TDCs with potential to impact both thyroid hormone physiology and immune outcomes. To overcome the challenges of studying TDC impacts on immune toxicological endpoints, a comparative approach using the amphibian Xenopus laevis is recommended. X. laevis are ideally suited to studying TDC impacts on immunity due to the importance of thyroid hormones for metamorphosis, and the wealth of immunological models to measure immune endpoints in both tadpoles and adult frogs.
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Affiliation(s)
- Connor C McGuire
- University of Rochester Department of Microbiology and Immunology, USA; University of Rochester Department Environmental Medicine, USA
| | - Jacques R Robert
- University of Rochester Department of Microbiology and Immunology, USA; University of Rochester Department Environmental Medicine, USA.
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Humphries JE, Lanctôt CM, Robert J, McCallum HI, Newell DA, Grogan LF. Do immune system changes at metamorphosis predict vulnerability to chytridiomycosis? An update. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 136:104510. [PMID: 35985564 DOI: 10.1016/j.dci.2022.104510] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/20/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
Amphibians are among the vertebrate groups suffering great losses of biodiversity due to a variety of causes including diseases, such as chytridiomycosis (caused by the fungal pathogens Batrachochytrium dendrobatidis and B. salamandrivorans). The amphibian metamorphic period has been identified as being particularly vulnerable to chytridiomycosis, with dramatic physiological and immunological reorganisation likely contributing to this vulnerability. Here, we overview the processes behind these changes at metamorphosis and then perform a systematic literature review to capture the breadth of empirical research performed over the last two decades on the metamorphic immune response. We found that few studies focused specifically on the immune response during the peri-metamorphic stages of amphibian development and fewer still on the implications of their findings with respect to chytridiomycosis. We recommend future studies consider components of the immune system that are currently under-represented in the literature on amphibian metamorphosis, particularly pathogen recognition pathways. Although logistically challenging, we suggest varying the timing of exposure to Bd across metamorphosis to examine the relative importance of pathogen evasion, suppression or dysregulation of the immune system. We also suggest elucidating the underlying mechanisms of the increased susceptibility to chytridiomycosis at metamorphosis and the associated implications for population persistence. For species that overlap a distribution where Bd/Bsal are now endemic, we recommend a greater focus on management strategies that consider the important peri-metamorphic period.
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Affiliation(s)
- Josephine E Humphries
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia; Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, 2480, Australia.
| | - Chantal M Lanctôt
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Australian Rivers Institute, Griffith University, Southport, Queensland, 4222, Australia
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, 14642, Rochester, NY, United States
| | - Hamish I McCallum
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia
| | - David A Newell
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, 2480, Australia
| | - Laura F Grogan
- School of Environment and Science, Griffith University, Southport, Queensland, 4222, Australia; Centre for Planetary Health and Food Security, Griffith University, Southport, Queensland, 4222, Australia
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Cell landscape of larval and adult Xenopus laevis at single-cell resolution. Nat Commun 2022; 13:4306. [PMID: 35879314 PMCID: PMC9314398 DOI: 10.1038/s41467-022-31949-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 07/12/2022] [Indexed: 11/09/2022] Open
Abstract
The rapid development of high-throughput single-cell RNA sequencing technology offers a good opportunity to dissect cell heterogeneity of animals. A large number of organism-wide single-cell atlases have been constructed for vertebrates such as Homo sapiens, Macaca fascicularis, Mus musculus and Danio rerio. However, an intermediate taxon that links mammals to vertebrates of more ancient origin is still lacking. Here, we construct the first Xenopus cell landscape to date, including larval and adult organs. Common cell lineage-specific transcription factors have been identified in vertebrates, including fish, amphibians and mammals. The comparison of larval and adult erythrocytes identifies stage-specific hemoglobin subtypes, as well as a common type of cluster containing both larval and adult hemoglobin, mainly at NF59. In addition, cell lineages originating from all three layers exhibits both antigen processing and presentation during metamorphosis, indicating a common regulatory mechanism during metamorphosis. Overall, our study provides a large-scale resource for research on Xenopus metamorphosis and adult organs.
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Harly C, Robert J, Legoux F, Lantz O. γδ T, NKT, and MAIT Cells During Evolution: Redundancy or Specialized Functions? JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:217-225. [PMID: 35821101 PMCID: PMC7613099 DOI: 10.4049/jimmunol.2200105] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/06/2022] [Indexed: 01/17/2023]
Abstract
Innate-like T cells display characteristics of both innate lymphoid cells (ILCs) and mainstream αβ T cells, leading to overlapping functions of innate-like T cells with both subsets. In this review, we show that although innate-like T cells are probably present in all vertebrates, their main characteristics are much better known in amphibians and mammals. Innate-like T cells encompass both γδ and αβ T cells. In mammals, γδ TCRs likely coevolved with molecules of the butyrophilin family they interact with, whereas the semi-invariant TCRs of iNKT and mucosal-associated invariant T cells are evolutionarily locked with their restricting MH1b molecules, CD1d and MR1, respectively. The strong conservation of the Ag recognition systems of innate-like T cell subsets despite similar effector potentialities supports that each one fulfills nonredundant roles related to their Ag specificity.
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Affiliation(s)
- Christelle Harly
- Nantes Université, Institut National de la Santé et de la Recherche Médicale UMR1307, Centre National de la Recherche Scientifique UMR6075, Université d'Angers, Centre de Recherche en Cancérologie et Immunologie Intégrée Nantes Angers CRCI2NA, Nantes, France;
- LabEx Immunotherapy, Graft, Oncology, Nantes, France
| | - Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY
| | - Francois Legoux
- INSERM U932, Paris Sciences et Lettres Université, Institut Curie, Paris, France
| | - Olivier Lantz
- INSERM U932, Paris Sciences et Lettres Université, Institut Curie, Paris, France;
- Laboratoire d'Immunologie Clinique, Institut Curie, Paris, France; and
- Centre d'Investigation Clinique en Biothérapie Gustave-Roussy Institut Curie (CIC-BT1428), Paris, France
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8
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Nunes C, Koyama T, Sucena É. Co-option of immune effectors by the hormonal signalling system triggering metamorphosis in Drosophila melanogaster. PLoS Genet 2021; 17:e1009916. [PMID: 34843450 PMCID: PMC8659296 DOI: 10.1371/journal.pgen.1009916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/09/2021] [Accepted: 10/29/2021] [Indexed: 11/24/2022] Open
Abstract
Insect metamorphosis is triggered by the production, secretion and degradation of 20-hydroxyecdysone (ecdysone). In addition to its role in developmental regulation, increasing evidence suggests that ecdysone is involved in innate immunity processes, such as phagocytosis and the induction of antimicrobial peptide (AMP) production. AMP regulation includes systemic responses as well as local responses at surface epithelia that contact with the external environment. At pupariation, Drosophila melanogaster increases dramatically the expression of three AMP genes, drosomycin (drs), drosomycin-like 2 (drsl2) and drosomycin-like 5 (drsl5). We show that the systemic action of drs at pupariation is dependent on ecdysone signalling in the fat body and operates via the ecdysone downstream target, Broad. In parallel, ecdysone also regulates local responses, specifically through the activation of drsl2 expression in the gut. Finally, we confirm the relevance of this ecdysone dependent AMP expression for the control of bacterial load by showing that flies lacking drs expression in the fat body have higher bacterial persistence over metamorphosis. In contrast, local responses may be redundant with the systemic effect of drs since reduction of ecdysone signalling or of drsl2 expression has no measurable negative effect on bacterial load control in the pupa. Together, our data emphasize the importance of the association between ecdysone signalling and immunity using in vivo studies and establish a new role for ecdysone at pupariation, which impacts developmental success by regulating the immune system in a stage-dependent manner. We speculate that this co-option of immune effectors by the hormonal system may constitute an anticipatory mechanism to control bacterial numbers in the pupa, at the core of metamorphosis evolution.
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Affiliation(s)
- Catarina Nunes
- Evolution and Development Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Takashi Koyama
- Section for Cell and Neurobiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Élio Sucena
- Evolution and Development Laboratory, Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Departamento de Biologia Animal, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
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9
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Didinger C, Eimes JA, Lillie M, Waldman B. Multiple major histocompatibility complex class I genes in Asian anurans: Ontogeny and phylogeny. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 70:69-79. [PMID: 28027939 DOI: 10.1016/j.dci.2016.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 06/06/2023]
Abstract
Amphibians, as the first terrestrial vertebrates, offer a window into early major histocompatibility complex (MHC) evolution. We characterized the MHC class I of two Korean amphibians, the Asiatic toad (Bufo gargarizans) and the Japanese tree frog (Hyla japonica). We found at least four transcribed MHC class I (MHC I) loci, the highest number confirmed in any anuran to date. Furthermore, we identified MHC I transcripts in terrestrial adults, and possibly in aquatic larvae, of both species. We conducted a phylogenetic analysis based on MHC I sequence data and found that B. gargarizans and H. japonica cluster together in the superfamily Nobleobatrachia. We further identified three supertypes shared by the two species. Our results reveal substantial variation in the number of MHC I loci in anurans and suggest that certain supertypes have particular physiochemical properties that may confer pathogen resistance.
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Affiliation(s)
- Chelsea Didinger
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - John A Eimes
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Mette Lillie
- Department of Medical Biochemistry and Microbiology (IMBIM), Genomics, Uppsala University, Box 582, 75123 Uppsala, Sweden
| | - Bruce Waldman
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
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De Jesús Andino F, Chen G, Li Z, Grayfer L, Robert J. Susceptibility of Xenopus laevis tadpoles to infection by the ranavirus Frog-Virus 3 correlates with a reduced and delayed innate immune response in comparison with adult frogs. Virology 2012; 432:435-43. [PMID: 22819836 DOI: 10.1016/j.virol.2012.07.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 06/22/2012] [Accepted: 07/01/2012] [Indexed: 01/04/2023]
Abstract
Xenopus laevis adults mount effective immune responses to ranavirus Frog Virus 3 (FV3) infections and clear the pathogen within 2-3 weeks. In contrast, most tadpoles cannot clear FV3 and succumb to infections within a month. While larval susceptibility has been attributed to ineffective adaptive immunity, the contribution of innate immune components has not been addressed. Accordingly, we performed a comprehensive gene expression analysis on FV3-infected tadpoles and adults. In comparison to adults, leukocytes and tissues of infected tadpoles exhibited modest (10-100 time lower than adult) and delayed (3 day later than adult) increase in expression of inflammation-associated (TNF-α, IL-1β and IFN-γ) and antiviral (Mx1) genes. In contrast, these genes were readily and robustly upregulated in tadpoles upon bacterial stimulation. Furthermore, greater proportions of larval than adult PLs were infected by FV3. Our study suggests that tadpole susceptibility to FV3 infection is partially due to poor virus-elicited innate immune responses.
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Affiliation(s)
- Francisco De Jesús Andino
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
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Antiviral immunity in amphibians. Viruses 2011; 3:2065-2086. [PMID: 22163335 PMCID: PMC3230842 DOI: 10.3390/v3112065] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 10/20/2011] [Accepted: 10/22/2011] [Indexed: 01/27/2023] Open
Abstract
Although a variety of virus species can infect amphibians, diseases caused by ranaviruses ([RVs]; Iridoviridae) have become prominent, and are a major concern for biodiversity, agriculture and international trade. The relatively recent and rapid increase in prevalence of RV infections, the wide range of host species infected by RVs, the variability in host resistance among population of the same species and among different developmental stages, all suggest an important involvement of the amphibian immune system. Nevertheless, the roles of the immune system in the etiology of viral diseases in amphibians are still poorly investigated. We review here the current knowledge of antiviral immunity in amphibians, focusing on model species such as the frog Xenopus and the salamander (Ambystoma tigrinum), and on recent progress in generating tools to better understand how host immune defenses control RV infections, pathogenicity, and transmission.
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Robert J, Cohen N. The genus Xenopus as a multispecies model for evolutionary and comparative immunobiology of the 21st century. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:916-923. [PMID: 21277325 PMCID: PMC3109137 DOI: 10.1016/j.dci.2011.01.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Xenopus model for immunological research offers a collection of invaluable research tools including MHC-defined clones, inbred strains, cell lines, and monoclonal antibodies. Further, the annotated full genome sequence of Xenopus tropicalis and its remarkable conservation of gene organization with mammals, as well as ongoing genome mapping and mutagenesis studies in X. tropicalis, add a new dimension to the study of immunity. In this paper, we review uses of this amphibian model to study: the development of the immune system; vascular and lymphatic regeneration; immune tolerance; tumor immunity; immune responses to important emerging infectious diseases; and the evolution of classical and non-classical MHC class I genes. We also discuss the rich potential of the species with different degrees of polypoidy resulting from whole genome-wide duplication of the Xenopodinae subfamily as a model to study regulation at the genome level.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States.
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14
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Abstract
Xenopus laevis is the model of choice for evolutionary, comparative, and developmental studies of immunity, and invaluable research tools including MHC-defined clones, inbred strains, cell lines, and monoclonal antibodies are available for these studies. Recent efforts to use Silurana (Xenopus) tropicalis for genetic analyses have led to the sequencing of the whole genome. Ongoing genome mapping and mutagenesis studies will provide a new dimension to the study of immunity. Here we review what is known about the immune system of X. laevis integrated with available genomic information from S. tropicalis. This review provides compelling evidence for the high degree of similarity and evolutionary conservation between Xenopus and mammalian immune systems. We propose to build a powerful and innovative comparative biomedical model based on modern genetic technologies that takes take advantage of X. laevis and S. tropicalis, as well as the whole Xenopus genus. Developmental Dynamics 238:1249-1270, 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA.
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IgD, like IgM, is a primordial immunoglobulin class perpetuated in most jawed vertebrates. Proc Natl Acad Sci U S A 2006; 103:10723-8. [PMID: 16818885 DOI: 10.1073/pnas.0601407103] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
IgD has remained a mysterious Ig class and a bane to immunology students since its discovery >40 years ago. Its spotty occurrence in mammals and birds and the discovery of an isotype with similarities to IgD in bony fish are perplexing. We have identified IgD heavy (H) chain (delta) from the amphibian Xenopus tropicalis during examination of the IgH locus. The Xenopus delta gene is in the same position, immediately 3' of the IgM gene, as in mammals, and it is expressed only in the spleen at low levels, primarily as a transmembrane receptor by surface IgM(+) cells. Our data suggest that frog IgD is expressed on mature B cells, like in mouse/human. Unexpectedly, Xenopus IgD is orthologous to IgW, an Ig isotype found only in cartilaginous fish and lungfish, demonstrating that IgD/W, like IgM, was present in the ancestor of all living jawed vertebrates. In striking contrast to IgM, IgD/W is evolutionarily labile, showing many duplications/deletions of domains, the presence of multiple splice forms, existence as predominantly a secretory or transmembrane form, or loss of the entire gene in a species-specific manner. Our study suggests that IgD/W has played varied roles in different vertebrate taxa since the inception of the adaptive immune system, and it may have been preserved as a flexible locus over evolutionary time to complement steadfast IgM.
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Gantress J, Maniero GD, Cohen N, Robert J. Development and characterization of a model system to study amphibian immune responses to iridoviruses. Virology 2003; 311:254-62. [PMID: 12842616 DOI: 10.1016/s0042-6822(03)00151-x] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The recent realization that viruses within the family Iridoviridae may contribute to the worldwide decline in amphibians makes it urgent to understand amphibian antiviral immune defenses. We present evidence that establishes the frog Xenopus laevis as an important model with which to study anti-iridovirus immunity. Adults resist high doses of FV3 infection, showing only transitory signs of pathology. By contrast, naturally MHC class-I-deficient tadpoles are highly susceptible to FV3 infection. Monitoring of viral DNA by PCR indicates a preferential localization of FV3 DNA in the kidney, with the inbred MHC homozygous J strain appearing to be more susceptible. Clearance of virus as measured by detection of FV3 DNA and also the disappearance of pathological and behavioral symptoms of infection, acceleration of viral clearance, and detection of IgY anti-FV3 antibodies after a second injection of FV3 are all consistent with the involvement of both cellular and humoral adaptive antiviral immune responses.
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Affiliation(s)
- Jennifer Gantress
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA
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Fischer U, Utke K, Ototake M, Dijkstra JM, Köllner B. Adaptive cell-mediated cytotoxicity against allogeneic targets by CD8-positive lymphocytes of rainbow trout (Oncorhynchus mykiss). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2003; 27:323-337. [PMID: 12590966 DOI: 10.1016/s0145-305x(02)00100-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Rainbow trout surface-(s)IgM(-) leukocytes exhibited cell-mediated cytotoxicity (CMC) against allogeneic cells. This is described in concordance with a characterization of gene expression in the effector cells. Peripheral blood leukocytes (PBL) isolated from trout grafted with allogeneic tissue lysed allogeneic target cells (erythrocytes or cells of the RTG-2 cell line) in in vitro assays. The PBL were magnetically separated into different subpopulations using monoclonal antibodies (mabs) specific to thrombocytes, IgM, granulocytes and monocytes. Of the isolated subpopulations only the sIgM(-) lymphocytes were capable of lysing allogeneic targets. The separated PBL fractions were characterized by RT-PCR analysis using specific primers for the amplification of trout IgM heavy chain constant region (CH1), T cell receptor alpha chain (TCRalpha), CD8alpha and major histocompatibility complex (MHC) class I gene fragments. Most importantly, CD8alpha was expressed only by the sIgM(-) population. Combined with the requirement for sensitization to detect CMC, this strongly suggests T cell involvement in fish as in higher vertebrates. The involvement of CD8alpha-positive cytotoxic T cells in allograft rejection was supported by additional in vivo and in vitro observations. CD8alpha expression was barely detectable in the blood of unsensitized trout or trout that received xenografts, but was easily detected in the blood of allogeneically stimulated trout. Furthermore, CD8alpha expression in sIgM(-) lymphocytes from immunized trout was secondarily enhanced by addition of allogeneic targets in vitro. Collectively, these functional and genetic data suggest that fish possess specific cytotoxic cells with phenotype and gene expression pattern similar to those of cytotoxic T cells in higher vertebrates.
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Affiliation(s)
- Uwe Fischer
- Institute of Infectiology, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, Insel Riems, Germany.
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18
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Dijkstra JM, Köllner B, Aoyagi K, Sawamoto Y, Kuroda A, Ototake M, Nakanishi T, Fischer U. The rainbow trout classical MHC class I molecule Onmy-UBA*501 is expressed in similar cell types as mammalian classical MHC class I molecules. FISH & SHELLFISH IMMUNOLOGY 2003; 14:1-23. [PMID: 12547623 DOI: 10.1006/fsim.2001.0407] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Onmy-UBA is a polymorphic classical major histocompatibility (MHC) class I locus in rainbow trout (Oncorhynchus mykiss). A common allomorph is Onmy-UBA*501, which has been detected in several wildtype strains, in the clonal homozygous rainbow trout C25 and, in the current study, in the rainbow trout gonad cell line RTG-2. The extracellular domain of this allomorph was expressed in E. coli and a murine monoclonal antibody designated H9 was generated against the recombinant protein. In Western blot analysis Mab H9 specifically recognised an n-glycosylated protein of 45 kDa in leucocytes and erythrocytes of C25 fish and in RTG-2 cells. The level of Onmy-UBA*501 expression in erythrocytes was very low. Immunocytochemistry of isolated cells indicated expression in lymphocytes, macrophages, neutrophils, erythrocytes, RTG-2 cells and Onmy-UBA *501 transfected CHO cells, but not in untransfected CHO cells. Immunohistochemistry using frozen sections of C25 fish indicated that Onmy-UBA*501 expression is strong in the lymphoid organs (thymus, head kidney and spleen) and in the epithelia and endothelia of several organs. No significant expression was observed in muscle fibres, hepatocytes or neurons. These observations demonstrate that in jawed fish, the lowest phylogenetic group possessing an MHC system, the classical MHC class I molecules are expressed in similar cell types as in higher vertebrates.
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Affiliation(s)
- Johannes M Dijkstra
- Immunology Section, National Research Institute of Aquaculture, Tamaki Mie, 519-0423, Japan
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19
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Robert J, Sung M, Cohen N. In vitro thymocyte differentiation in MHC class I-negative Xenopus larvae. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2001; 25:323-336. [PMID: 11246072 DOI: 10.1016/s0145-305x(00)00066-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
CTX is a surface antigen whose expression in larval and adult Xenopus is primarily restricted to MHC class I-negative immature cortical thymocytes. In adult Xenopus, surface expression of CTX marks a population of MHC class I(-) CD8(+) immature thymocytes that appears to be the equivalent of the mammalian CD4CD8 double positive subset. The present study reveals that transient in vitro exposure of immature CTX(+) thymocytes from MHC class I-negative tadpoles to suboptimal mitogenic concentrations of phorbol ester (PMA) plus ionomycin, induces larval cells to differentiate into more mature T-lymphoblasts that express high level of surface CD5 and CD45. These T-lymphoblasts have downregulated CTX, Rag 1 and TdT genes, whereas TCR-beta genes remain actively transcribed. Signaling induced by PMA/ionomycin modulates both class I and class II expression of MHC class I/II-negative larval thymocytes. This study also reveals that larval T-lymphoblasts are composed of two distinct subsets: CD5(high)CD8(-) and CD5 (high)CD8 (high).
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MESH Headings
- Animals
- Animals, Outbred Strains
- Antigens, Differentiation, T-Lymphocyte
- CD5 Antigens/biosynthesis
- CD5 Antigens/genetics
- CD8 Antigens/biosynthesis
- CD8 Antigens/genetics
- Cell Differentiation/drug effects
- DNA Nucleotidylexotransferase/biosynthesis
- DNA Nucleotidylexotransferase/genetics
- Gene Expression Regulation/drug effects
- Genes, MHC Class I
- Genes, MHC Class II
- Histocompatibility Antigens Class I/analysis
- Histocompatibility Antigens Class II/biosynthesis
- Homeodomain Proteins/biosynthesis
- Homeodomain Proteins/genetics
- Immunophenotyping
- Ionomycin/pharmacology
- Larva
- Leukocyte Common Antigens/biosynthesis
- Leukocyte Common Antigens/genetics
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/drug effects
- T-Lymphocyte Subsets/immunology
- Tetradecanoylphorbol Acetate/pharmacology
- Thymus Gland/cytology
- Thymus Gland/growth & development
- Xenopus Proteins
- Xenopus laevis/growth & development
- Xenopus laevis/immunology
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Affiliation(s)
- J Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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20
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Carey C, Cohen N, Rollins-Smith L. Amphibian declines: an immunological perspective. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1999; 23:459-72. [PMID: 10512457 DOI: 10.1016/s0145-305x(99)00028-2] [Citation(s) in RCA: 264] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Many, but not all, amphibian populations have been declining on all six continents on which they live. Although habitat destruction, direct application of toxicants, and introduction of predators/competitors are obvious causes of amphibian declines, many amphibians are dying of infectious diseases in relatively pristine habitats on several continents. In this paper, we review the patterns of these disease outbreaks and the characteristics of amphibian immune systems. Hypotheses are presented to explain the apparent susceptibility of amphibians to these pathogens. Natural and man-made factors that can alter amphibian immune responses to pathogens are discussed. Additional research is needed on the biology of the specific pathogens, the pattern of immune responses they elicit, and the nature of environmental stressors that may increase susceptibility to infectious disease.
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Affiliation(s)
- C Carey
- Department of EPO Biology, University of Colorado, Boulder 80309-0334, USA.
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21
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Abstract
We have developed a novel experimental model of cancer immunity in the frog, Xenopus, which may provide a useful alternative to murine tumor models and a way to assess whether the control of tumor development is a fundamental function of the immune system of vertebrates. In Xenopus, tumor immunity can be studied in two developmentally distinct immune systems. The larval immune system reflects characteristics of an ancestral system that appears to function without classical MHC class I antigen presentation and an efficient effector mechanism. The adult system appears more highly evolved in that it is remarkably similar to that of mammals and is able to generate a potent antitumor response. This amphibian model also provides a unique system with which to investigate a postulated role of heat shock proteins as components of an ancestral system of antigen presentation and/or immune surveillance that predates the antigen presentation pathway that exclusively involves MHC molecules.
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Affiliation(s)
- J Robert
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, New York, USA.
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22
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Abstract
Studies of the ontogeny of immunity in a limited number of representative amphibians have shown that while the immune systems of the larval forms are competent to defend against potential pathogens in the temporary ponds they inhabit, they are not equivalent to the mature immune systems that develop after metamorphosis. Metamorphosis is a critical time of transition when increased concentrations of metamorphic hormones, principally thyroid hormones (TH) and corticosteroid hormones (CH), orchestrate the loss or reorganization of many tissues and organ systems, including the immune system. Immune system reorganization may serve to eliminate unnecessary lymphocytes that could be destructive if they recognized newly emerging adult-specific antigens on the adult tissues. Increased corticosteroids during metamorphosis appear to induce apoptosis of susceptible lymphocytes. This cell death can be inhibited in vitro or in vivo by the corticosteroid receptor antagonist, RU486. A coordinate increase in both TH and CH at metamorphosis may be common to all amphibians that undergo metamorphosis. Current evidence suggests that the central hypothalamic mediator that induces pituitary production of both thyroid-stimulating hormone and adrenocorticotropic hormone in larval amphibians is corticotropin-releasing hormone. Most amphibians probably survive the temporary immunosuppression associated with metamorphosis with no deleterious effects. However, it is hypothesized that if environmental stressors result in the induction of metamorphosis at a less than optimal body size and state of immune maturation, the immune system destruction would be more significant, and the amphibians could be at greater risk of infection and death.
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Affiliation(s)
- L A Rollins-Smith
- Department of Microbiology & Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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23
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Ohmura H, Wakahara M. Transformation of skin from larval to adult types in normally metamorphosing and metamorphosis-arrested salamander, Hynobius retardatus. Differentiation 1998. [DOI: 10.1046/j.1432-0436.1998.6350237.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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24
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Abstract
In Xenopus, the type I transmembrane protein, CTX (cortical thymocyte-specific antigen of Xenopus), is hypothesized to play a role in thymocyte differentiation and/or thymic selection. The present studies were undertaken to gather additional evidence in support of a postulated association of CTX with a differentiation step of a cell population that corresponds to the murine immature double positive (CD4+CD8+TCR+) thymocyte subset. During ontogeny, cell surface expression of CTX on thymocytes can first be detected by immunocytochemistry and flow cytometry at 8 days post-fertilization, about 1 day after CD8+ cells first appear. By 12 days post-fertilization, T-cells in the entire cortex except for the outer most layer of cells, are intensely CTX positive, whereas those in the medulla are negative. This pattern persists throughout larval and postmetamorphic life.
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Affiliation(s)
- J Robert
- Department of Microbiology, University of Rochester Medical Center, NY 14642, USA.
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25
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Salter-Cid L, Nonaka M, Flajnik MF. Expression of MHC Class Ia and Class Ib During Ontogeny: High Expression in Epithelia and Coregulation of Class Ia and lmp7 Genes. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.160.6.2853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The amphibian Xenopus permits the examination of immune responses in a species that progresses through two distinct lives, tadpole and adult, in which animals are free-living and immunocompetent. MHC gene expression as well as general features of the immune system change profoundly at metamorphosis. In this study gene expression of class Ia, class Ib, and the immune proteasome component lmp7 was investigated by Northern blotting at all stages of development. Class Ia genes are expressed in most adult tissues, with highest levels in intestine. Class Ib genes are expressed at lower levels, and their tissue distribution is somewhat more restricted than that of class Ia. Consistent with the idea that particular class Ib isotypes can perform distinct functions, preferential expression of class Ib genes is found in some tissues, with one family being expressed exclusively in epithelia. The onset of MHC expression is not simultaneous in all tissues: class Ia transcripts are first present in tadpole lung, gill, and intestine, organs with epithelial surfaces in contact with the environment. In every tissue except colon and muscle, class Ia expression increases markedly after metamorphosis. Interestingly, expression of the MHC-linked proteasome component lmp7 mirrored class Ia expression, while the constitutive lmp7 homologue X was expressed ubiquitously at all stages. Class Ib transcripts were never detected before metamorphosis, suggesting that the Xenopus class Ib proteins identified to date do not subserve class Ia functions in tadpole life.
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Affiliation(s)
- Luisa Salter-Cid
- *Department of Microbiology and Immunology, University of Miami, Miami, FL 33101; and
| | - Masaru Nonaka
- †Department of Biochemistry, Nagoya City University, Nagoya, Japan
| | - Martin F. Flajnik
- *Department of Microbiology and Immunology, University of Miami, Miami, FL 33101; and
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26
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Fischer U, Ototake M, Nakanishi T. In vitro cell-mediated cytotoxicity against allogeneic erythrocytes in ginbuna crucian carp and goldfish using a non-radioactive assay. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1998; 22:195-206. [PMID: 9639089 DOI: 10.1016/s0145-305x(97)00052-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Cell-mediated cytotoxicity of clonal ginbuna crucian carp leukocytes against allogeneic erythrocytes is described using a sensitive non-radioactive in vitro assay. Hemoglobin released from target erythrocytes after cell-mediated erythrolysis was detected by tetramethylbenzidine (TMB). TMB assay showed clear correlation with a 51Cr-release assay and even exhibited higher cytotoxicity. The use of erythrocytes as target cells has several advantages over a conventional 51Cr-release assay. Erythrocytes do not have cytotoxic activity, are relatively homogeneous, are available in large numbers and erythrocyte donors need not be killed. Leukocytes from fish sensitized by erythrocyte injection or scale grafting efficiently lysed allogeneic erythrocytes, but did not kill isogeneic or autologous erythrocytes. In contrast, leukocytes from unsensitized fish did not lyse allogeneic erythrocytes and repeated sensitizations by allogeneic grafts were necessary to induce cytotoxic cells. Effector cells isolated from peripheral blood showed a higher cytotoxic effect toward allogeneic target cells than effector cells isolated from kidney. These studies support the hypothesis that fish are capable of a genetically restricted specific cell-mediated cytotoxicity.
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Affiliation(s)
- U Fischer
- Institute of Applied Virology, Federal Research Centre for Virus Diseases of Animals, Friedrich-Loeffler-Institutes, Insel Riems, Germany.
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27
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Robert J, Chretien I, Guiet C, Du Pasquier L. Cross-linking CTX, a novel thymocyte-specific molecule, inhibits the growth of lymphoid tumor cells in Xenopus. Mol Immunol 1997; 34:133-43. [PMID: 9188846 DOI: 10.1016/s0161-5890(97)00006-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CTX, a new Xenopus Ig superfamily molecule present on some cortical thymocytes and lymphoid tumor cells, is expressed at the cell surface under six differently glycosylated isoforms as shown by two-dimensional gel analysis and by endo F glycosidase treatment. Following chemical cross-linking before immunoprecipitation, a large fraction of surface CTX forms non-covalently linked dimers at the cell surface. This finding, which is consistent with the presence of a J segment with diglycine beta bulge in the V region of the molecule, suggests that this dimer has the same conformation as a T-cell receptor (TCR) or an Ig molecule. The V8 digest patterns of the monomers and dimers are identical. While this suggests that the dimer is a homodimer of two CTX chains, it does not distinguish whether each CTX chain is encoded by the same or different gene loci. When tumor cells were added to culture wells that had been coated with the anti-CTX monoclonal antibody X71, 30-50% underwent rapid (within 30 min) morphological changes followed by growth inhibition as determined by a decrease in thymidine incorporation and by direct cell counting. No apoptosis, calcium flux or external calcium requirement was noted after cross-linking of CTX. These results suggest that CTX can function as a receptor, and that its interaction with a ligand influences the control of cell proliferation through a signalling pathway that is distinct from the TCR machinery.
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Affiliation(s)
- J Robert
- Basel Institute for Immunology, Switzerland
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28
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Abstract
Using class specific monoclonal antibodies we analyzed the tissue distribution of B cells expressing the three immunoglobulin (Ig) isotypes (IgM, IgX, IgY) in Xenopus. Large numbers of IgM- and IgX-, but not IgY-, positive B cells are located in the gut epithelium of the intestine. In this organ up to 60% of all B cells can be IgX positive, while in the spleen or liver they are hardly detectable. The majority of IgX-producing cells resemble plasma cells. IgY-producing cells are found in the liver and spleen but not in the intestine. In contrast to IgY, the expression of IgM and IgX is thymus independent. Upon systemic immunization, a several-fold increase of specific IgM and IgY, but not IgX, antibodies was detected in the sera. This and its association with the mucosae of the intestine resembles results reported for mammalian IgA; therefore, IgX of Xenopus might be considered an analog of IgA.
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Affiliation(s)
- R Mussmann
- Basel Institute for Immunology, Switzerland
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29
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Abstract
Programmed cell death occurs in a variety of organs during amphibian metamorphosis and is usually identified by electron microscopy as apoptosis or its modifications. Because of the massive cell death that occurs during a short period, amphibian organs serve as an ideal model system for the study of mechanisms underlying programmed cell death. In this article, a series of morphological changes in apoptosis from their nuclear changes to removal by phagocytic macrophages is reviewed, mainly in the small intestine of metamorphosing Xenopus laevis tadpoles. It is well known that cell death during amphibian metamorphosis is under the control of thyroid hormone (TH), and changes in gene expression induced by TH have been recently analyzed in a few Xenopus organs. On the other hand, there is a growing body of evidence that cell death is regulated by various kinds of local factors. For example, roles of interactions with other tissue cells and/or participation of immunocompetent cells in cell death have been experimentally shown. Therefore, to clarify the mechanisms of this complicated process, it is important at present that TH-induced changes in gene expression of each cell type comprising the organ are chronologically examined by combining morphological and molecular biological techniques.
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Affiliation(s)
- A Ishizuya-Oka
- Department of Anatomy, Dokkyo University School of Medicine, Tochigi, Japan
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30
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Robert J, Guiet C, Du Pasquier L. Ontogeny of the alloimmune response against a transplanted tumor in Xenopus laevis. Differentiation 1995; 59:135-44. [PMID: 7589897 DOI: 10.1046/j.1432-0436.1995.5930135.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Xenopus laevis lymphoid tumor cells of the ff genotype grow after transplantation in inbred ff tadpoles or young post-metamorphic animals, but do not grow in fully grown ff adults. The ability to grow is lost progressively after metamorphosis and is apparently due to an immune response of the adult host against minor histocompatibility antigens (non-MHC encoded) expressed by the tumor cells. The difference in alloimmune responses between the larval and the adult immune system of the amphibian Xenopus has been subsequently investigated with this new in vivo model. The resistance of the host against transplanted tumor cells rises during the post-metamorphic development in parallel with the second histogenesis observed in the thymus, the expression of MHC class II by peripheral T cells and the recovery of T cell effector functions such as MLR, and can be abrogated by sub-lethal irradiation. Pre-immunization of ff adults with irradiated ff-2 cells specifically accelerates subsequent ff skin graft rejection, which implies the generation of memory against antigenic determinants common between the ff skin and the tumor cells. Similarly, both anti-ff alloserum and anti-ff-2 serum contain antibodies specifically precipitating two surface proteins (180-200 kDa) from ff-2 cells. One of these proteins is also detected on normal ff thymocytes and splenic T cells. On the other hands, ff-2 tumor cells (MHC I+II-) are not rejected by class I-negative tadpoles (class I expression on the tumor cell surface is even increased), and no anti-tumor antibody response can be detected. However, tumor growth has been reduced in tadpoles following priming with irradiated ff-2 cells, although immunization is not sufficient to prevent ultimate tumor development and tadpole death. Moreover, priming with irradiated ff-2 cells at larval stages does interfere with tumor growth in transplanted young post-metamorphic adults, suggesting that long-lived memory has been generated and has been maintained through metamorphosis. These results suggest that the lack of tumor rejection by larvae results from an incomplete effector function rather than an absence of recognition. Full responsiveness against minor H antigens cannot be elicited before adulthood.
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Affiliation(s)
- J Robert
- Basel Institute for Immunology, Switzerland
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31
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Du Pasquier L, Courtet M, Robert J. A Xenopus lymphoid tumor cell line with complete Ig genes rearrangements and T-cell characteristics. Mol Immunol 1995; 32:583-93. [PMID: 7609735 DOI: 10.1016/0161-5890(95)00002-v] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The first lymphoid cell line derived from an amphibian (Xenopus) thymic tumor shows an extreme form of lineage infidelity. Although it has rearranged in-frame the two alleles of the heavy chain, deleted one light chain locus, and rearranged abortively the two alleles of the second light chain locus, the cell line does not produce immunoglobulin molecules or message. It expresses a variety of T-cell characteristic markers such as Xenopus pan T-cell markers, CD8 equivalent and GATA3 transcription factor. It does not express any major histocompatibility complex class I or class II molecules. It resembles some rare types of mammalian leukemias.
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32
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Sakuraoka J, Tochinai S. Demonstration of cells involved in rejection of tolerogenic grafts in tolerant Xenopus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 1993; 17:439-447. [PMID: 8270095 DOI: 10.1016/0145-305x(93)90035-o] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The J-strain (JJ) clawed frog, Xenopus laevis, can easily be made tolerant of semixenogeneic (X. laevis x X. borealis; JB) adult skin grafted onto larvae before stage 57 (larvally induced tolerance). To examine the cellular bases of this tolerance, we have established a simple and reliable method of quantifying the proliferating splenocytes in vivo by using BrdU and anti-BrdU antibody. When adult JJ frogs were injected with adult JB peripheral blood cells (PBCs), host splenic lymphocytes proliferated even in frogs that were tolerant of JB skin. Splenic lymphocytes from animals primed in vivo with JB PBCs were injected into early thymectomized (Txd) frogs that carried previously grafted JB skin. In Txd frogs injected with splenocytes from normal frogs, the rejection of JB skin grafts was initiated promptly and ended in about 10 days. Rejection was relatively delayed in the frogs injected with splenocytes depleted of proliferating cells, suggesting that the proliferating cells were actively involved in the rejection process. Early Txd frogs injected with splenocytes from undisturbed tolerant donors did not reject JB skin grafts. Quite unexpectedly, all five early Txd frogs, injected with undepleted splenocytes from tolerant donors previously stimulated with JB PBCs, rejected the JB skin grafts, four of them subacutely. In frogs injected with the splenocytes from PBC-injected tolerant donors that had been depleted of proliferating cells, the rejection was delayed. The most likely explanation is that cells actively involved in graft rejection exist in tolerant frogs and can be stimulated to proliferate, although cytotoxicity of the graft is usually suppressed or disabled by unknown mechanisms.
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Affiliation(s)
- J Sakuraoka
- Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan
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33
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Maeno M, Ong RC, Kung HF. Positive and Negative Regulation of the Differentiation of Ventral Mesoderm for Erythrocytes in Xenopus laevis. (Xenopus laevis/erythropoiesis/embryonic blood island/explant/regulation). Dev Growth Differ 1992. [DOI: 10.1111/j.1440-169x.1992.00567.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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Abstract
Three subpopulations of light chains in Xenopus can be distinguished by monoclonal antibodies as well as by electrophoretic mobility on SDS-PAGE, peptide map and cell surface distribution. Analysis of these proteins from LPS-stimulated lymphocytes culture supernatants by two-dimensional gel electrophoresis showed a heterogeneity comparable to that observed for mouse kappa light chains. However, evidence from the selective expression of light chain subpopulations, as well as highly restricted light chain representation in anti-DNP antibodies, supports earlier findings that an antibody response in Xenopus is greatly limited in heterogeneity.
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Affiliation(s)
- E Hsu
- Basel Institute for Immunology, Switzerland
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35
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Grossberger D, Flajnik M, Marcuz A. Ribosomal and chromosomal protein cDNA clones of Xenopus laevis thymus isolated with differential screening. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1991; 98:127-33. [PMID: 2060276 DOI: 10.1016/0305-0491(91)90318-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
1. Xenopus laevis is an excellent system for the study of the evolution and ontogeny of the immune system. But since only immunoglobulin genes have been isolated from this species, we undertook to isolate other genes expressed in an immunologically important organ, the thymus. 2. We used differential screening of a thymus cDNA library with cDNA probes made from thymus and from erythroblasts. 3. Approximately 50 clones which hybridized to the probe from thymus, but not from erythroblast, were isolated and sequenced from their termini. 4. Several clones were identified in data bank searches by their similarity to previously published sequences, and the partial sequences of these loci are reported here. 5. These include elongation factor 2, ribosomal protein S11, ribosomal protein S13, and the high mobility group protein. 6. Although these genes are not expected to be involved in an immune function, the availability of these sequences will facilitate the study of these loci in this species.
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36
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Rollins-Smith LA, Blair P. Contribution of ventral blood island mesoderm to hematopoiesis in postmetamorphic and metamorphosis-inhibited Xenopus laevis. Dev Biol 1990; 142:178-83. [PMID: 2172056 DOI: 10.1016/0012-1606(90)90161-b] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In an effort to label very early erythrocyte and lymphocyte populations and to follow their fate in normally developing postmetamorphic frogs and goitrogen-treated permanent larvae, diploid (2N) and triploid (3N) ventral blood island (VBI) mesoderm was exchanged between neurula stage embryos (about 16-22 hr old). Beginning at 15 days of age, half of the 2N or 3N hosts were treated with sodium perchlorate to prevent thyroxine-induced developmental changes. At larval stages 55-59 (41-48 days) and at 1-2 months postmetamorphosis (110-120 days), the untreated control chimeras and age-matched perchlorate-treated chimeras were killed for analysis of the VBI contribution to blood, spleen, and thymus populations by flow cytometry. The data suggest that grafting of ventral blood island mesoderm is an effective way to label an early larval erythrocyte population that declines after metamorphosis. In perchlorate-blocked permanent larvae this early VBI-derived erythrocyte population persists. In contrast, grafting of VBI mesoderm was less useful as a method to label a larvally distinct lymphocyte population in the thymus and spleen. At the late larval stages that we examined, the proportion of VBI-derived cells in thymus and spleen was not different from that observed after metamorphosis. Inhibition of metamorphosis interfered with the thymocyte expansion that normally occurs after metamorphosis, but the proportion of VBI-derived cells in thymus and spleen was not affected. This suggests that lymphopoiesis occurring in late larval life and after metamorphosis uses a stable persisting population of VBI-derived stem cells as well as dorsally derived stem cells.
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Affiliation(s)
- L A Rollins-Smith
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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Flajnik MF, Ferrone S, Cohen N, Du Pasquier L. Evolution of the MHC: antigenicity and unusual tissue distribution of Xenopus (frog) class II molecules. Mol Immunol 1990; 27:451-62. [PMID: 2366760 DOI: 10.1016/0161-5890(90)90170-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Antibodies that recognize Xenopus class II molecules have been developed. Mouse monoclonal antibodies were prepared by immunizing BALB/c mice with frog MHC antigens that had been partially purified with alloantisera, and by immunizing mouse spleen cells in vitro with activated Xenopus T lymphocytes. In addition, five mouse monoclonal antibodies specific for human class II antigens were found to cross-react with Xenopus class II antigens. A.TH mice, which do not express E class II molecules, always produce immunoprecipitating antibodies reactive with frog class II molecules after immunization with frog lymphocytes; other mouse strains rarely produce such antibodies. Two of the monoclonal antibodies raised against frog class II molecules recognize the denatured class II beta chain on Western blots, and the other three appear to recognize only the class II heterodimeric complex. The antibodies display differential reactivity with the allelic class II products of Xenopus. The monoclonal antibodies react with all adult lymphocytes in the spleen and peripheral blood, T cells and B cells having equivalent levels of class II antigens per cell. Class II molecules are "differentiation antigens" on adult thymocytes as the expression is greatest on the mature medullary population. The number of class II molecules/lymphocyte increases after culturing in medium containing fetal bovine serum. Sequential immunoprecipitation and isoelectric focusing experiments have shown that cell surface class II molecules immunoprecipitated with the monoclonal antibodies are the same as those immunoprecipitated with the cross-reactive antiserum specific for DR antigens which was previously used to identify frog class II molecules.
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Abstract
There is very little known about the long-term evolution of the MHC and MHC-like molecules. This is because both the theory (the evolutionary questions and models) and the practice (the animals systems, functional assays and reagents to identify and characterize these molecules) have been difficult to develop. There is no molecular evidence yet to decide whether vertebrate immune systems (and particularly the MHC molecules) are evolutionarily related to invertebrate allorecognition systems, and the functional evidence can be interpreted either way. Even among the vertebrates, there is great heterogeneity in the quality and quantity of the immune response. The functional evidence for T-lymphocyte function in jawless and cartilagenous fish is poor, while the bony fish seem to have many characteristics of a mammalian immune system. The organization and sequence of fish Ig genes also indicate that important events in the evolution of the immune system and the MHC occurred in the fish, but thus far there is no molecular evidence for recognizable MHC-like molecules in any fish. There is clearly an MHC in amphibians and birds with many characteristics like the MHC of mammals (a single genetic region encoding polymorphic class I and class II molecules) and evidence for polymorphic class I and class II molecules in reptiles. However, many details differ from the mammals, and it is not clear whether these reflect historical accident or selection for different lifestyles or environment. For example, the adult frog Xenopus has a vigorous immune system with many similarities to mammals, a ubiquitous class I molecule, but a much wider class II tissue distribution than human, mouse and chicken. The Xenopus tadpole has a much more restricted immune response, no cell surface class I molecules and a mammalian class II distribution. The axolotl has a very poor immune response (as though there are no helper T cells), a wide class II distribution and, for most animals, no cell surface class I molecule. It would be enlightening to understand both the mechanisms for the regulation of the MHC molecules during ontogeny and the consequences for the immune system and survival of the animals. These animals also differ markedly in the level of MHC polymorphism. Another difference from mammals is the presence of previously uncharacterized molecules. In Xenopus and reptiles, there are two populations of class I alpha chain on the surface of erythrocytes, those in association with beta 2m and those in association with a disulfide-linked homodimer.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J Kaufman
- Basel Institute for Immunology, Switzerland
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Affiliation(s)
- M F Flajnik
- Department of Microbiology and Immunology, University of Miami, FL 33101
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Holtfreter HB, Cohen N. Fixation-associated quantitative variations of DNA fluorescence observed in flow cytometric analysis of hemopoietic cells from adult diploid frogs. CYTOMETRY 1990; 11:676-85. [PMID: 1696536 DOI: 10.1002/cyto.990110604] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have examined, by flow cytometry, the apparent DNA content of frog blood cells that had been fixed with either 50% ethanol, 70% ethanol, or 66% methanol, before being stained with either mithramycin, propidium iodide, or Hoechst 33258. After 50% ethanol fixation, regardless of the dye used, the DNA content of the hemopoietic cells appeared unimodal, but after either 70% ethanol or 66% methanol fixation, it appeared bimodal. Cell sorting revealed that the lower and upper modes are represented by erythrocytes (RBCs) and leukocytes (WBCs), respectively. In amphibians, the chromatin of metabolically inactive RBCs is highly condensed relative to the chromatin of metabolically active WBCs. The bimodal distribution of DNA contents seen with 66% methanol and 70% ethanol, but not 50% ethanol, seems to reflect this disparity in the degree of chromatin condensation existing between the RBCs and WBCs. This, in turn, implies that the accessibility of fluorescent DNA dyes to the chromatin of fixed frog hemopoietic cells, especially of RBCs, can be affected by the concentration of alcohol used for their fixation.
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Affiliation(s)
- H B Holtfreter
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, New York 14642
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