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De Boer RJ, Kesmir C, Perelson AS, Borghans JAM. Is the exquisite specificity of lymphocytes generated by thymic selection or due to evolution? Front Immunol 2024; 15:1266349. [PMID: 38605941 PMCID: PMC11008227 DOI: 10.3389/fimmu.2024.1266349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 03/11/2024] [Indexed: 04/13/2024] Open
Abstract
We have previously argued that the antigen receptors of T and B lymphocytes evolved to be sufficiently specific to avoid massive deletion of clonotypes by negative selection. Their optimal 'specificity' level, i.e., probability of binding any particular epitope, was shown to be inversely related to the number of self-antigens that the cells have to be tolerant to. Experiments have demonstrated that T lymphocytes also become more specific during negative selection in the thymus, because cells expressing the most crossreactive receptors have the highest likelihood of binding a self-antigen, and hence to be tolerized (i.e., deleted, anergized, or diverted into a regulatory T cell phenotype). Thus, there are two -not mutually exclusive- explanations for the exquisite specificity of T cells, one involving evolution and the other thymic selection. To better understand the impact of both, we extend a previously developed mathematical model by allowing for T cells with very different binding probabilities in the pre-selection repertoire. We confirm that negative selection tends to tolerize the most crossreactive clonotypes. As a result, the average level of specificity in the functional post-selection repertoire depends on the number of self-antigens, even if there is no evolutionary optimization of binding probabilities. However, the evolutionary optimal range of binding probabilities in the pre-selection repertoire also depends on the number of self-antigens. Species with more self antigens need more specific pre-selection repertoires to avoid excessive loss of T cells during thymic selection, and hence mount protective immune responses. We conclude that both evolution and negative selection are responsible for the high level of specificity of lymphocytes.
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Affiliation(s)
- Rob J. De Boer
- Theoretical Biology and Bioinformatics, Utrecht University, Utrecht, Netherlands
| | - Can Kesmir
- Theoretical Biology and Bioinformatics, Utrecht University, Utrecht, Netherlands
| | - Alan S. Perelson
- Department of Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - José A. M. Borghans
- Center for Translational Immunology, University Medical Center Utrecht, Utrecht, Netherlands
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2
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Giorgetti OB, O'Meara CP, Schorpp M, Boehm T. Origin and evolutionary malleability of T cell receptor α diversity. Nature 2023:10.1038/s41586-023-06218-x. [PMID: 37344590 PMCID: PMC10322711 DOI: 10.1038/s41586-023-06218-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 05/12/2023] [Indexed: 06/23/2023]
Abstract
Lymphocytes of vertebrate adaptive immune systems acquired the capability to assemble, from split genes in the germline, billions of functional antigen receptors1-3. These receptors show specificity; unlike the broadly tuned receptors of the innate system, antibodies (Ig) expressed by B cells, for instance, can accurately distinguish between the two enantiomers of organic acids4, whereas T cell receptors (TCRs) reliably recognize single amino acid replacements in their peptide antigens5. In developing lymphocytes, antigen receptor genes are assembled from a comparatively small set of germline-encoded genetic elements in a process referred to as V(D)J recombination6,7. Potential self-reactivity of some antigen receptors arising from the quasi-random somatic diversification is suppressed by several robust control mechanisms8-12. For decades, scientists have puzzled over the evolutionary origin of somatically diversifying antigen receptors13-16. It has remained unclear how, at the inception of this mechanism, immunologically beneficial expanded receptor diversity was traded against the emerging risk of destructive self-recognition. Here we explore the hypothesis that in early vertebrates, sequence microhomologies marking the ends of recombining elements became the crucial targets of selection determining the outcome of non-homologous end joining-based repair of DNA double-strand breaks generated during RAG-mediated recombination. We find that, across the main clades of jawed vertebrates, TCRα repertoire diversity is best explained by species-specific extents of such sequence microhomologies. Thus, selection of germline sequence composition of rearranging elements emerges as a major factor determining the degree of diversity of somatically generated antigen receptors.
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Affiliation(s)
- Orlando B Giorgetti
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
| | - Connor P O'Meara
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Michael Schorpp
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Thomas Boehm
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany.
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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3
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Paiola M, Dimitrakopoulou D, Pavelka MS, Robert J. Amphibians as a model to study the role of immune cell heterogeneity in host and mycobacterial interactions. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 139:104594. [PMID: 36403788 DOI: 10.1016/j.dci.2022.104594] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 06/16/2023]
Abstract
Mycobacterial infections represent major concerns for aquatic and terrestrial vertebrates including humans. Although our current knowledge is mostly restricted to Mycobacterium tuberculosis and mammalian host interactions, increasing evidence suggests common features in endo- and ectothermic animals infected with non-tuberculous mycobacteria (NTMs) like those described for M. tuberculosis. Importantly, most of the pathogenic and non-pathogenic NTMs detected in amphibians from wild, farmed, and research facilities represent, in addition to the potential economic loss, a rising concern for human health. Upon mycobacterial infection in mammals, the protective immune responses involving the innate and adaptive immune systems are highly complex and therefore not fully understood. This complexity results from the versatility and resilience of mycobacteria to hostile conditions as well as from the immune cell heterogeneity arising from the distinct developmental origins according with the concept of layered immunity. Similar to the differing responses of neonates versus adults during tuberculosis development, the pathogenesis and inflammatory responses are stage-specific in Xenopus laevis during infection by the NTM M. marinum. That is, both in human fetal and neonatal development and in tadpole development, responses are characterized by hypo-responsiveness and a lower capacity to contain mycobacterial infections. Similar to a mammalian fetus and neonates, T cells and myeloid cells in Xenopus tadpoles and axolotls are different from the adult immune cells. Fetal and amphibian larval T cells, which are characterized by a lower T cell receptor (TCR) repertoire diversity, are biased toward regulatory function, and they have distinct progenitor origins from those of the adult immune cells. Some early developing T cells and likely macrophage subpopulations are conserved in adult anurans and mammals, and therefore, they likely play an important role in the host-pathogen interactions from early stages of development to adulthood. Thus, we propose the use of developing amphibians, which have the advantage of being free-living early in their development, as an alternative and complementary model to study the role of immune cell heterogeneity in host-mycobacteria interactions.
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Affiliation(s)
- Matthieu Paiola
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Dionysia Dimitrakopoulou
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Martin S Pavelka
- 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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4
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Human thymoma-associated mutation of the GTF2I transcription factor impairs thymic epithelial progenitor differentiation in mice. Commun Biol 2022; 5:1037. [PMID: 36175547 PMCID: PMC9522929 DOI: 10.1038/s42003-022-04002-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/14/2022] [Indexed: 12/04/2022] Open
Abstract
Few human tumours present with a recurrent pathognomonic mutation in a transcription factor. Thymomas are an exception, with the majority of some subtypes exhibiting a distinct somatically acquired missense mutation in the general transcription factor GTF2I. Co-dominant expression of wild-type and mutated forms of Gtf2i in the mouse thymic epithelium is associated with aberrant thymic architecture and reduced thymopoietic activity. Phenotypic and molecular characterization of the mutant epithelium indicates that medullary differentiation is particularly affected as a result of impaired differentiation of bi-potent epithelial progenitors. The resulting gene expression signature is dominated by that of immature cortex-like thymic epithelial cells. TCR repertoire analysis of the cytopenic T cell compartment indicates efficient intrathymic selection; hence, despite marked homeostatic proliferation of T cell clones, autoimmunity is not observed. Thus, our transgenic mouse model recapitulates some aspects of the pathophysiology of a genetically defined type of human thymoma. Thymic architecture and T cell repertoire analysis of a mouse model for thymoma and the role of the transcription factor GTF2I shows suitability of this model to recapitulate human thymomas and a severe effect of Gtf2i mutations on the medullary compartment.
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5
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Crider J, Quiniou SMA, Felch KL, Showmaker K, Bengtén E, Wilson M. A Comprehensive Annotation of the Channel Catfish ( Ictalurus punctatus) T Cell Receptor Alpha/Delta, Beta, and Gamma Loci. Front Immunol 2021; 12:786402. [PMID: 34899754 PMCID: PMC8656973 DOI: 10.3389/fimmu.2021.786402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/05/2021] [Indexed: 12/28/2022] Open
Abstract
The complete germline repertoires of the channel catfish, Ictalurus punctatus, T cell receptor (TR) loci, TRAD, TRB, and TRG were obtained by analyzing genomic data from PacBio sequencing. The catfish TRB locus spans 214 kb, and contains 112 TRBV genes, a single TRBD gene, 31 TRBJ genes and two TRBC genes. In contrast, the TRAD locus is very large, at 1,285 kb. It consists of four TRDD genes, one TRDJ gene followed by the exons for TRDC, 125 TRAJ genes and the exons encoding the TRAC. Downstream of the TRAC, are 140 TRADV genes, and all of them are in the opposite transcriptional orientation. The catfish TRGC locus spans 151 kb and consists of four diverse V-J-C cassettes. Altogether, this locus contains 15 TRGV genes and 10 TRGJ genes. To place our data into context, we also analyzed the zebrafish TR germline gene repertoires. Overall, our findings demonstrated that catfish possesses a more restricted repertoire compared to the zebrafish. For example, the 140 TRADV genes in catfish form eight subgroups based on members sharing 75% nucleotide identity. However, the 149 TRAD genes in zebrafish form 53 subgroups. This difference in subgroup numbers between catfish and zebrafish is best explained by expansions of catfish TRADV subgroups, which likely occurred through multiple, relatively recent gene duplications. Similarly, 112 catfish TRBV genes form 30 subgroups, while the 51 zebrafish TRBV genes are placed into 36 subgroups. Notably, several catfish and zebrafish TRB subgroups share ancestor nodes. In addition, the complete catfish TR gene annotation was used to compile a TR gene segment database, which was applied in clonotype analysis of an available gynogenetic channel catfish transcriptome. Combined, the TR annotation and clonotype analysis suggested that the expressed TRA, TRB, and TRD repertoires were generated by different mechanisms. The diversity of the TRB repertoire depends on the number of TRBV subgroups and TRBJ genes, while TRA diversity relies on the many different TRAJ genes, which appear to be only minimally trimmed. In contrast, TRD diversity relies on nucleotide additions and the utilization of up to four TRDD segments.
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Affiliation(s)
- Jonathan Crider
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Sylvie M A Quiniou
- Warmwater Aquaculture Research Unit, United States Department of Agriculture - Agricultural Research Service (USDA-ARS), Stoneville, MS, United States
| | - Kristianna L Felch
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Kurt Showmaker
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States.,Department of Data Science, John D. Bower School of Population Health, University of Mississippi Medical Center, Jackson, MS, United States
| | - Eva Bengtén
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
| | - Melanie Wilson
- Department of Microbiology and Immunology, University of Mississippi Medical Center, Jackson, MS, United States
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6
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O'Meara CP, Guerri L, Lawir DF, Mateos F, Iconomou M, Iwanami N, Soza-Ried C, Sikora K, Siamishi I, Giorgetti O, Peter S, Schorpp M, Boehm T. Genetic landscape of T cells identifies synthetic lethality for T-ALL. Commun Biol 2021; 4:1201. [PMID: 34671088 PMCID: PMC8528931 DOI: 10.1038/s42003-021-02694-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 09/17/2021] [Indexed: 11/09/2022] Open
Abstract
To capture the global gene network regulating the differentiation of immature T cells in an unbiased manner, large-scale forward genetic screens in zebrafish were conducted and combined with genetic interaction analysis. After ENU mutagenesis, genetic lesions associated with failure of T cell development were identified by meiotic recombination mapping, positional cloning, and whole genome sequencing. Recessive genetic variants in 33 genes were identified and confirmed as causative by additional experiments. The mutations affected T cell development but did not perturb the development of an unrelated cell type, growth hormone-expressing somatotrophs, providing an important measure of cell-type specificity of the genetic variants. The structure of the genetic network encompassing the identified components was established by a subsequent genetic interaction analysis, which identified many instances of positive (alleviating) and negative (synthetic) genetic interactions. Several examples of synthetic lethality were subsequently phenocopied using combinations of small molecule inhibitors. These drugs not only interfered with normal T cell development, but also elicited remission in a model of T cell acute lymphoblastic leukaemia. Our findings illustrate how genetic interaction data obtained in the context of entire organisms can be exploited for targeted interference with specific cell types and their malignant derivatives.
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Affiliation(s)
- Connor P O'Meara
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Lucia Guerri
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
- Laboratory of Neurogenetics, National Institute of Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Divine-Fondzenyuy Lawir
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
- Institute of Zoology, Developmental Biology Unit, University of Cologne, Cologne, Germany
| | - Fernando Mateos
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Mary Iconomou
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Norimasa Iwanami
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
- Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Japan
| | - Cristian Soza-Ried
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
- Fundacion Oncoloop & Center for Nuclear Medicine, Santiago, Chile
| | - Katarzyna Sikora
- Bioinformatics Unit, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Iliana Siamishi
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Orlando Giorgetti
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Sarah Peter
- Bioinformatics Unit, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Michael Schorpp
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany
| | - Thomas Boehm
- Department of Developmental Immunology, Max Planck Institute of Immunobiology and Epigenetics, 79108, Freiburg, Germany.
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.
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7
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Castro R, Navelsaker S, Collet B, Jouneau L, Bochet P, Quillet E, Evensen Ø, Sunyer JO, Fillatreau S, Bruhns P, Rose T, Huetz F, Boudinot P. Cutting Edge: Neutralizing Public Antibody Responses Are an Ancient Form of Defense Conserved in Fish and Mammals. THE JOURNAL OF IMMUNOLOGY 2021; 207:371-375. [PMID: 34233911 DOI: 10.4049/jimmunol.2100149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/16/2021] [Indexed: 11/19/2022]
Abstract
The repertoire of Abs is generated by genomic rearrangements during B cell differentiation. Although V(D)J rearrangements lead to repertoires mostly different between individuals, recent studies have shown that they contain a substantial fraction of overrepresented and shared "public" clones. We previously reported a strong public IgHμ clonotypic response against the rhabdovirus viral hemorrhagic septicemia virus in a teleost fish. In this study, we identified an IgL chain associated with this public response that allowed us to characterize its functionality. We show that this public Ab response has a potent neutralizing capacity that is typically associated with host protection during rhabdovirus infections. We also demonstrate that the public response is not restricted to a particular trout isogenic line but expressed in multiple genetic backgrounds and may be used as a marker of successful vaccination. Our work reveals that public B cell responses producing generic Abs constitute a mechanism of protection against infection conserved across vertebrates.
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Affiliation(s)
- Rosario Castro
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Sofie Navelsaker
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Oslo, Norway
| | - Bertrand Collet
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Luc Jouneau
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Pascal Bochet
- Bioimage Analysis Unit, Department of Cell Biology and Infection, Institut Pasteur, CNRS-UMR3691, Paris, France
| | - Edwige Quillet
- Université Paris-Saclay, INRAE, GABI, Jouy-en-Josas, France
| | - Øystein Evensen
- Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine, Oslo, Norway
| | - J Oriol Sunyer
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
| | - Simon Fillatreau
- Department of Immunology, Infectiology and Haematology (I2H), Institut Necker-Enfants Malades, INSERM U1151-CNRS UMR 8253, Paris, France.,Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris, France.,AP-HP, Hôpital Necker-Enfants Malades, Paris, France
| | - Pierre Bruhns
- Unit of Antibodies in Therapy and Pathology, Institut Pasteur, UMR 1222 INSERM, Paris, France; and
| | - Thierry Rose
- Lymphocyte Cell Biology Unit, INSERM 1221, Institut Pasteur, Paris, France
| | - François Huetz
- Unit of Antibodies in Therapy and Pathology, Institut Pasteur, UMR 1222 INSERM, Paris, France; and
| | - Pierre Boudinot
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France;
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