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Donnarumma T, Young GR, Merkenschlager J, Eksmond U, Bongard N, Nutt SL, Boyer C, Dittmer U, Le-Trilling VTK, Trilling M, Bayer W, Kassiotis G. Opposing Development of Cytotoxic and Follicular Helper CD4 T Cells Controlled by the TCF-1-Bcl6 Nexus. Cell Rep 2017; 17:1571-1583. [PMID: 27806296 PMCID: PMC5149578 DOI: 10.1016/j.celrep.2016.10.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/31/2016] [Accepted: 10/04/2016] [Indexed: 12/18/2022] Open
Abstract
CD4+ T cells develop distinct and often contrasting helper, regulatory, or cytotoxic activities. Typically a property of CD8+ T cells, granzyme-mediated cytotoxic T cell (CTL) potential is also exerted by CD4+ T cells. However, the conditions that induce CD4+ CTLs are not entirely understood. Using single-cell transcriptional profiling, we uncover a unique signature of Granzyme B (GzmB)+ CD4+ CTLs, which distinguishes them from other CD4+ T helper (Th) cells, including Th1 cells, and strongly contrasts with the follicular helper T (Tfh) cell signature. The balance between CD4+ CTL and Tfh differentiation heavily depends on the class of infecting virus and is jointly regulated by the Tfh-related transcription factors Bcl6 and Tcf7 (encoding TCF-1) and by the expression of the inhibitory receptors PD-1 and LAG3. This unique profile of CD4+ CTLs offers targets for their study, and its antagonism by the Tfh program separates CD4+ T cells with either helper or killer functions.
Adenoviruses prime CD4 T cells with CTL potential, but retroviruses do not CD4 CTLs are transcriptionally distinguishable from other Th cells The CD4 CTL program is the direct opposite of the Tfh program CD4 CTLs are restrained by the TCF-1-Bcl6 nexus and by PD-1 and LAG3
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Research Support, Non-U.S. Gov't |
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Ottina E, Levy P, Eksmond U, Merkenschlager J, Young GR, Roels J, Stoye JP, Tüting T, Calado DP, Kassiotis G. Restoration of Endogenous Retrovirus Infectivity Impacts Mouse Cancer Models. Cancer Immunol Res 2018; 6:1292-1300. [PMID: 30143537 PMCID: PMC6485373 DOI: 10.1158/2326-6066.cir-18-0038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 06/19/2018] [Accepted: 08/21/2018] [Indexed: 12/31/2022]
Abstract
Mouse models have been instrumental in establishing fundamental principles of cancer initiation and progression and continue to be invaluable in the discovery and further development of cancer therapies. Nevertheless, important aspects of human disease are imperfectly approximated in mouse models, notably the involvement of endogenous retroviruses (ERVs). Replication-defective ERVs, present in both humans and mice, may affect tumor development and antitumor immunity through mechanisms not involving infection. Here, we revealed an adverse effect of murine ERVs with restored infectivity on the behavior of mouse cancer models. In contrast to human cancer, where infectious ERVs have never been detected, we found that ERV infectivity was frequently restored in transplantable, as well as genetic, mouse cancer models. Such replication-competent, ERV-derived retroviruses were responsible for unusually high expression of retroviral nucleic acids and proteins in mouse cancers. Infectious ERV-derived retroviruses produced by mouse cancer cells could directly infect tumor-infiltrating host immune cells and fundamentally modified the host's immune defenses to cancer, as well as the outcome of immunotherapy. Therefore, infectious retroviruses, variably arising in mouse cancer models, but not in human cancer, have the potential to confound many immunologic studies and should be considered as a variable, if not altogether avoided. Cancer Immunol Res; 6(11); 1292-300. ©2018 AACR.
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MESH Headings
- Animals
- Cell Line, Tumor
- Endogenous Retroviruses/pathogenicity
- Female
- Leukemia Virus, Murine/genetics
- Leukemia Virus, Murine/pathogenicity
- Lymphocytes, Tumor-Infiltrating/pathology
- Male
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Transgenic
- Neoplasms, Experimental/immunology
- Neoplasms, Experimental/pathology
- Neoplasms, Experimental/virology
- Positive Regulatory Domain I-Binding Factor 1/genetics
- Proto-Oncogene Proteins B-raf/genetics
- Retroviridae Infections/virology
- Viral Tropism/physiology
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Wang Z, Merkenschlager J, Chen ST, Oliveira TY, Ramos V, Gordon KM, Yao KH, Jankovic M, Nussenzweig M, Escolano A. Isolation of single HIV-1 Envelope specific B cells and antibody cloning from immunized rhesus macaques. J Immunol Methods 2020; 478:112734. [PMID: 31866284 PMCID: PMC6961706 DOI: 10.1016/j.jim.2019.112734] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 01/16/2023]
Abstract
Antibody cloning from single B cells is an essential tool for characterizing humoral immune responses and obtaining valuable therapeutic and analytical reagents. Antibody cloning from individuals with high serologic titers to HIV-1, Influenza, Malaria and ZIKV has led to new insights that inform vaccine design efforts. In contrast to humans and mice, less is known about antibody cloning from single B cells in macaques. Here, we describe a protocol to identify and purify single antigen-specific macaque B cells, and subsequently clone and produce macaque monoclonal antibodies. The sorting strategy requires the use of a combination of fluorochrome labeled antigens and omission of anti-IgG antibodies that can interfere with antigen binding and vice versa. Optimized methods for macaque antibody gene amplification, DNA preparation for antibody production and antibody screening by ELISA are also presented.
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Research Support, N.I.H., Extramural |
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Merkenschlager J, Kassiotis G. Narrowing the Gap: Preserving Repertoire Diversity Despite Clonal Selection during the CD4 T Cell Response. Front Immunol 2015; 6:413. [PMID: 26322045 PMCID: PMC4531291 DOI: 10.3389/fimmu.2015.00413] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 07/28/2015] [Indexed: 01/14/2023] Open
Abstract
T cell immunity relies on the generation and maintenance of a diverse repertoire of T cell antigen receptors (TCRs). The strength of signaling emanating from the TCR dictates the fate of T cells during development, as well as during the immune response. Whereas development of new T cells in the thymus increases the available TCR repertoire, clonal selection during the immune response narrows TCR diversity through the outgrowth of clonotypes with the fittest TCR. To ensure maintenance of TCR diversity in the antigen-selected repertoire, specific mechanisms can be envisaged that facilitate the participation of T cell clonotypes with less than best fit TCRs. Here, we summarize the evidence for the existence of such mechanisms that can prevent the loss of diversity. A number of T cell-autonomous or extrinsic factors can reverse clonotypic hierarchies set by TCR affinity for given antigen. Although not yet complete, understanding of these factors and their mechanism of action will be critical in interventional attempts to mold the antigen-selected TCR repertoire.
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Review |
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Danelli L, Cornish G, Merkenschlager J, Kassiotis G. Default polyfunctional T helper 1 response to ample signal 1 alone. Cell Mol Immunol 2021; 18:1809-1822. [PMID: 32313208 PMCID: PMC8245500 DOI: 10.1038/s41423-020-0415-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 03/14/2020] [Indexed: 12/27/2022] Open
Abstract
CD4+ T cells integrate well-defined signals from the T-cell receptor (TCR) (signal 1) and a host of costimulatory molecules (signal 2) to initiate clonal expansion and differentiation into diverse functional T helper (Th) subsets. However, our ability to guide the expansion of context-appropriate Th subsets by deploying these signals in vaccination remains limited. Using cell-based vaccines, we selectively amplified signal 1 by exclusive presentation of an optimized peptide:MHC II (pMHC II) complex in the absence of classic costimulation. Contrary to expectations, amplified signal 1 alone was strongly immunogenic and selectively expanded high-affinity TCR clonotypes, despite delivering intense TCR signals. In contrast to natural infection or standard vaccines, amplified signal 1, presented by a variety of professional and nonprofessional antigen-presenting cells (APCs), induced exclusively polyfunctional Th1 effector and memory cells, which protected against retroviral infection and tumor challenge, and expanded tumor-reactive CD4+ T cells otherwise rendered unresponsive in tumor-bearing hosts. Together, our findings uncover a default Th1 response to ample signal 1 and offer a means to selectively prime such protective responses by vaccination.
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Eksmond U, Jenkins B, Merkenschlager J, Mothes W, Stoye JP, Kassiotis G. Mutation of the Putative Immunosuppressive Domain of the Retroviral Envelope Glycoprotein Compromises Infectivity. J Virol 2017; 91:e01152-17. [PMID: 28814524 PMCID: PMC5640850 DOI: 10.1128/jvi.01152-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/13/2017] [Indexed: 01/30/2023] Open
Abstract
The envelope glycoprotein of diverse endogenous and exogenous retroviruses is considered inherently immunosuppressive. Extensive work mapped the immunosuppressive activity to a highly conserved domain, termed the immunosuppressive domain (ISD), in the transmembrane (TM) subunit of the envelope glycoprotein and identified two naturally polymorphic key residues that afford immunosuppressive activity to distinct envelope glycoproteins. Concurrent mutation of these two key residues (E14R and A20F) in the envelope glycoprotein of the Friend murine leukemia virus (F-MLV) ISD has been reported to abolish its immunosuppressive activity, without affecting its fusogenicity, and to weaken the ability of the virus to replicate specifically in immunocompetent hosts. Here, we show that mutation of these key residues did, in fact, result in a substantial loss of F-MLV infectivity, independently of host immunity, challenging whether associations exist between the two. Notably, a loss of infectivity incurred by the F-MLV mutant with the E14R and A20F double ISD mutation was conditional on expression of the ecotropic envelope receptor murine cationic amino acid transporter-1 (mCAT1) in the virus-producing cell. Indeed, the F-MLV mutant retained infectivity when it was produced by human cells, which naturally lack mCAT1 expression, but not by murine cells. Furthermore, mCAT1 overexpression in human cells impaired the infectivity of both the F-MLV double mutant and the wild-type F-MLV strain, suggesting a finely tuned relationship between the levels of mCAT1 in the producer cell and the infectivity of the virions produced. An adverse effect on this relationship, rather than disruption of the putative ISD, is therefore more likely to explain the loss of F-MLV infectivity incurred by mutations in key ISD residues E14 and A20.IMPORTANCE Retroviruses can interact with their hosts in ways that, although not entirely understood, can greatly influence their pathogenic potential. One such example is a putative immunosuppressive activity, which has been mapped to a conserved domain of the retroviral envelope glycoprotein of several exogenous as well as endogenous retroviruses. In this study, mutations naturally found in some envelope glycoproteins lacking immunosuppressive activity were shown to affect retrovirus infectivity only if the host cell that produced the retrovirus also expressed the cellular entry receptor. These findings shed light on a novel role for this conserved domain in providing the necessary stability to the envelope glycoprotein in order to withstand the interaction with the cellular receptor during virus formation. This function of the domain is critical for further elucidation of the mechanism of immunosuppression mediated by the retroviral envelope glycoprotein.
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MacLean AJ, Deimel LP, Zhou P, ElTanbouly MA, Merkenschlager J, Ramos V, Santos GS, Hagglof T, Mayer CT, Hernandez B, Gazumyan A, Nussenzweig MC. Affinity maturation of antibody responses is mediated by differential plasma cell proliferation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.11.26.625430. [PMID: 39651284 PMCID: PMC11623657 DOI: 10.1101/2024.11.26.625430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2024]
Abstract
Increased antibody affinity over time after vaccination, known as affinity maturation, is a prototypical feature of immune responses. Recent studies have shown that a diverse collection of B cells, producing antibodies with a wide spectrum of different affinities, are selected into the plasma cell (PC) pathway. How affinity-permissive selection enables PC affinity maturation remains unknown. Here we report that PC precursors (prePC) expressing high affinity antibodies receive higher levels of T follicular helper (Tfh)-derived help and divide at higher rates than their lower affinity counterparts once they leave the GC. Thus, differential cell division by selected prePCs accounts for how diverse precursors develop into a PC compartment that mediates serological affinity maturation.
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Preprint |
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Merkenschlager J, Pyo AGT, Silva Santos GS, Schaefer-Babajew D, Cipolla M, Hartweger H, Gitlin AD, Wingreen NS, Nussenzweig MC. Regulated somatic hypermutation enhances antibody affinity maturation. Nature 2025; 641:495-502. [PMID: 40108475 DOI: 10.1038/s41586-025-08728-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 01/31/2025] [Indexed: 03/22/2025]
Abstract
Germinal centres are specialized microenvironments where B cells undergo affinity maturation. B cells expressing antibodies whose affinity is improved by somatic hypermutation are selected for expansion by limiting numbers of T follicular helper cells. Cell division is accompanied by mutation of the immunoglobulin genes, at what is believed to be a fixed rate of around 1 × 10-3 per base pair per cell division1. As mutagenesis is random, the probability of acquiring deleterious mutations outweighs the probability of acquiring affinity-enhancing mutations. This effect might be heightened, and even become counterproductive, in B cells that express high-affinity antibodies and undergo the greatest number of cell divisions2. Here we experimentally examine a theoretical model that explains how affinity maturation could be optimized by varying the rate of somatic hypermutation such that cells that express higher-affinity antibodies divide more but mutate less per division. Data obtained from mice immunized with SARS-CoV-2 vaccines or a model antigen align with the theoretical model and show that cells producing high-affinity antibodies shorten the G0/G1 phases of the cell cycle and reduce their mutation rates. We propose that these mechanisms safeguard high-affinity B cell lineages and enhance the outcomes of antibody affinity maturation.
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Oliveira TY, Merkenschlager J, Eisenreich T, Bortolatto J, Yao KH, Gatti DM, Churchill GA, Nussenzweig MC, Breton G. Quantitative trait loci mapping provides insights into the genetic regulation of dendritic cell numbers in mouse tissues. Cell Rep 2024; 43:114296. [PMID: 38823019 PMCID: PMC11726347 DOI: 10.1016/j.celrep.2024.114296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/02/2024] [Accepted: 05/14/2024] [Indexed: 06/03/2024] Open
Abstract
To explore the influence of genetics on homeostatic regulation of dendritic cell (DC) numbers, we present a screen of DCs and their progenitors in lymphoid and non-lymphoid tissues in Collaborative Cross (CC) and Diversity Outbred (DO) mice. We report 30 and 71 loci with logarithm of the odds (LOD) scores >8.18 and ranging from 6.67 to 8.19, respectively. The analysis reveals the highly polygenic and pleiotropic architecture of this complex trait, including many of the previously identified genetic regulators of DC development and maturation. Two SNPs in genes potentially underlying variation in DC homeostasis, a splice variant in Gramd4 (rs235532740) and a missense variant in Orai3 (rs216659754), are confirmed by gene editing using CRISPR-Cas9. Gramd4 is a central regulator of DC homeostasis that impacts the entire DC lineage, and Orai3 regulates cDC2 numbers in tissues. Overall, the data reveal a large number of candidate genes regulating DC homeostasis in vivo.
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Research Support, N.I.H., Extramural |
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MacLean AJ, Deimel LP, Zhou P, ElTanbouly MA, Merkenschlager J, Ramos V, Santos GS, Hägglöf T, Mayer CT, Hernandez B, Gazumyan A, Nussenzweig MC. Affinity maturation of antibody responses is mediated by differential plasma cell proliferation. Science 2025; 387:413-420. [PMID: 39700316 PMCID: PMC11938350 DOI: 10.1126/science.adr6896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Revised: 10/08/2024] [Accepted: 11/28/2024] [Indexed: 12/21/2024]
Abstract
Increased antibody affinity over time after vaccination, known as affinity maturation, is a prototypical feature of immune responses. Recent studies have shown that a diverse collection of B cells, producing antibodies with a wide spectrum of different affinities, is selected into the plasma cell (PC) pathway. How affinity-permissive selection enables PC affinity maturation remains unknown. We found that PC precursors (prePCs) expressing high-affinity antibodies received higher levels of T follicular helper cell (TFH cell)-derived help and divided at higher rates compared with their lower-affinity counterparts once they left the germinal center. Our findings indicate that differential cell division by selected prePCs accounts for how diverse precursors develop into a PC compartment that mediates serological affinity maturation.
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Merkenschlager J, Berz RM, Ramos V, Uhlig M, MacLean AJ, Nowosad CR, Oliveira TY, Nussenzweig MC. Continually recruited naïve T cells contribute to the follicular helper and regulatory T cell pools in germinal centers. Nat Commun 2023; 14:6944. [PMID: 37907454 PMCID: PMC10618265 DOI: 10.1038/s41467-023-41880-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/20/2023] [Indexed: 11/02/2023] Open
Abstract
Follicular helper T cells (TFH) mediate B cell selection and clonal expansion in germinal centers (GCs), and follicular regulatory T cells (TFR) prevent the emergence of self-reactive B cells and help to extinguish the reaction. Here we show that GC reactions continually recruit T cells from both the naïve conventional and naive thymic regulatory T cell (Treg) repertoires. In the early GC, newly recruited T cells develop into TFH, whereas cells entering during the contraction phase develop into TFR cells that contribute to GC dissolution. The TFR fate decision is associated with decreased antigen availability and is modulated by slow antigen delivery or mRNA vaccination. Thus, invasion of ongoing GCs by newly developing TFH and TFR helps remodel the GC based on antigen availability.
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Mavrommatis B, Baudino L, Levy P, Merkenschlager J, Eksmond U, Donnarumma T, Young G, Stoye J, Kassiotis G. Dichotomy between T Cell and B Cell Tolerance to Neonatal Retroviral Infection Permits T Cell Therapy. THE JOURNAL OF IMMUNOLOGY 2016; 197:3628-3638. [PMID: 27647833 PMCID: PMC5073355 DOI: 10.4049/jimmunol.1600734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/05/2016] [Indexed: 11/23/2022]
Abstract
Elucidation of the immune requirements for control or elimination of retroviral infection remains an important aim. We studied the induction of adaptive immunity to neonatal infection with a murine retrovirus, under conditions leading to immunological tolerance. We found that the absence of either maternal or offspring adaptive immunity permitted efficient vertical transmission of the retrovirus. Maternal immunodeficiency allowed the retrovirus to induce central Th cell tolerance in the infected offspring. In turn, this compromised the offspring’s ability to mount a protective Th cell–dependent B cell response. However, in contrast to T cells, offspring B cells were not centrally tolerized and retained their ability to respond to the infection when provided with T cell help. Thus, escape of retrovirus-specific B cells from deletional tolerance offers the opportunity to induce protective retroviral immunity by restoration of retrovirus-specific T cell help, suggesting similar T cell immunotherapies for persistent viral infections.
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Research Support, Non-U.S. Gov't |
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