1
|
Abstract
Simple Summary Cancer genomes can undergo major restructurings involving many chromosomal locations at key stages in tumor development. This restructuring process has been designated “genome chaos” by some authors. In order to examine how chaotic cancer genome restructuring may be, the cell and molecular processes for DNA restructuring are reviewed. Examination of the action of these processes in various cancers reveals a degree of specificity that indicates genome restructuring may be sufficiently reproducible to enable possible therapies that interrupt tumor progression to more lethal forms. Abstract Cancer genomes evolve in a punctuated manner during tumor evolution. Abrupt genome restructuring at key steps in this evolution has been called “genome chaos.” To answer whether widespread genome change is truly chaotic, this review (i) summarizes the limited number of cell and molecular systems that execute genome restructuring, (ii) describes the characteristic signatures of DNA changes that result from activity of those systems, and (iii) examines two cases where genome restructuring is determined to a significant degree by cell type or viral infection. The conclusion is that many restructured cancer genomes display sufficiently unchaotic signatures to identify the cellular systems responsible for major oncogenic transitions, thereby identifying possible targets for therapies to inhibit tumor progression to greater aggressiveness.
Collapse
|
2
|
Abstract
B cells constitute a main branch adaptive immune system. They mediate host defence through the production of high-affinity antibodies against an enormous diversity of foreign antigens. Remarkably, B cells undergo multiple types of somatic DNA mutation to achieve this effector function, including class switch recombination (CSR) and somatic hypermutation (SHM). These processes occur in response to antigen recognition and inflammatory signals, and require strict biological control at multiple levels. Transcription within the locus that encodes antibodies plays direct roles in CSR. Additional non-coding RNAs (ncRNAs), including both microRNAs (miRNAs) and long ncRNAs (lncRNAs), also play pivotal roles in B cell activation and terminal effector function through post-transcriptional gene regulation and chromatin remodelling, respectively.
Collapse
Affiliation(s)
- Eric J Wigton
- Department of Microbiology & Immunology, Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA, USA
| | - K Mark Ansel
- Department of Microbiology & Immunology, Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA, USA
| |
Collapse
|
3
|
Moeini Shad T, Yousefi B, Amirifar P, Delavari S, Rae W, Kokhaei P, Abolhassani H, Aghamohammadi A, Yazdani R. Variable Abnormalities in T and B Cell Subsets in Ataxia Telangiectasia. J Clin Immunol 2020; 41:76-88. [PMID: 33052516 DOI: 10.1007/s10875-020-00881-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/29/2020] [Indexed: 01/03/2023]
Abstract
BACKGROUND Ataxia-telangiectasia (AT) is a rare genetic condition, caused by biallelic deleterious variants in the ATM gene, and has variable immunological abnormalities. This study aimed to examine immunologic parameters reflecting cell development, activation, proliferation, and class switch recombination (CSR) and determine their relationship to the clinical phenotype in AT patients. METHODS In this study, 40 patients with a confirmed diagnosis of AT from the Iranian immunodeficiency registry center and 28 age-sex matched healthy controls were enrolled. We compared peripheral B and T cell subsets and T cell proliferation response to CD3/CD28 stimulation in AT patients with and without CSR defects using flow cytometry. RESULTS A significant decrease in naïve, transitional, switched memory, and IgM only memory B cells, along with a sharp increase in the marginal zone-like and CD21low B cells was observed in the patients. We also found CD4+ and CD8+ naïve, central memory, and terminally differentiated effector memory CD4+ (TEMRA) T cells were decreased. CD4+ and CD8+ effector memory, CD8+ TEMRA, and CD4+ regulatory T cells were significantly elevated in our patients. CD4+ T cell proliferation was markedly impaired compared to the healthy controls. Moreover, immunological investigations of 15 AT patients with CSR defect revealed a significant reduction in the marginal zone, switched memory, and more intense defects in IgM only memory B cells, CD4+ naïve and central memory T cells. CONCLUSION The present study revealed that patients with AT have a broad spectrum of cellular and humoral deficiencies. Therefore, a detailed evaluation of T and B cell subsets increases understanding of the disease in patients and the risk of infection.
Collapse
Affiliation(s)
- Tannaz Moeini Shad
- Department of Immunology, Semnan University of Medical Sciences, Semnan, Iran.,Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahman Yousefi
- Department of Immunology, Semnan University of Medical Sciences, Semnan, Iran
| | - Parisa Amirifar
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Samaneh Delavari
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - William Rae
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, Cambridge, UK.,Department of Medicine, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
| | - Parviz Kokhaei
- Cancer Research Center, Semnan University of Medical Sciences, Semnan, Iran.,Department of Oncology-Pathology, BioClinicum, Karolinska University Hospital Solna and Karolinska Institutet, Stockholm, Sweden
| | - Hassan Abolhassani
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Primary Immunodeficiencies, Iran University of Medical Sciences, Tehran, Iran.,Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institute at Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Asghar Aghamohammadi
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Reza Yazdani
- Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
| |
Collapse
|
4
|
Jaiswal A, Singh AK, Tamrakar A, Kodgire P. Unfolding the Role of Splicing Factors and RNA Debranching in AID Mediated Antibody Diversification. Int Rev Immunol 2020; 40:289-306. [PMID: 32924658 DOI: 10.1080/08830185.2020.1815725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Activated B-cells diversify their antibody repertoire via somatic hypermutation (SHM) and class switch recombination (CSR). SHM is restricted to the variable region, whereas, CSR is confined to the constant region of immunoglobulin (Ig) genes. Activation-induced cytidine deaminase (AID) is a crucial player in the diversification of antibodies in the activated B-cell. AID catalyzes the deamination of cytidine (C) into uracil (U) at Ig genes. Subsequently, low fidelity repair of U:G mismatches may lead to mutations. Transcription is essential for the AID action, as it provides a transient single-strand DNA substrate. Since splicing is a co-transcriptional event, various splicing factors or regulators influence the transcription. Numerous splicing factors are known to regulate the AID targeting, function, Ig transcription, and AID splicing, which eventually influence antibody diversification processes. Splicing regulator SRSF1-3, a splicing isoform of serine arginine-rich splicing factor (SRSF1), and CTNNBL1, a spliceosome interacting factor, interact with AID and play a critical role in SHM. Likewise, a splicing regulator polypyrimidine tract binding protein-2 (PTBP2) and the debranching enzyme (DBR1) debranches primary switch transcripts which later forms G-quadruplex structures, and the S region guide RNAs direct AID to S region DNA. Moreover, AID shows several alternate splicing isoforms, like AID devoid of exon-4 (AIDΔE4) that is expressed in various pathological conditions. Interestingly, RBM5, a splicing regulator, is responsible for the skipping of AID exon 4. In this review, we discuss the role and significance of splicing factors in the AID mediated antibody diversification.
Collapse
Affiliation(s)
- Ankit Jaiswal
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, India
| | - Amit Kumar Singh
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, India
| | - Anubhav Tamrakar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, India
| | - Prashant Kodgire
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Indore, Madhya Pradesh, India
| |
Collapse
|
5
|
Stratigopoulou M, van Dam TP, Guikema JEJ. Base Excision Repair in the Immune System: Small DNA Lesions With Big Consequences. Front Immunol 2020; 11:1084. [PMID: 32547565 PMCID: PMC7272602 DOI: 10.3389/fimmu.2020.01084] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022] Open
Abstract
The integrity of the genome is under constant threat of environmental and endogenous agents that cause DNA damage. Endogenous damage is particularly pervasive, occurring at an estimated rate of 10,000–30,000 per cell/per day, and mostly involves chemical DNA base lesions caused by oxidation, depurination, alkylation, and deamination. The base excision repair (BER) pathway is primary responsible for removing and repairing these small base lesions that would otherwise lead to mutations or DNA breaks during replication. Next to preventing DNA mutations and damage, the BER pathway is also involved in mutagenic processes in B cells during immunoglobulin (Ig) class switch recombination (CSR) and somatic hypermutation (SHM), which are instigated by uracil (U) lesions derived from activation-induced cytidine deaminase (AID) activity. BER is required for the processing of AID-induced lesions into DNA double strand breaks (DSB) that are required for CSR, and is of pivotal importance for determining the mutagenic outcome of uracil lesions during SHM. Although uracils are generally efficiently repaired by error-free BER, this process is surprisingly error-prone at the Ig loci in proliferating B cells. Breakdown of this high-fidelity process outside of the Ig loci has been linked to mutations observed in B-cell tumors and DNA breaks and chromosomal translocations in activated B cells. Next to its role in preventing cancer, BER has also been implicated in immune tolerance. Several defects in BER components have been associated with autoimmune diseases, and animal models have shown that BER defects can cause autoimmunity in a B-cell intrinsic and extrinsic fashion. In this review we discuss the contribution of BER to genomic integrity in the context of immune receptor diversification, cancer and autoimmune diseases.
Collapse
Affiliation(s)
- Maria Stratigopoulou
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Tijmen P van Dam
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
6
|
Shukla V, Halabelian L, Balagere S, Samaniego-Castruita D, Feldman DE, Arrowsmith CH, Rao A, Aravind L. HMCES Functions in the Alternative End-Joining Pathway of the DNA DSB Repair during Class Switch Recombination in B Cells. Mol Cell 2019; 77:384-394.e4. [PMID: 31806351 DOI: 10.1016/j.molcel.2019.10.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/06/2019] [Accepted: 10/22/2019] [Indexed: 01/08/2023]
Abstract
HMCES (5hmC binding, embryonic stem cell-specific-protein), originally identified as a protein capable of binding 5-hydroxymethylcytosine (5hmC), an epigenetic modification generated by TET proteins, was previously reported to covalently crosslink to DNA at abasic sites via a conserved cysteine. We show here that Hmces-deficient mice display normal hematopoiesis without global alterations in 5hmC. HMCES specifically enables DNA double-strand break repair through the microhomology-mediated alternative-end-joining (Alt-EJ) pathway during class switch recombination (CSR) in B cells, and HMCES deficiency leads to a significant defect in CSR. HMCES mediates Alt-EJ through its SOS-response-associated-peptidase domain (SRAPd), a function that requires DNA binding but is independent of its autopeptidase and DNA-crosslinking activities. We show that HMCES is recruited to switch regions of the immunoglobulin locus and provide a potential structural basis for the interaction of HMCES with long DNA overhangs generated by Alt-EJ during CSR. Our studies provide further evidence for a specialized role for HMCES in DNA repair.
Collapse
Affiliation(s)
- Vipul Shukla
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - Levon Halabelian
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Sanjana Balagere
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - Daniela Samaniego-Castruita
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA
| | - Douglas E Feldman
- Department of Pathology, University of Southern California, Keck School of Medicine, Los Angeles, CA 93033, USA
| | - Cheryl H Arrowsmith
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Anjana Rao
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA; Department of Pharmacology and Moores Cancer Center, University of San Diego, California, 9500 Gilman Drive, La Jolla, CA 92093, USA; Sanford Consortium for Regenerative Medicine, 2880 Torrey Pines Scenic Drive, La Jolla, CA 92037, USA.
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
| |
Collapse
|
7
|
Zhao H, Yang J, Qian Q, Wu M, Li M, Xu W. Mesenteric CD103 +DCs Initiate Switched Coxsackievirus B3 VP1-Specific IgA Response to Intranasal Chitosan-DNA Vaccine Through Secreting BAFF/IL-6 and Promoting Th17/Tfh Differentiation. Front Immunol 2018; 9:2986. [PMID: 30619341 PMCID: PMC6305319 DOI: 10.3389/fimmu.2018.02986] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 12/04/2018] [Indexed: 01/08/2023] Open
Abstract
Intranasal chitosan-formulated DNA vaccination promotes IgA secretion in the intestine. However, the mechanism whereby chitosan-DNA skews IgA class switch recombination (CSR) of B cells in the Gut-associated lymph tissue (GALT) is not fully resolved. In this study, we investigated the effects of nasally administered chitosan-DNA (pcDNA3.1-VP1 plasmid encoding VP1 capsid protein of Coxsackievirus B3) on IgA production, DC activation and Tfh/Th17 response in the intestine. Compared to DNA immunization, intranasal chitosan-DNA vaccination induced antigen-specific IgA production in feces, a pronounced switching of antigen-specific IgA+ plasmablast B cells in the mesenteric lymph nodes (MLNs) and an enhanced expression of post-recombination Iα-CH transcripts/IgA germline transcript (αGT) as well as activation-induced cytidine deaminase (AID) in MLN B cells. MLN Tfh frequency was markedly enhanced by chitosan-DNA, and was associated with VP1-specific IgA titer. 24 h after immunization, intranasal chitosan-DNA induced a recruitment of CD103+DCs into the MLN that paralleled a selective loss of CD103+DCs in the lamina propria (LP). In vivo activated MLN-derived CD103+DCs produced high levels of IL-6 and BAFF in response to chitosan-DNA, which up-regulated transmembrane activator and CAML interactor (TACI) expression on MLN B cells. Upon co-culture with IgM+B in the presence of chitosan-DNA, MLN CD103+DCs induced IgA production in a T-dependent manner; and this IgA-promoting effect of CD103+DC was blocked by targeting TACI and, to a lower extent, by blocking IL-6. MLN CD103+DCs displayed an enhanced capacity to induce an enhanced CD4+Th17 response in vivo and in vitro, and IL-17A deficient mice had a pronounced reduction of specific intestinal IgA following immunization. Taken together, mesenteric CD103+DCs are indispensable for the adjuvant activity of chitosan in enhancing DNA vaccine-specific IgA switching in gut through activating BAFF-TACI and IL-6-IL-6R signaling, and through inducing Th17/Tfh differentiation in the MLN.
Collapse
Affiliation(s)
- Haoxin Zhao
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Jie Yang
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Qian Qian
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Manli Wu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Min Li
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Wei Xu
- Jiangsu Key Laboratory of Infection and Immunity, Institutes of Biology and Medical Sciences, Soochow University, Suzhou, China
| |
Collapse
|
8
|
Bahjat M, Guikema JEJ. The Complex Interplay between DNA Injury and Repair in Enzymatically Induced Mutagenesis and DNA Damage in B Lymphocytes. Int J Mol Sci 2017; 18:ijms18091876. [PMID: 28867784 PMCID: PMC5618525 DOI: 10.3390/ijms18091876] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/24/2017] [Accepted: 08/29/2017] [Indexed: 11/25/2022] Open
Abstract
Lymphocytes are endowed with unique and specialized enzymatic mutagenic properties that allow them to diversify their antigen receptors, which are crucial sensors for pathogens and mediators of adaptive immunity. During lymphocyte development, the antigen receptors expressed by B and T lymphocytes are assembled in an antigen-independent fashion by ordered variable gene segment recombinations (V(D)J recombination), which is a highly ordered and regulated process that requires the recombination activating gene products 1 & 2 (RAG1, RAG2). Upon activation by antigen, B lymphocytes undergo additional diversifications of their immunoglobulin B-cell receptors. Enzymatically induced somatic hypermutation (SHM) and immunoglobulin class switch recombination (CSR) improves the affinity for antigen and shape the effector function of the humoral immune response, respectively. The activation-induced cytidine deaminase (AID) enzyme is crucial for both SHM and CSR. These processes have evolved to both utilize as well as evade different DNA repair and DNA damage response pathways. The delicate balance between enzymatic mutagenesis and DNA repair is crucial for effective immune responses and the maintenance of genomic integrity. Not surprisingly, disturbances in this balance are at the basis of lymphoid malignancies by provoking the formation of oncogenic mutations and chromosomal aberrations. In this review, we discuss recent mechanistic insight into the regulation of RAG1/2 and AID expression and activity in lymphocytes and the complex interplay between these mutagenic enzymes and DNA repair and DNA damage response pathways, focusing on the base excision repair and mismatch repair pathways. We discuss how disturbances of this interplay induce genomic instability and contribute to oncogenesis.
Collapse
Affiliation(s)
- Mahnoush Bahjat
- Department of Pathology, Academic Medical Center, University of Amsterdam; Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam 1105 AZ, The Netherlands.
| | - Jeroen E J Guikema
- Department of Pathology, Academic Medical Center, University of Amsterdam; Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam 1105 AZ, The Netherlands.
| |
Collapse
|
9
|
Abstract
For nearly three decades, R loops have been closely linked with class switch recombination (CSR), the process that generates antibody isotypes and that occurs via a complex cascade initiated by transcription-coupled mutagenesis in switch recombination sequences. R loops form during transcription of switch recombination sequences in vitro and in vivo, and there is solid evidence that R loops are required for efficient class switching. The classical model of R loops posits that they boost mutation rates by generating stable and long tracts of single-stranded DNA that serve as the substrate for activation induced deaminase (AID), the enzyme that initiates the CSR reaction cascade by co-transcriptionally mutating ssDNA in switch recombination sequences. Though logical and compelling, this model has not been supported by in vivo evidence. Indeed, several reports suggest that R loops may not be involved in recruiting AID activity to switch regions, meaning that R loops probably serve other unanticipated roles in CSR. Here, I review the key findings in this field to date and propose hypotheses that could help towards elucidating the precise function of R loops in CSR.
Collapse
Affiliation(s)
- Rushad Pavri
- Research Institute of Molecular Pathology (IMP), Campus Vienna Biocenter-1, Vienna Biocenter, Vienna 1030, Austria.
| |
Collapse
|
10
|
Abbott RK, Silva M, Labuda J, Thayer M, Cain DW, Philbrook P, Sethumadhavan S, Hatfield S, Ohta A, Sitkovsky M. The GS Protein-coupled A2a Adenosine Receptor Controls T Cell Help in the Germinal Center. J Biol Chem 2016; 292:1211-1217. [PMID: 27974461 DOI: 10.1074/jbc.c116.764043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/07/2016] [Indexed: 11/06/2022] Open
Abstract
T follicular helper (TFH) cells have been shown to be critically required for the germinal center (GC) reaction where B cells undergo class switch recombination and clonal selection to generate high affinity neutralizing antibodies. However, detailed knowledge of the physiological cues within the GC microenvironment that regulate T cell help is limited. The cAMP-elevating, Gs protein-coupled A2a adenosine receptor (A2aR) is an evolutionarily conserved receptor that limits and redirects cellular immunity. However, the role of A2aR in humoral immunity and B cell differentiation is unknown. We hypothesized that the hypoxic microenvironment within the GC facilitates an extracellular adenosine-rich milieu, which serves to limit TFH frequency and function, and also promotes immunosuppressive T follicular regulatory cells (TFR). In support of this hypothesis, we found that following immunization, mice lacking A2aR (A2aRKO) exhibited a significant expansion of T follicular cells, as well as increases in TFH to TFR ratio, GC T cell frequency, GC B cell frequency, and class switching of GC B cells to IgG1. Transfer of CD4 T cells from A2aRKO or wild type donors into T cell-deficient hosts revealed that these increases were largely T cell-intrinsic. Finally, injection of A2aR agonist, CGS21680, following immunization suppressed T follicular differentiation, GC B cell frequency, and class switching of GC B cells to IgG1. Taken together, these observations point to a previously unappreciated role of GS protein-coupled A2aR in regulating humoral immunity, which may be pharmacologically targeted during vaccination or pathological states in which GC-derived autoantibodies contribute to the pathology.
Collapse
Affiliation(s)
- Robert K Abbott
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Murillo Silva
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Jasmine Labuda
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Molly Thayer
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Derek W Cain
- the Duke Human Vaccine Institute, Duke University, Durham, North Carolina 27710
| | - Phaethon Philbrook
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Shalini Sethumadhavan
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Stephen Hatfield
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Akio Ohta
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| | - Michail Sitkovsky
- From the New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, Massachusetts 02115 and
| |
Collapse
|