T Cells Regulate Peripheral Naive Mature B Cell Survival by Cell −Cell Contact Mediated through SLAMF6 and SAP This information is current as Lihi Radomir, Sivan Cohen, Matthias P. Kramer, Eszter of September 23, 2021. Bakos, Hadas Lewinsky, Avital Barak, Ziv Porat, Richard Bucala, Polina Stepensky, Shirly Becker-Herman and Idit Shachar J Immunol 2017; 199:2745-2757; Prepublished online 13 September 2017; Downloaded from doi: 10.4049/jimmunol.1700557 http://www.jimmunol.org/content/199/8/2745 Supplementary http://www.jimmunol.org/content/suppl/2017/09/13/jimmunol.170055 http://www.jimmunol.org/ Material 7.DCSupplemental References This article cites 46 articles, 16 of which you can access for free at: http://www.jimmunol.org/content/199/8/2745.full#ref-list-1 Why The JI? Submit online. by guest on September 23, 2021 • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2017 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology T Cells Regulate Peripheral Naive Mature B Cell Survival by Cell–Cell Contact Mediated through SLAMF6 and SAP Lihi Radomir,*,1 Sivan Cohen,*,1 Matthias P. Kramer,* Eszter Bakos,* Hadas Lewinsky,* Avital Barak,* Ziv Porat,† Richard Bucala,‡ Polina Stepensky,x Shirly Becker-Herman,* and Idit Shachar* The control of lymphoid homeostasis is the result of a very fine balance between lymphocyte production, proliferation, and apoptosis. In this study, we focused on the role of T cells in the maintenance/survival of the mature naive peripheral B cell population. We show that naive B and T cells interact via the signaling lymphocyte activation molecule (SLAM) family receptor, SLAMF6. This interaction induces cell type–specific signals in both cell types, mediated by the SLAM-associated protein (SAP) family of adaptors. This signaling results in an upregulation of the expression of the cytokine migration inhibitory factor in the T cells and augmented expression of its receptor CD74 on the B cell counterparts, consequently enhancing B cell survival. Downloaded from Furthermore, in X-linked lymphoproliferative disease patients, SAP deficiency reduces CD74 expression, resulting in the pertur- bation of B cell maintenance from the naive stage. Thus, naive T cells regulate B cell survival in a SLAMF6- and SAP-dependent manner. The Journal of Immunology, 2017, 199: 2745–2757. he survival of peripheral naive mature B cells is dependent is modified by the addition of chondroitin sulfate, and this form of on three key cascades: 1) BCR tonic signals (e.g., Iga and CD74 is expressed on the surface of APCs (including monocytes and http://www.jimmunol.org/ T Syk) (1, 2); 2) the B cell activating factor receptor, which B cells) and epithelial cells (7). It was previously shown that mac- binds the B cell activating factor, belonging to the TNF family (the rophage MIF binds to the CD74 extracellular domain, a process that B cell activating factor is also known as BLyS/TALL-1/THANK/ results in the initiation of a signaling pathway in these cells (8). zTNF4) (3); and 3) CD74 (invariant chain) expressed on B cells, CD74 stimulation by MIF induces a signaling cascade leading to and its cognate ligand, macrophage migration inhibitory factor NF-kB activation, as well as transcription of genes that regulate (MIF), which is secreted by almost all cell types. These pathways the entry of the stimulated B cells into the S phase, an increase in have complementary roles in B cell survival (4, 5). DNA synthesis, cell division, and augmented expression of anti- CD74 is a type II integral membrane protein that acts as a chaperone apoptotic proteins (5, 9, 10). The CD74 receptor induces a similar by guest on September 23, 2021 for MHC class II protein expression (6). A small proportion of CD74 survival cascade in oncogenically transformed cells derived from chronic lymphocytic leukemia (CLL) patients (11). To define the molecules whose expression is modulated by CD74 to regulate *Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel; †Department of Biological Services, Weizmann Institute of Science, Rehovot 76100, CLL cell survival, we previously screened for CD74 target genes. Israel; ‡Department of Internal Medicine, Yale University School of Medicine, New One molecule, whose expression was strongly upregulated by x Haven, CT 06520; and Pediatric Hematology-Oncology and Bone Marrow Transplan- CD74 activation, is signaling lymphocyte activation molecule tation Unit, Hadassah Hebrew University Medical Center, Jerusalem 91120, Israel 1 (SLAM)F5 (CD84), a member of the SLAM Ig superfamily (12). L.R. and S.C. contributed equally to this work. The SLAM family of receptors includes homophilic and het- ORCIDs: 0000-0002-0289-5261 (M.P.K.); 0000-0003-3059-181X (Z.P.); 0000-0003- 0004-6159 (I.S.). erophilic receptors that modulate the behavior of immune cells (13– 15). These receptors share a common ectodomain organization: a Received for publication April 19, 2017. Accepted for publication August 10, 2017. membrane-proximal Ig-like constant domain, and a membrane- This work was supported in part by the Binational Science Foundation, the Cooper- ation Program in Cancer Research of the Deutsches Krebsforschungszentrum distal Ig variable domain that is responsible for ligand recognition. and Israel’s Ministry of Science, Technology and Space, the Quinquin Foundation, and SLAM receptors interact with SLAM-associated protein (SAP)–related the Rubenstein Charitable Foundation. I.S. is the incumbent of the Dr. Morton and A. Kleiman Professorial Chair. molecules, a group of SRC homology 2 (SH2) domain adaptors. The SAP family is comprised of three members: SAP, Ewing’s L.R., S.C., and M.P.K. designed research, performed research, analyzed data, and wrote the paper; E.B., L.R., H.L., A.B., and Z.P. designed research, performed sarcoma–associated transcript 2 (EAT-2), and, in rodents, EAT-2– research, and analyzed data; R.B. and P.S. provided essential reagents and wrote related transducer (16, 17). SAP controls signal transduction path- the paper; S.B.-H. designed research and analyzed data; and I.S. designed research, analyzed data, and wrote the paper. ways downstream of the SLAM family receptors, and it is a key Address correspondence and reprint requests to Dr. Idit Shachar, Department of regulator of normal immune function in T, NK, and NKT cells (15, Immunology, Weizmann Institute of Science, Herzl Street, Rehovot 76100, Israel. 18). However, B cells do not express SAP (19), and EAT-2 was E-mail address: [email protected] suggested to serve as its functional homolog in these cells (20, 21). The online version of this article contains supplemental material. The SLAM receptors and their adaptor molecules were shown to Abbreviations used in this article: 7-AAD, 7-aminoactinomycin D; CLL, chronic be required for germinal center development and humoral memory lymphocytic leukemia; EAT-2, Ewing’s sarcoma–associated transcript 2; MIF, macro- phage migration inhibitory factor; PB, peripheral blood; SAP, SLAM-associated (22–24). However, their role in naive B cell maintenance has not protein; SH2, SRC homology 2; siRNA, small interfering RNA; SLAM, signaling been assessed in detail. Lymphocyte populations derived from lymphocyte activation molecule; WT, wild-type; XLP, X-linked lymphoproliferative SAP-deficient mice are grossly normal, although occasional mu- disease. tant animals exhibit a higher percentage of T and NK cells, as well Copyright Ó 2017 by The American Association of Immunologists, Inc. 0022-1767/17/$35.00 as a lower percentage of B cells in the spleen (25). www.jimmunol.org/cgi/doi/10.4049/jimmunol.1700557 2746 CD4+ T CELLS REGULATE NAIVE B CELL SURVIVAL In the present study, we hypothesized that the SLAM family EAT-2 (ON-TARGET plus SMART pool) and negative control siRNA (ON- might be involved in the regulation of naive B cell survival in the TARGETplus nontargeting pool) (Dharmacon). cross-talk between naive B and naive T cells in an Ag-independent Real-time RT-PCR analysis environment. Our findings demonstrate that interaction of B cells with T cells in a SLAMF6/SAP-mediated manner upregulates RNA extraction and quantitative RT-PCR were performed as previously described (31). Primers are summarized in Table I. CD74 cell surface expression on B cells, inducing their survival in vitro and in vivo. This study highlights a crucial role of SAP Stimulation of murine B cells with CD74 expression on T cells in regulating B cell survival and provides Activation of CD74 was performed as previously described (9). new insights into the requirements for cell collaboration during homeostasis. Blocking SLAMF6 on human B cells Human B cells (1 3 107) were incubated in the presence of 20 mg/ml monoclonal anti–NTB-A Ab (clone NT-7) or mouse IgG1 k isotype control Materials and Methods Abs (BioLegend), as previously described (32). Mice Coculture C57BL/6, CD74-deficient (26), MIF-deficient (27), SLAMF5-deficient (24), SH2D1A (SAP)-deficient (25) SLAMF6-deficient (28), and SLAMF1- Coculture of murine primary B and T cells was performed in 24-well plates with 10% FCS (w/v) Iscove’s medium. Transwell experiments were performed deficient mice (29) were used in this study. All animal procedures were m approved by the Animal Research Committee at the Weizmann Institute of in 24-well plates containing an insert with a 5- m pore polycarbonate Science.