{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T02:50:32Z","timestamp":1791341432128,"version":"4.3.1"},"reference-count":27,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,3,29]],"date-time":"2021-03-29T00:00:00Z","timestamp":1616976000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>\n                    We have previously shown that conformational change in the \u03b2\n                    <jats:sub>2<\/jats:sub>\n                    -integrin is a very early activation marker that can be detected with fluorescent multimers of its ligand intercellular adhesion molecule (ICAM)-1 for rapid assessment of antigen-specific CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cells. In this study, we describe a modified protocol of this assay for sensitive detection of functional antigen-specific CD4\n                    <jats:sup>+<\/jats:sup>\n                    T cells using a monoclonal antibody (clone m24 Ab) specific for the open, high-affinity conformation of the \u03b2\n                    <jats:sub>2<\/jats:sub>\n                    -integrin. The kinetics of \u03b2\n                    <jats:sub>2<\/jats:sub>\n                    -integrin activation was different on CD4\n                    <jats:sup>+<\/jats:sup>\n                    and CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cells (several hours vs. few minutes, respectively); however, m24 Ab readily stained both cell types 4\u20136 h after antigen stimulation. With this protocol, we were able to monitor\n                    <jats:italic>ex vivo<\/jats:italic>\n                    effector and memory CD4\n                    <jats:sup>+<\/jats:sup>\n                    and CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cells specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cytomegalovirus (CMV), Epstein\u2013Barr virus (EBV), and hepatitis B virus (HBV) in whole blood or cryopreserved peripheral blood mononuclear cells (PBMCs) of infected or vaccinated individuals. By costaining \u03b2\n                    <jats:sub>2<\/jats:sub>\n                    -integrin with m24 and CD154 Abs, we assessed extremely low frequencies of polyfunctional CD4\n                    <jats:sup>+<\/jats:sup>\n                    T cell responses. The novel assay used in this study allows very sensitive and simultaneous screening of both CD4\n                    <jats:sup>+<\/jats:sup>\n                    and CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cell reactivities, with versatile applicability in clinical and vaccination studies.\n                  <\/jats:p>","DOI":"10.3389\/fimmu.2021.626308","type":"journal-article","created":{"date-parts":[[2021,3,29]],"date-time":"2021-03-29T08:02:55Z","timestamp":1617004975000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":11,"title":["Integrin Activation Enables Sensitive Detection of Functional CD4+ and CD8+ T Cells: Application to Characterize SARS-CoV-2 Immunity"],"prefix":"10.3389","volume":"12","author":[{"given":"Anna","family":"Sch\u00f6llhorn","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Juliane","family":"Schuhmacher","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luciana","family":"Besedovsky","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rolf","family":"Fendel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anja T. R.","family":"Jensen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan","family":"Stevanovi\u0107","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tanja","family":"Lange","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hans-Georg","family":"Rammensee","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan","family":"Born","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C\u00e9cile","family":"Gouttefangeas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stoyan","family":"Dimitrov","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2021,3,29]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"82","DOI":"10.1038\/25764","article-title":"Three-dimensional segregation of supramolecular activation clusters in T cells","volume":"395","author":"Monks","year":"1998","journal-title":"Nature."},{"key":"B2","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1146\/annurev-immunol-030409-101308","article-title":"Functional anatomy of T cell activation and synapse formation","volume":"28","author":"Fooksman","year":"2010","journal-title":"Annu Rev Immunol."},{"key":"B3","doi-asserted-by":"publisher","first-page":"5021","DOI":"10.4049\/jimmunol.1100646","article-title":"ICAM-1: getting a grip on leukocyte adhesion","volume":"186","author":"Long","year":"2011","journal-title":"J Immunol."},{"key":"B4","doi-asserted-by":"publisher","first-page":"1213","DOI":"10.4049\/jimmunol.1700495","article-title":"Not just an adhesion molecule: LFA-1 contact tunes the T lymphocyte program","volume":"199","author":"Verma","year":"2017","journal-title":"J Immunol."},{"key":"B5","doi-asserted-by":"publisher","first-page":"E5536","DOI":"10.1073\/pnas.1720714115","article-title":"Activated integrins identify functional antigen-specific CD8(+) T cells within minutes after antigen stimulation","volume":"115","author":"Dimitrov","year":"2018","journal-title":"Proc Natl Acad Sci USA."},{"key":"B6","doi-asserted-by":"publisher","first-page":"1855","DOI":"10.1007\/s00262-019-02365-1","article-title":"Adhering to adhesion: assessing integrin conformation to monitor T cells","volume":"68","author":"Gouttefangeas","year":"2019","journal-title":"Cancer Immunol Immunother."},{"key":"B7","doi-asserted-by":"publisher","first-page":"1113","DOI":"10.1038\/nm1293","article-title":"A live-cell assay to detect antigen-specific CD4+ T cells with diverse cytokine profiles","volume":"11","author":"Chattopadhyay","year":"2005","journal-title":"Nat Med."},{"key":"B8","doi-asserted-by":"publisher","first-page":"1118","DOI":"10.1038\/nm1292","article-title":"Direct access to CD4+ T cells specific for defined antigens according to CD154 expression","volume":"11","author":"Frentsch","year":"2005","journal-title":"Nat Med."},{"key":"B9","doi-asserted-by":"publisher","first-page":"65","DOI":"10.1111\/imr.12017","article-title":"How the immune system talks to itself: the varied role of synapses","volume":"251","author":"Xie","year":"2013","journal-title":"Immunol Rev."},{"key":"B10","doi-asserted-by":"publisher","first-page":"7796","DOI":"10.12688\/f1000research.7796.1","article-title":"Concerning immune synapses: a spatiotemporal timeline","volume":"5","author":"Ortega-Carrion","year":"2016","journal-title":"F1000Res."},{"key":"B11","doi-asserted-by":"publisher","first-page":"2333","DOI":"10.1073\/pnas.0307291101","article-title":"Activation of integrin \u03b2-subunit I-like domains by one-turn C-terminal \u03b1-helix deletions","volume":"101","author":"Yang","year":"2004","journal-title":"Proc Natl Acad Sci USA."},{"key":"B12","doi-asserted-by":"publisher","first-page":"475","DOI":"10.1083\/jcb.201406121","article-title":"F-actin flow drives affinity maturation and spatial organization of LFA-1 at the immunological synapseActin flow sustains LFA-1 activation at the IS","volume":"208","author":"Comrie","year":"2015","journal-title":"J Cell Biol."},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.21203\/rs.3.rs-27316\/v1","article-title":"Designing a therapeutic SARS-CoV-2 T-cell-inducing vaccine for high-risk patient groups","author":"Rammensee","year":"2020","journal-title":"Res Square. 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