{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T14:18:18Z","timestamp":1785421098631,"version":"3.56.0"},"posted":{"date-parts":[[2026,7,9]]},"group-title":"Immunology","reference-count":45,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T00:00:00Z","timestamp":1783555200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"id":[{"id":"https:\/\/ror.org\/04q9fhm49","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,7,9]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>\n                  CD4 T cells are essential for protective immunity against\n                  <jats:italic>Chlamydia<\/jats:italic>\n                  in the female reproductive tract (FRT), yet the characteristics of protective mucosal effector CD4 T cells remain poorly defined. We previously identified the transcription factor BHLHE40 as a key regulator of polyfunctional effector CD4 T cell differentiation during\n                  <jats:italic>Chlamydia<\/jats:italic>\n                  infection. Here, we identify the chemokine receptor CXCR6 as a marker of these protective T cells. Following intravaginal\n                  <jats:italic>Chlamydia muridarum<\/jats:italic>\n                  infection,\n                  <jats:italic>Bhlhe40<\/jats:italic>\n                  -deficient mice exhibited reduced frequencies of CXCR6\u207a CD4 T cells that correlated with impaired bacterial control. CXCR6 expression on T cells was associated with loss of stem-like features and acquisition of an effector phenotype. Compared with CXCR6\u207b cells, CXCR6\u207a CD4 T cells displayed enhanced proliferation and polyfunctionality by co-producing cytokines IFN-\u03b3, IL-17A, and GM-CSF. Although CXCR6 was dispensable for CD4 T cell homing to the FRT, it promoted localization to the infected epithelium and the emerging memory lymphoid clusters. Importantly, depletion of CXCR6\u207a CD4 T cells reduced polyfunctional effectors and impaired bacterial clearance. Collectively, these findings identify CXCR6 as a marker of protective polyfunctional CD4 T cells and implicate CXCR6-dependent tissue positioning as a key component of effective mucosal immunity, highlighting CXCR6 as a potential biomarker for Chlamydia vaccine development.\n                <\/jats:p>","DOI":"10.64898\/2026.07.05.736571","type":"posted-content","created":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T22:50:12Z","timestamp":1783637412000},"source":"Crossref","is-referenced-by-count":0,"title":["CXCR6 marks polyfunctional effector CD4 T cells required for anti-\n                  <i>Chlamydia<\/i>\n                  immunity in the female reproductive tract"],"prefix":"10.64898","author":[{"given":"Miguel A.B.","family":"Mercado","sequence":"first","affiliation":[{"name":"Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yejin","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiang","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lin-Xi","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026071306052260000_2026.07.05.736571v1.1","first-page":"e00541","article-title":"Innate IFN-\u03b3 Is Essential for Systemic Chlamydia muridarum Control in Mice, While CD4 T Cell-Dependent IFN-\u03b3 Production Is Highly Redundant in the Female Reproductive Tract","volume":"89","year":"2021","journal-title":"Infect. Immun"},{"key":"2026071306052260000_2026.07.05.736571v1.2","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1010333"},{"key":"2026071306052260000_2026.07.05.736571v1.3","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1011914"},{"key":"2026071306052260000_2026.07.05.736571v1.4","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00984-10"},{"key":"2026071306052260000_2026.07.05.736571v1.5","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0076664"},{"key":"2026071306052260000_2026.07.05.736571v1.6","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1111\/aji.12171","article-title":"IL-23 Induces IL-22 and IL-17 Production in Response to Chlamydia muridarum Genital Tract Infection, but the Absence of these Cytokines does not Influence Disease Pathogenesis","volume":"70","year":"2013","journal-title":"American Journal of Reproductive Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.7","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.01378-15"},{"key":"2026071306052260000_2026.07.05.736571v1.8","doi-asserted-by":"publisher","DOI":"10.1016\/j.imlet.2018.08.002"},{"key":"2026071306052260000_2026.07.05.736571v1.9","doi-asserted-by":"crossref","first-page":"e1011983","DOI":"10.1371\/journal.ppat.1011983","article-title":"BHLHE40 drives protective polyfunctional CD4 T cell differentiation in the female reproductive tract against Chlamydia","volume":"20","year":"2024","journal-title":"PLOS Pathogens"},{"key":"2026071306052260000_2026.07.05.736571v1.10","unstructured":"CDC Sexually Transmitted Infections Surveillance, 2024 (Provisional). STI Statistics (2025).at <https:\/\/www.cdc.gov\/sti-statistics\/annual\/index.html>"},{"key":"2026071306052260000_2026.07.05.736571v1.11","doi-asserted-by":"publisher","DOI":"10.1016\/j.vaccine.2013.01.024"},{"key":"2026071306052260000_2026.07.05.736571v1.12","doi-asserted-by":"publisher","DOI":"10.1016\/j.vaccine.2017.10.075"},{"key":"2026071306052260000_2026.07.05.736571v1.13","doi-asserted-by":"publisher","DOI":"10.1038\/ni.f.213"},{"key":"2026071306052260000_2026.07.05.736571v1.14","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1038\/mi.2010.58","article-title":"CXCR3 and CCR5 are both required for T cell-mediated protection against C. trachomatis infection in the murine genital mucosa","volume":"4","year":"2011","journal-title":"Mucosal Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.15","doi-asserted-by":"crossref","first-page":"4284","DOI":"10.4049\/jimmunol.1303238","article-title":"Integrin \u03b14\u03b21 Is Necessary for CD4+ T Cell\u2013Mediated Protection against Genital Chlamydia trachomatis Infection","volume":"192","year":"2014","journal-title":"The Journal of Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.16","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.1601314"},{"key":"2026071306052260000_2026.07.05.736571v1.17","doi-asserted-by":"publisher","DOI":"10.1038\/79738"},{"key":"2026071306052260000_2026.07.05.736571v1.18","doi-asserted-by":"publisher","DOI":"10.1172\/JCI11902"},{"key":"2026071306052260000_2026.07.05.736571v1.19","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2567.2007.02603.x"},{"key":"2026071306052260000_2026.07.05.736571v1.20","doi-asserted-by":"crossref","unstructured":"Hou, L. & Yuki, K . CCR6 and CXCR6 Identify the Th17 Cells With Cytotoxicity in Experimental Autoimmune Encephalomyelitis. Frontiers in Immunology 13, (2022).","DOI":"10.3389\/fimmu.2022.819224"},{"key":"2026071306052260000_2026.07.05.736571v1.21","doi-asserted-by":"publisher","DOI":"10.1084\/jem.20181308"},{"key":"2026071306052260000_2026.07.05.736571v1.22","doi-asserted-by":"crossref","first-page":"2921","DOI":"10.1016\/j.celrep.2017.08.078","article-title":"Human Tissue-Resident Memory T Cells Are Defined by Core Transcriptional and Functional Signatures in Lymphoid and Mucosal Sites","volume":"20","year":"2017","journal-title":"Cell Reports"},{"key":"2026071306052260000_2026.07.05.736571v1.23","doi-asserted-by":"crossref","first-page":"2845","DOI":"10.4049\/jimmunol.1700914","article-title":"A Chlamydia-Specific TCR-Transgenic Mouse Demonstrates Th1 Polyfunctionality with Enhanced Effector Function","volume":"199","year":"2017","journal-title":"The Journal of Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.24","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1003707"},{"key":"2026071306052260000_2026.07.05.736571v1.25","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0042403"},{"key":"2026071306052260000_2026.07.05.736571v1.26","doi-asserted-by":"crossref","first-page":"2308","DOI":"10.4049\/jimmunol.1901396","article-title":"Efficient CRISPR\/Cas9 Gene Editing in Uncultured Naive Mouse T Cells for In Vivo Studies","volume":"204","year":"2020","journal-title":"The Journal of Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.27","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1711356115"},{"key":"2026071306052260000_2026.07.05.736571v1.28","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.72.7.3951-3960.2004"},{"key":"2026071306052260000_2026.07.05.736571v1.29","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-017-02223-z"},{"key":"2026071306052260000_2026.07.05.736571v1.30","doi-asserted-by":"publisher","DOI":"10.1038\/ni.1953"},{"key":"2026071306052260000_2026.07.05.736571v1.31","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.68.5.2870-2879.2000"},{"key":"2026071306052260000_2026.07.05.736571v1.32","doi-asserted-by":"crossref","unstructured":"Ashhurst, A. S. et al. CXCR6-Deficiency Improves the Control of Pulmonary Mycobacterium tuberculosis and Influenza Infection Independent of T-Lymphocyte Recruitment to the Lungs. Front. Immunol. 10, (2019).","DOI":"10.3389\/fimmu.2019.00339"},{"key":"2026071306052260000_2026.07.05.736571v1.33","doi-asserted-by":"publisher","DOI":"10.1093\/infdis\/jiu281"},{"key":"2026071306052260000_2026.07.05.736571v1.34","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0097701"},{"key":"2026071306052260000_2026.07.05.736571v1.35","first-page":"4965","article-title":"Th1\/Th17 T cell Tissue-Resident Immunity Increases Protection, But Is Not Required in a Vaccine Strategy Against Genital Infection With Chlamydia trachomatis","volume":"12","year":"2021","journal-title":"Frontiers in Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.36","doi-asserted-by":"crossref","unstructured":"Yount, K. S. , et al. T cell signatures associated with reduced Chlamydia trachomatis reinfection in a highly exposed cohort. JCI Insight 10, (2025).","DOI":"10.1172\/jci.insight.189388"},{"key":"2026071306052260000_2026.07.05.736571v1.37","doi-asserted-by":"crossref","first-page":"3344","DOI":"10.4049\/jimmunol.158.7.3344","article-title":"Immunity to Chlamydia trachomatis is mediated by T helper 1 cells through IFN-gamma-dependent and -independent pathways","volume":"158","year":"1997","journal-title":"The Journal of Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.38","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00161-13"},{"key":"2026071306052260000_2026.07.05.736571v1.39","doi-asserted-by":"crossref","unstructured":"Shi, S. et al. CXCR6 defines therapeutic subtypes of CD4+ cytotoxic T cell lineage for adoptive cell transfer therapy in pediatric B cell acute lymphoblastic leukemia. International Immunopharmacology 132, 111972 (2024).","DOI":"10.1016\/j.intimp.2024.111972"},{"key":"2026071306052260000_2026.07.05.736571v1.40","doi-asserted-by":"publisher","DOI":"10.1016\/j.cell.2021.07.015"},{"key":"2026071306052260000_2026.07.05.736571v1.41","doi-asserted-by":"crossref","first-page":"328","DOI":"10.4049\/jimmunol.2300131","article-title":"Cytotoxic CD4+ T Cells Are Induced during Infection with Chlamydia trachomatis","volume":"213","year":"2024","journal-title":"The Journal of Immunology"},{"key":"2026071306052260000_2026.07.05.736571v1.42","doi-asserted-by":"crossref","unstructured":"Alexander, K. M. et al. CXCR4 and CXCR6 dually limit T cell entry into the polyomavirus-infected brain. J Neuroinflammation 22, 169 (2025).","DOI":"10.1186\/s12974-025-03496-2"},{"key":"2026071306052260000_2026.07.05.736571v1.43","doi-asserted-by":"publisher","DOI":"10.4049\/jimmunol.2300355"},{"key":"2026071306052260000_2026.07.05.736571v1.44","doi-asserted-by":"crossref","first-page":"vkaf219","DOI":"10.1093\/jimmun\/vkaf219","article-title":"CXCR6 promotes dermal CD8+ T cell survival and transition to long-term tissue residence","volume":"215","year":"2026","journal-title":"J Immunol"},{"key":"2026071306052260000_2026.07.05.736571v1.45","doi-asserted-by":"crossref","unstructured":"Rosen, S. F. et al. Single-cell RNA transcriptome analysis of CNS immune cells reveals CXCL16\/CXCR6 as maintenance factors for tissue-resident T cells that drive synapse elimination. Genome Med 14, 108 (2022).","DOI":"10.1186\/s13073-022-01111-0"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.07.05.736571","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T13:05:32Z","timestamp":1783947932000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.07.05.736571"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,9]]},"references-count":45,"URL":"https:\/\/doi.org\/10.64898\/2026.07.05.736571","relation":{},"subject":[],"published":{"date-parts":[[2026,7,9]]},"subtype":"preprint"}}