Pulmonary Microvascular Endothelial Antigen Presentation Activates Resident CD8⁺ T Cells to Restrain Influenza Lung Injury

Pulmonary Microvascular Endothelial Antigen Presentation Activates Resident CD8⁺ T Cells to Restrain Influenza Lung Injury | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Pulmonary Microvascular Endothelial Antigen Presentation Activates Resident CD8⁺ T Cells to Restrain Influenza Lung Injury Lianghui Zhang, Yuanyun Ao, Kamal Bagale, Sophia Hu, Ahmed Mostafa, and 16 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7796497/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract The remaining unacceptably high mortality of influenza-induced acute respiratory distress syndrome underscores the urgent need to identify key cellular drivers of host responses. Endothelial cells (ECs) are increasingly recognized for their immunomodulatory roles, but whether they function as antigen-presenting cells (APCs) following respiratory viral infection remains unknown. Here, we show that influenza A virus H1N1 restrictively infects pulmonary microvascular ECs (PMVECs) during late-stage acute lung injury, triggering robust MHC class I (MHC-I) upregulation in vitro, in vivo, and in ex vivo human precision-cut lung slices. Infected PMVECs present H1N1 antigens via MHC-I and co-stimulatory CD40 to lung-resident CD8⁺ T cells, driving their proliferation and effector function (Granzyme B, IFNγ) to promote viral clearance and resolve inflammation. This process is IFNγ-dependent and STAT1-regulated, forming a positive feedback loop that enhances PMVEC antigen presentation and CD8⁺ T cells activation. By contrast, the emerging H5N1 (A/Texas/37/2024) infect pulmonary ECs earlier and more broadly but elicits weaker pulmonary EC-driven CD8 + T cell responses, potentially contributing to its higher pathogenicity. These findings reveal PMVECs as active APCs in antiviral defense and highlight new avenues for immunotherapeutic intervention. Biological sciences/Immunology/Infectious diseases/Influenza virus Health sciences/Diseases/Infectious diseases/Influenza virus Biological sciences/Immunology/Adaptive immunity/Cellular immunity/Antigen presentation Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementalinformationfinal.docx Supplemental methods Extendeddata12.16.2025.pdf Extended Data Figures 1-10 Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7796497","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":570060012,"identity":"2bc0cc50-6584-4990-9b52-f95b55ccb050","order_by":0,"name":"Lianghui 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Injury","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature 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Endothelial cells (ECs) are increasingly recognized for their immunomodulatory roles, but whether they function as antigen-presenting cells (APCs) following respiratory viral infection remains unknown. Here, we show that influenza A virus H1N1 restrictively infects pulmonary microvascular ECs (PMVECs) during late-stage acute lung injury, triggering robust MHC class I (MHC-I) upregulation in vitro, in vivo, and in ex vivo human precision-cut lung slices. Infected PMVECs present H1N1 antigens via MHC-I and co-stimulatory CD40 to lung-resident CD8⁺ T cells, driving their proliferation and effector function (Granzyme B, IFNγ) to promote viral clearance and resolve inflammation. This process is IFNγ-dependent and STAT1-regulated, forming a positive feedback loop that enhances PMVEC antigen presentation and CD8⁺ T cells activation. By contrast, the emerging H5N1 (A/Texas/37/2024) infect pulmonary ECs earlier and more broadly but elicits weaker pulmonary EC-driven CD8\u0026thinsp;+\u0026thinsp;T cell responses, potentially contributing to its higher pathogenicity. These findings reveal PMVECs as active APCs in antiviral defense and highlight new avenues for immunotherapeutic intervention.\u003c/p\u003e","manuscriptTitle":"Pulmonary Microvascular Endothelial Antigen Presentation Activates Resident CD8⁺ T Cells to Restrain Influenza Lung Injury","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-08 06:26:52","doi":"10.21203/rs.3.rs-7796497/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"e73b8ea0-18f7-4e6c-a4f1-8a96f55c5a39","owner":[],"postedDate":"January 8th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":60657119,"name":"Biological sciences/Immunology/Infectious diseases/Influenza virus"},{"id":60657120,"name":"Health sciences/Diseases/Infectious diseases/Influenza virus"},{"id":60657121,"name":"Biological sciences/Immunology/Adaptive immunity/Cellular immunity/Antigen presentation"}],"tags":[],"updatedAt":"2026-05-05T04:10:18+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-08 06:26:52","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7796497","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7796497","identity":"rs-7796497","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}