{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,6,13]],"date-time":"2026-06-13T20:48:31Z","timestamp":1781383711751,"version":"3.54.1"},"posted":{"date-parts":[[2025,4,16]]},"group-title":"Immunology","reference-count":39,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2025,4,16]],"date-time":"2025-04-16T00:00:00Z","timestamp":1744761600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2025,12,2]]},"abstract":"<jats:title>SUMMARY PARAGRAPH<\/jats:title>\n                <jats:p>\n                  An effective immune system must sample and appreciate healthy-self identity to prevent autoimmunity and to contrast to pathogenic insults\n                  <jats:sup>1\u20133<\/jats:sup>\n                  . Self-proteins are presented to T cells in the thymus during immune cell development\n                  <jats:sup>2,3<\/jats:sup>\n                  , and must be presented throughout the body to both maintain regulatory T cell populations\n                  <jats:sup>4\u20136<\/jats:sup>\n                  and provide a tonic signal to maintain conventional T cells over time\n                  <jats:sup>7\u20139<\/jats:sup>\n                  . The ready observations of continuous apoptosis in some organs together with the ingestion of that material by myeloid populations has led to a conventional understanding of ongoing cell-death as a major source of self-antigens\n                  <jats:sup>10<\/jats:sup>\n                  , complemented in some situations by uptake of free-floating cell-derived vesicles. Here, we used a series of companion imaging and vesicular labeling technologies to reveal an alternate process undertaken by macrophages that results in non-destructive and direct sampling of living cells. The process requires cell-cell contact, does not require caspase activation, and takes place via a trogocytosis-like stretching of the target cell into the macrophage, leading to the generation of submicron-sized vesicles containing cytoplasm. Using a high-dimensional flow-based method for labeling vesicles ingested under this versus other conditions, we find that live-sampled material is distinctly processed, is poorly subject to fusion with lysosomes, and produces ensuing differential effects on the presentation of those to CD4 versus CD8 T cells. Disrupting this trafficking by redirecting antigen to the lysosome significantly reduced the associated macrophage-mediated priming of CD8 T cells. This demonstrates an important and substantial sampling of living cells by the immune system, with clear consequences for maintaining the border of immunity.\n                <\/jats:p>","DOI":"10.1101\/2025.04.10.648051","type":"posted-content","created":{"date-parts":[[2025,4,19]],"date-time":"2025-04-19T06:05:17Z","timestamp":1745042717000},"source":"Crossref","is-referenced-by-count":2,"title":["Submicron-Sampling of Living Cells by Macrophages"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1612-1862","authenticated-orcid":false,"given":"Amy C.","family":"Fan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9225-9516","authenticated-orcid":false,"given":"Rukman","family":"Thota","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2243-5446","authenticated-orcid":false,"given":"Nina","family":"Serwas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5409-8635","authenticated-orcid":false,"given":"Vivasvan S.","family":"Vykunta","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0169-7439","authenticated-orcid":false,"given":"Kyle","family":"Marchuk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3658-8363","authenticated-orcid":false,"given":"Megan K.","family":"Ruhland","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lauren","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Grace","family":"Johnson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5205-6143","authenticated-orcid":false,"given":"Austin","family":"Edwards","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7915-3533","authenticated-orcid":false,"given":"Matthew F.","family":"Krummel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2025120408300818000_2025.04.10.648051v2.1","doi-asserted-by":"crossref","unstructured":"Medawar, P.B. 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