{"doi":"10.1101/2025.04.10.648051","title":"Submicron-Sampling of Living Cells by Macrophages","abstract":"SUMMARY PARAGRAPH An effective immune system must sample and appreciate healthy-self identity to prevent autoimmunity and to contrast to pathogenic insults 1–3 . Self-proteins are presented to T cells in the thymus during immune cell development 2,3 , and must be presented throughout the body to both maintain regulatory T cell populations 4–6 and provide a tonic signal to maintain conventional T cells over time 7–9 . 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 10 , 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.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2025,"id":556158,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":2,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9431,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":933086,"name":"Rukman R. Thota","orcid":"0000-0002-9225-9516","position":1,"is_corresponding":false},{"id":240179,"name":"Nina K. Serwas","orcid":"0000-0003-2243-5446","position":2,"is_corresponding":false},{"id":805859,"name":"Vivasvan S. Vykunta","orcid":"0000-0002-5409-8635","position":3,"is_corresponding":false},{"id":902628,"name":"Kyle Marchuk","orcid":"0000-0003-0169-7439","position":4,"is_corresponding":false},{"id":240173,"name":"Megan K. Ruhland","orcid":"0000-0003-3658-8363","position":5,"is_corresponding":false},{"id":750047,"name":"Lauren Liu","orcid":"0009-0003-2329-1867","position":6,"is_corresponding":false},{"id":903940,"name":"Grace Johnson","orcid":"0000-0002-1776-4977","position":7,"is_corresponding":false},{"id":625662,"name":"Austin Edwards","orcid":"0000-0001-5205-6143","position":8,"is_corresponding":false},{"id":240181,"name":"Matthew F. Krummel","orcid":"0000-0001-7915-3533","position":9,"is_corresponding":false},{"id":640062,"name":"Amy C. Fan","orcid":"0000-0003-1612-1862","position":0,"is_corresponding":true}],"reference_count":29,"raw_metadata":null,"created_at":"2026-07-19T02:55:08.896385Z","pmid":"41377517","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}