{"doi":"10.17615/5jbx-zw12","title":"Francisella tularensis Elicits IL-10 via a PGE2-Inducible Factor, to Drive Macrophage MARCH1 Expression and Class II Down-Regulation","abstract":"Francisella tularensis is a bacterial pathogen that uses host-derived PGE2 to subvert the host's adaptive immune responses in multiple ways. Francisella-induced PGE2 acts directly on CD4 T cells to blunt production of IFN-γ. Francisella-induced PGE2 can also elicit production of a >10 kDa soluble host factor termed FTMØSN (F. tularensis macrophage supernatant), which acts on IFN-γ pre-activated MØ to down-regulate MHC class II expression via a ubiquitin-dependent mechanism, blocking antigen presentation to CD4 T cells. Here, we report that FTMØSN-induced down-regulation of MØ class II is the result of the induction of MARCH1, and that MØ expressing MARCH1 “resistant” class II molecules are resistant to FTMØSN-induced class II down-regulation. Since PGE2 can induce IL-10 production and IL-10 is the only reported cytokine able to induce MARCH1 expression in monocytes and dendritic cells, these findings suggested that IL-10 is the active factor in FTMØSN. However, use of IL-10 knockout MØ established that IL-10 is not the active factor in FTMØSN, but rather that Francisella-elicited PGE2 drives production of a >10 kDa host factor distinct from IL-10. This factor then drives MØ IL-10 production to induce MARCH1 expression and the resultant class II down-regulation. Since many human pathogens such as Salmonella typhi, Mycobacterium tuberculosis and Legionella pneumophila also induce production of host PGE2, these results suggest that a yet-to-be-identified PGE2-inducible host factor capable of inducing IL-10 is central to the immune evasion mechanisms of multiple important human pathogens.","journal":"UNC Libraries","year":2020,"id":142078,"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":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.949,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":608043,"name":"James R. Drake","orcid":"0000-0001-7675-6443","position":1,"is_corresponding":false},{"id":476699,"name":"Jonathan A. Harton","orcid":"0000-0002-0350-1877","position":2,"is_corresponding":false},{"id":285556,"name":"Danielle Hunt","orcid":"0000-0002-3557-4915","position":3,"is_corresponding":false},{"id":304062,"name":"Paul A. Roche","orcid":"0000-0002-8949-9172","position":4,"is_corresponding":false},{"id":608669,"name":"Karis A. Weih","orcid":null,"position":5,"is_corresponding":false},{"id":531436,"name":"Justin E. Wilson","orcid":"0000-0002-2803-3280","position":6,"is_corresponding":false},{"id":379243,"name":"Satoshi Ishido","orcid":"0000-0001-5893-3354","position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:17:27.861239Z","pmid":null,"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":[]}