biostudies-literatureGossez MEuropean Research CouncilAgence Nationale de la Recherche (French National Research Agency)3030https://www.ebi.ac.uk/biostudies/studies/S-EPMC11953283biostudies-literatureUnknown16(1)Sepsis, a leading cause of death in intensive care units, is associated with immune alterations that increase the patients' risk of secondary infections and mortality, so better understandings of the pathophysiology of sepsis-induced immunosuppression is essential for the development of therapeutic strategies. In a murine model of sepsis that recapitulates immune alterations observed in patients, here we demonstrate that PD-L1⁺CD44⁺B220^LowCD138⁺IgM⁺ regulatory plasma cells are induced in spleen and regulate ex vivo proliferation and IFNɣ secretion induced by stimulation of T splenocytes. This effect is mediated both by cell-cell contact through increased PD-L1 expression on plasma cells and by production of a soluble factor. These obseNature communicationsPD-L1<sup>+</sup> plasma cells suppress T lymphocyte responses in patients with sepsis and mouse sepsis models.PMC11953283ANR-20-CE92-0024-01616986Malcus CGossez MPy BFPescarmona RCarre CBequet FRichard JCBoussaha IGardiner DCaruso LRaychaudhuri AMartin OTissot SOriol GTruc CKoenig NCrozon-Clauzel JTextoris JBounab YHuriaux LDailler FJourdan CMallet FRICO study groupDebord-Peguet SGregoire AKandara KREALISM study groupMommert MBitker LGatel JGrosjean CUberti TBuisson MRiffaud CBerger SBDevigne BDe Monfort AThaunat OVallin HCoudereau RMaucort-Boulch DGenin CFlorin KBrengel-Pesce KDelignette MCLopez JMoriceau FConti FGallet-Gorius EMeuret PMacnamara AMoriniere JPeleraux AVillard MHengy BGillespie IToetsch SAugris-Mathieu CCollus MArnal SDelsuc CLouis KArgaud LTabone OCanard BRimmele TMezidi MBenatir FTran TBen-Amor ACerro VDargent AMicoud ELepape ASchrevel CMouscaz YMoucadel VItah LBrajon FSmylie RPerret MLepage MDelwarde BJadaud CMonneret GMonard CGough PJSimon MPayrard SPachot ARol MLOrtillon MBaboi LReynier FMeunier BMistretta MAshton TPeronnet ETan LBertin-Maghit MFugier IPanel NGorse IGarcon NPaidassai HJallades LLeissner PSapay NCejka JCRahali NFaure ACortez PCour MDefrance TFraisse LMarcotte GBlein SBertin-Maghit ABouffard YDavidson JLeray VVedrine CGroussaud MBecker JLukaszewicz ACMatray MCheynet VGirardot TFayolle-Pivot LBer CEWallet FDeleat-Besson RBignet LCourcol LGuyard CNoailles LLavocat FBayle FCerrato EQuemeneur LBellocq ASStevic NMarcos JYBoibieux ABertrand PJFabri AVandermoeten AZadam AVigneron CGriffiths AGarnier LProvent MFloccard BPoitevin-Later FGuichard AVenet FTipple CLombard CfalsePD-L1<sup>+</sup> plasma cells suppress T lymphocyte responses in patients with sepsis and mouse sepsis models.Sepsis, a leading cause of death in intensive care units, is associated with immune alterations that increase the patients' risk of secondary infections and mortality, so better understandings of the pathophysiology of sepsis-induced immunosuppression is essential for the development of therapeutic strategies. In a murine model of sepsis that recapitulates immune alterations observed in patients, here we demonstrate that PD-L1⁺CD44⁺B220^LowCD138⁺IgM⁺ regulatory plasma cells are induced in spleen and regulate ex vivo proliferation and IFNɣ secretion induced by stimulation of T splenocytes. This effect is mediated both by cell-cell contact through increased PD-L1 expression on plasma cells and by production of a soluble factor. These obse2025-01-01T00:00:00Z2025 Mar2026-06-02T12:00:18.167Z2026-04-18T03:10:52.128ZS-EPMC119532834015539410.1038/s41467-025-57706-9