title: Cognate antigen stimulation generates potent CD8(+) inflammatory effector T cells.
abstract: Inflammatory reactions are believed to be triggered by innate signals and have a major protective role by recruiting innate immunity cells, favoring lymphocyte activation and differentiation, and thus contributing to the sequestration and elimination of the injurious stimuli. Although certain lymphocyte types such as TH17 cells co-participate in inflammatory reactions, their generation from the naïve pool requires the pre-existence of an inflammatory milieu. In this context, inflammation is always regarded as beginning with an innate response that may be eventually perpetuated and amplified by certain lymphocyte types. In contrast, we here show that even in sterile immunizations or in MyD88-deficient mice, CD8 T cells produce a burst of pro-inflammatory cytokines and chemokines. These functions follow opposite rules to the classic CD8 effector functions since they are generated prior to cell expansion and decline before antigen elimination. As few as 56 CD8(+) inflammatory effector cells in a lymph node can mobilize 10(7) cells in 24 h, including lymphocytes, natural killer cells, and several accessory cell types involved in inflammatory reactions. Thus, although inflammation modulates cognate responses, CD8 cognate responses also initiate local inflammatory reactions.
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Hsueh-Cheng
authors.initials: HC
authors.lastname: Sung
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Sara
authors.initials: S
authors.lastname: Lemos
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ribeiro-Santos
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Kateryna
authors.initials: K
authors.lastname: Kozyrytska
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Florence
authors.initials: F
authors.lastname: Vasseur
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Legrand
authors.affiliation: Faculté de Médecine, U1002, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Alain
authors.initials: A
authors.lastname: Charbit
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: Benedita
authors.initials: B
authors.lastname: Rocha
authors.affiliation: Faculté de Médecine, U1020, Université Paris-Descartes, INSERM , Paris , France.
authors.forename: César
authors.initials: C
authors.lastname: Evaristo
keywords: CD8 T cells; effector functions; immune responses; lymph-node shut-down-phase; lymphocyte trapping