Dendritic cells and CD28 costimulation are required to sustain virus-specific CD8+ T cell responses during the effector phase in vivo.

摘要: Although much is known about the initiation of immune responses, less what controls effector phase. CD8(+) T cell responses are believed to be programmed in lymph nodes during priming without any further contribution by dendritic cells (DCs) and Ag. In this study, we report requirement for DCs, Ag, CD28 costimulation phase response. Depleting DCs or blocking after day 6 primary influenza A virus infection decreases virus-specific response inducing apoptosis, results decreased viral clearance. Furthermore, adoptively transferred fail expand DC, costimulation, cognate The absence also leads reduced survival as they undergo apoptosis mediated proapoptotic molecule Bim. Finally, IL-2 treatment restored costimulation. Thus, contrast naive cells, which an initial Ag-independent proliferation, expanding lungs require expansion. These requirements would greatly impair against viruses tumors that inhibit DC maturation chronic infections aging where CD28(-/-) accumulate.