A new paper in the "online ahead of issue" section of the journal Immunity captures interactions between CD4 T cells and dendritic cells (DCs) on film using intravital imaging. Although access to the full text of the article requires a subscription to the journal, the Quicktime videos can be viewed free of charge online. DCs are stained green, CD4 T cells are stained red. Some similar footage has been published previously, but this study goes a step further by using a system that allows the first encounter between DCs and antigen-specific CD4 T cells to be captured in real time.
Immunity
10.1016/j.immuni.2007.08.018
Susanna Celli,1,2 Fabrice Lemaître,1,2 and Philippe Bousso1,2,
1 Institut Pasteur, G5 Dynamiques des Réponses Immunes, Paris, F-75015, France
2 Inserm, Equipe Avenir, U668, Paris, F-75015, France
T cells interact with dendritic cells (DCs) for periods lasting from minutes to hours. However, a causal link between the duration of this interaction and the efficiency of T cell activation has not been established in vivo. Employing intravital two-photon imaging, we manipulated T cell-DC interactions in real time and found that the first T cell-DC encounter often resulted in a long-lived interaction. Moreover, the cessation of T cell receptor-major histocompatibility complex signals promoted cellular dissociation, suggesting that antigen availability on DCs regulates contact duration. Finally, at least 6 hr of in vivo T cell-DC interaction were required for naive CD4+ T cells to undergo clonal expansion. These results establish the importance of prolonged T cell-DC interactions for efficient CD4+ T cell activation in vivo.
Comments