T cell arrest in the lymph node is dependent on T cell activation status. GFP+ OT-I CD8+ T cells were adoptively transferred, and recipients were stimulated by an i.v. injection of OVAp. At 30 h, a second cohort of SNARF-labeled OT-I CD8+ T cells was adoptively transferred. Intravital imaging of the popliteal lymph node was performed 18 h later. Note that T cells from the second (red) but not the first (green) cohort are arrested (circles).
