Forcing TCR stimulation in the late phase of priming limits T cell divisions. GFP+ OT-I CD8+ T cells were adoptively transferred, and recipients were stimulated by an i.v. injection of OVAp. Intravital imaging of the popliteal lymph node was performed at 48 h. OVAp was reinjected during the imaging experiment. Mitosis events are shown (white square) before or immediately after OVAp reinjection. Recipients were also treated with anti-PD1 Ab as a means to further increase the number of T cell division. Note that OVAp reinjection inhibited T cell division.
