Immune cell entry to the CNS--a focus for immunoregulation of EAE.

T-cell-derived cytokines are therefore individually unnecessary and collectively insufficient for microglial response. This somewhat provocative interpretation does not exclude a role for T-cell cytokines in induction of a microglial response in EAE, but it may be easier to show a non-requirement then to prove such a role. The point that emerges is that cytokine production in the CNS parenchyma is itself dependent on the prior infiltration of immune cells, and that without immune cell entry, EAE does not occur. This identifies events at the BBB, and in particular in the perivascular space, as critical immunoregulatory events in development and progression of EAE.