SRF-VP16 increases microglia and T cell activation in axonal injury. (A-H) Upon axotomy, microglia were activated at both time-points in the lesioned side expressing SRF-ΔMADS-VP16 compared to the control side (compare C, G with A, E). SRF-VP16 (B, F and D, H) enhanced microglia activation at both time-points. In addition, SRF-VP16 enhanced microglia association along the axons (arrows in H) and the nerve exit point (arrowheads in H) at 25 d.p.i. (see insert in H). (I-L) At 25 d.p.i., T cells entered the transected facial nucleus in control infected animals (K; the insert shows individual T cells), but not the intact facial nucleus (I). In animals expressing SRF-VP16, T cell infiltration was strongly enhanced in the lesion (L) but not the control side (J). T cells were also found along nerves (L). (M, N) Numbers of microglia/area are indicated for all conditions in the facial nucleus (M) and along the facial nerve (N). (O) Numbers of T cells/area are indicated for all conditions in the facial nucleus. Dashed lines depict outlines of the facial nuclei. Dashed boxes point at positions magnified by inserts. Scale-bar (A-L) = 100 μm; inserts (A-D, K, L) = 20 μm; inserts (E-H) = 100 μm.