(A-B) Details of the periphery of tissue cysts from chronically infected mice identifying the host cells (HC) as neurons due to the formation of synapses (arrows). Based on the structure of the synapse the cysts appear to be within a neuronal dendrite. V – neurosecretory vescicles; CW – cyst wall; Br – bradyzoite. Bars represent 100 nm. (C) Low power of a cyst containing numerous bradyzoites (Br) within a host cell (HC). Note the absence of inflammatory cells. Bar is 1 μm. (D) Low power of a ruptured tissue cyst showing numerous inflammatory cells (M) around and invading through breaks in the cyst wall into the tissue cyst. Bar is 10 μm. Inset: Similar area to that in D immunostained with an antibody to the cyst wall (CC2) showing the disruption to the tissue cyst wall (arrows) and the surrounding inflammatory cells. Bar is 10 μm. (E) Detail from D showing bradyzoites (Br) that had been phagocytised by inflammatory cells. Bar is 1 μm.