Figure 3
Viral pre-challenge increases the expression of ICAM-1 in the brain. Baseline ICAM-1 expression (A) did not differ significantly from ICAM-1 expression after the microinjection of vehicle, in the presence of intravenous AdLuc (B). Intrastriatal IL-1Β induced a generalised up-regulation of ICAM-1 expression, which was most evident around vessels actively involved in recruitment of leukocytes (C, arrowhead). In the brains of animals microinjected with IL-1Β, in the presence of intravenous AdLuc (5 × 109 CFU), this up-regulation was more notable still (D). Note the two distinct subtypes of vessels; smaller vessels not actively involved in recruitment (arrowhead) and larger vessels showing increased ICAM-1 positivity, which were the ones where cuffs of neutrophils could be seen (inset). Counterstain is cresyl violet. Scale bars represent 50 μm. CFU, colony-forming unit.