This is from Sheldon Browns site
In practicality it should work:
Campagnolo/Shimano 8-speed cassettes have different spacing , so you can't generally get good indexing using a Campagnolo 8-speed wheel with a Shimano shift system or vice versa.
With 7-, 9- and 10-speed systems, the sprocket spacing between brands is close enough that it rarely causes any difficulty in practice.
For perfect matching, you might substitute different spacers or use a Jtek Shift Mate pulley adaptor.