Physically, each series of stylus will fit on alternate cartridge bodies.  However, these combinations are not supported by Ortofon, as they have not been tested.  Each cartridge series is designed with a synergistic combination in mind - that is, each stylus is made to compliment the magnet and coil configuration of each cartridge body.  For instance, using a DigiTrack stylus with a Scratch body will not provide the full benefit of either product, and might even provide undesired results, including (but not limited to) differences in output, unbalanced sound reproduction, etc.  

Note: In the case of the NightClub (mk1) and DJ series cartridges, it is perfectly alright to use the respective S (spherical) or E (elliptical) version stylus.  The cartridge bodies are designed to accommodate either of the respective series' stylus types.