[Protein-analysis] protein purification for immunization?

[Sonja Kowalczuk]

I have created GST-fusion proteins and purified them on glutathione 
sepharose 4B columns, so the protein was eluted with 10mM glutathione in 
50mM Tris-HCl pH7.5.
I want to use the fusion proteins to immunize some rabbits.
Do I need to get rid of the Tris to have the protein in water only (and if 
so how do I do this)?
Thank you
-Sonja.