Stabilization of protein without glycerol - protein has to be ip injected in mice (Apr/21/2006 )

Dear all,
I am presently purifying a protein, which has to be used in mice, by i.p. injection.
Thus, after purification I have to change buffer, into PBS, for injection. However, it appears that the protein precipitates when I change the buffer from Tris, NaCl, urea, to the PBS buffer, either by dialysis or PD-10 column - the latter of which I prefer to use.
Normally, I would try to use 10-20% glycerol, which normally very well prevents precipitation. However, as glycerol according to some studies is antigenic or pro-inflammatory, this cannot be used.
I was thinking to use sucrose instead, as this should be okay.
Does anybody have experience in this direction?
Thanks,
Ras

if this is for antibody then there is no problem using denatured protein. run your protein on sds page, cut out and elute the band. denatured protein should have no problem being soluble in PBS.