Beginner's reference for glycobiology of Le(X) and Sialyl Le(X)

[kapweav at CENCOM.NET]

Hello,

I am trying to write a discussion for our paper on clusterin, a glycoprotein.
We have determined the structures of the carbohydrates and there are 
mostly NeuNAc-Gal-GlcNAc arrangements with some sialyl Lewis (X) groups.  
Could anyone offer me a good reference describing the biological 
functions of the above moieties?

Thanks in advance.

Jim.