IgM antibodies

[sundaram at rediffmail.com]

I have monoclonal antibodies IgM type which is in the  form of ascites. I also have ammonium sulphate ppt  of tissue culture supernatant of the same clone.
How do i preserve these ascites as IgM antibodies cannot be frozen at -20 because they will denature.Is it safe to store them at -70 with addition of 20 percent glycerol. what is the best method of purifying these Igm antibodies
kindly any one can clear my doubt.


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