Question on names of immunoglobins

[mdcabl at cc.newcastle.edu.au]

Hi all,
Just wondering, where did the names for the immunoglobins come from.  IgE
denotes erythema.  I think IgG is for gamma, but how were IgA, IgD and IgM
named? Please post your replies.  I'll bet I'm not the only immunologist that
don't know the history of immunoglobin names.  BTW I got the IgE ref from
Silverstien's History of Immunology.  He neglected to track the history of 
the naming conventions of all the immunoglobins. Also, how did we get the silly
nomenclature for pepsin digests of IgG.  F(ab')2 looks like a calculus problem.
I think F= fragment and ab=antigen binding but what's the prime symbol for?
Cheers!
Allen Black
Dept. of Pathology
Univ. of Newcastle