<unk> s, or Ig's, are a class of proteins in the blood, identified by their position after serum protein electrophoresis.  The most significant<unk> s are immunoglobulins.
Gamma globulin
Immunoglobulin G
Beta globulins
Immunoglobulin A
Albumin
Immunoglobulin D
Immunoglobulin M
Hemoglobin