Isolation of antibodies against different protein conformations using immunoaffinity chromatography

A polyclonal antiserum obtained after the immunization of a rabbit with recombinant human sperm-specific glyceraldehyde-3-phosphate dehydrogenase lacking in 68 N-terminal amino acid residues (dN-GAPDS) was purified using different immunosorbents with immobilized dN-GAPDS in the native or denatured states. The procedure resulted in isolation of two types of polyclonal antibodies. The first type interacted with native recombinant dN-GAPDS as well as with native human sperm-specific glyceraldehyde-3-phosphate dehydrogenase, not cross-reacting with muscle glyceraldehyde-3-phosphate dehydrogenase (GAPD). The second type interacted with both native and denatured forms of the sperm-specific proteins, exhibiting some cross-reaction with GAPD. Thus, the suggested approach allows isolation of the antibodies against conformational or linear epitopes from the same polyclonal serum.