Affinity of Protein A/G for IgG Types from Different Species

Protein A and G are popular choices for antibody purification, because they are both stable and target selective. IgG class antibodies from multiple species bind to protein A and/or G, allowing antibody to be captured on protein-bound beads. Protein A and G bind IgG subtypes with varying affinities, determined by species and the properties of the heavy chain. Below is a chart that reports the affinity of protein A and G for various species immunoglobulin subtypes.
 

Species Immunoglobulin Binding to Protein A Binding to Protein G
Human lgG (normal) ++++ ++++
lgG1 ++++ ++++
lgG2 ++++ ++++
lgG3 - ++++
lgG4 ++++ ++++
lgM - -
lgA - -
lgE - -
Mouse lgG1 + ++++
lgG2a ++++ ++++
lgG2b +++ +++
lgG3 ++ +++
Rat lgG1 - +
lgG2a - ++++
lgG2b - ++
lgG2c + ++
Goat lgG +/- ++
Rabbit lgG ++++ +++
Sheep lgG +/- ++