Provided are Staphylococcal protein A (SpA) variants for binding
immunoglobulin (Ig), comprising a polypeptide which varies by one or more
amino acids from the amino acid sequence of a natural variable heavy
chain III ("VH3") Ig-Fab binding region ("binding region") of SpA,
wherein the polypeptide exhibits a different binding specificity for
Ig-Fab than does SpA or exhibits a different binding specificity for a
non-Ig target molecule than does SpA. Further provided are methods of
making the variants and methods of using the variants for in purification
of Ig as well as diagnostic and therapeutic intervention.