Several poxvirus immune evasion proteins make use of a conserved β-sandwich-domain that we propose calling a "PIE scaffold". PIE domain-containing proteins are abundant among chordopox. We estimate there may be as many as 20 separate PIE families. My current aim is to determine the function of as many PIEs as possible, to understand their role in immune evasion, and by x-ray crystallography understand how they bind so many disparate ligands.