Background of the antigen
Peptidyl-prolyl cis-trans isomerase (PPIL1) is a member of the cyclophilin family of peptidylprolyl isomerases (PPIases). The cyclophilins are a highly conserved, ubiquitous family, members of which play an important role in protein folding, immunosuppression by cyclosporin A, and infection of HIV1 virions. Based on similarity to other PPIases, this protein could accelerate the folding of proteins and might catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides.