PPIB,also named as CYPB,SCYLP,PPIase B and CYP-S1,belongs to the cyclophilin-type PPIase family and PPIase B subfamily. PPIases accelerate the folding of proteins. It catalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides. PPIB is secreted in biological fluids such as blood or milk and binds to a specific receptor present on the human lymphoblastic cell line Jurkat and on human peripheral blood lymphocytes.