We firstly identified three cyclophilins (Ca-CyPs), including Ca-CyPA, Ca-CyPB and Ca-PPIL3 from the oyster, C. ariakensis.

All the Ca-CyPs contain a typical CyP-PPIase domain with its signature sequences and Ca-CyPB contains an N-signal peptide.

Tissue distribution studies revealed that Ca-CyPs were expressed in all examined tissues with the highest levels in hemocytes.

RLO incubation increased the expression levels of Ca-CyPs, indicating Ca-CyPs might be involved in oyster immune response.