Production a monoclonal antibody specific to granulocytes of swimming crab (Portunus trituberculatus) and its cross reactivity with other crustaceans

In this study, a monoclonal antibody (mAb) 3F4 specific to granulocytes of swimming crab, Portunus trituberculatus, was obtained by immunizing mice with whole haemocytes. mAb 3F4 showed strong immunofluorescent reaction with granulocytes, but no reaction with hyalinocytes. The positive cell percentage of granulocytes was 86.3% detected by Flow cytometry (FCM). A special antigen with molecular weight of about 26 kDa was further recognized by mAb 3F4 in haemocytes of P. trituberculatus. mAb 3F4 also showed strong cross-reactivity with haemocytes of Eriocheir sinensis and Petalomera japonica, but no reaction with other crustaceans tested. In E. sinensis, the positive cell percentage was 73.4% for granulocytes and 59.8% for hyalinocytes; while in P. japonica, the positive cell percentage was 81.2% for granulocytes and 7.1% for hyalinocytes. There was also a special antigen with molecular weight of about 31 kDa identified by mAb 3F4 in haemocytes of E.sinensis, but no corresponding protein band in P. japonica haemocytes. These results demonstrated that mAb 3F4 can be used as a marker for granulocytes of crabs.