Analysis of rainbow trout peripheral blood leucocytes separated by flow cytometry cell sorting

The characterization of rainbow trout peripheral blood leucocytes (PBL) was carried out by flow cytometry (FCM) analysis and by transmission electron microscopy. Two major cell populations were identified in FCM analysis. One population showed small values in both forward scatter (FS) and side scatt er (SS), and the other population showed large values in both parameters. T hese major populations were divided into two sub-regions each (A/B and CID) . There was no significant difference in cell populations between sub-regio ns A and B. However, a difference was observed in the small and large lymph ocyte percentages between sub-regions C and D. The majority of regions (A a nd B) were constituted by neutrophils (56% and 66%, respectively), and mono cytes accounted for 9% and 7% of the cells, respectively. Large and small l ymphocytes were also present in these regions, accounting for 26% and 6% of the cells in sub-region A and 14% and 7% in sub-region B, respectively. In sub-regions C and D, cells were mainly constituted by large and small lymp hocytes (33% and 49% in C, and 7% acid 70% in D, respectively) and thromboc ytes (14% and 23%).