IN-VITRO HEMATOPOIESIS INDUCED IN A RAINBOW-TROUT PRONEPHRIC STROMAL CELL-LINE (TPS)

To rapidly and efficiently establish haemopoietic cultures from rainbo w trout, O. mykiss, a method to elicit haemopoiesis on a trout proneph ric stromal cell line (TPS) was developed. The system used cocultures of pronephric cell suspensions with subconfluent cultures of TPS cells . The initiation of haemopoiesis in these cocultures occurred rapidly, and the duration of sustained haemopoiesis, after a single inoculum o f fresh exogenous pronephric cells, exceeded 1 year. Analysis of cells removed from the supernatants of these cocultures revealed production of granulocytes, lymphocytes and erythrocytes. Ultrastructural analys is of haemopoietic cocultures revealed close associations between the developing blood cells and the microenvironment created by the stromal cells. The capacity of the TPS cell line to support haemopoiesis was superior to that of the RTG-2, suggesting that TPS has retained specif ic characteristics of the pronephric stroma. The availability of this culture system should facilitate studies on in vitro haemopoiesis in f ish. (C) 1998 Academic Press Limited.