Long-term myelopoietic cultures from the renal hematopoietic tissue of the rainbow trout, Oncorhynchus mykiss W.: phenotypic characterization of the stromal cells.

This study describes the conditions for the long-term culture of the renal hematopoietic tissue of the rainbow trout, Oncorhynchus mykiss, the characterization of the stromal cells, and their relationships with myelopoietic cells. The long-term cultures consisted of stromal cells, which supported active myelopoiesis. Stromal cells were analyzed by enzyme-cytochemical techniques and electron microscopy. Major stromal cell types in long-term cultures consisted of fibroblastic reticular cells and epithelioid cells. Myelopoietic cells differentiated in close association with the fibroblastic reticular cells, and mature granulocytes were released into the culture medium.