T-cell-lymphokines and the production and function of accessory cells.

The recent purification and cloning of T cell-derived growth factors, should lead to rapid progress in delineating their role in the generation of accessory cells and the regulation of their function. The techniques that have allowed detailed in vitro studies of the T-dependent mast cells, should be generally applicable to other bone-marrow-derived cells. Although the T-dependent mast cell (i.e. P cells) of the mouse appear to have a special propensity to persist in vitro and special techniques that promote the emergence of immortalized clones will probably be necessary to grow useful quantities of other cell-types in vitro using PSF, it should prove possible to develop factor-dependent lines of various bone-marrow-derived accessory cells such as dendritic cells and Langerhans cells. The availability of clonal populations will permit analysis of the interaction of factors such as haematopoietic growth factors, interferon, glucocorticoids and other mediators involved in inflammatory reactions such as the prostaglandins and leukotrienes - not only in the regulation of Ia-antigen expression but also in modulation of other accessory cell functions such as the secretion of IL-1 and perhaps ultimately the processing and presentation of antigens.