PAF-induced eosinophilic and basophilic differentiation in human hematopoietic precursor cells.

PAF enhances the maturation and differentiation of basophils and eosinophils from hematopoietic precursor cells. These enhancing effects of PAF were inhibited by PAF antagonists, such as WEB-2086. Also, the coexistence of antibodies to IL-1 and IL-3 markedly inhibited the PAF-induced differentiation. Human recombinant IL-1 alpha/beta induced differentiation of hematopoietic precursor cells into both cell lines, and this was completely inhibited by the coexistence of antibody to IL-3. Interleukin 1 beta and IL-3 were detected in the cultured supernatant of PAF-stimulated mononuclear leukocytes obtained from human umbilical blood. From these findings, it is suggested that PAF triggers the production of these growth factors via specific receptors, and the growth factors produced may directly cause the differentiation and maturation of the precursor cells.