Journal of Leukocyte Biology 37:585-595 (1985) Characterization of 3H-Uridine Incorporation and Messenger RNA Synthesis in Human Monocytes Activated to Secrete Alpha Interferon or Monocyte- Derived Fibroblast Growth Factor

Human monocytes are multifaceted cells with a wide range of immunoregula-tory functions and distinct secretory products. This manuscript reports on initial attempts to identify specific early macromolecular synthetic events associated with various types of human monocyte activation by observing the patterns of RNA synthesis displayed by human monocytes that are exposed to well char-acterized activating stimuli. It was found that muramyl dipeptide (MDP), an activator of monocyte-derived fibroblast growth factor (MD-FGF) release from monocytes, also stimulates a reproducible increase in human monocyte total 3H-uricline incorporation and cytoplasmic messenger RNA (mRNA) synthesis at 4 h following activation. In contrast, polyriboinosinic acid:polyribocytidilic acid (poly l:C), an excellent stimulator of monocyte alpha interferon (lFNa) release, did not cause a change in either 3H-uridine incorporation or cyto-plasmic mRNA production at any of the time points tested. Poly l:C was also found to be a poor stimulator of MD-FGF release. Conversely, MOP did not stimulate any detectable IFN release from human monocytes. The discrepancy between the patterns of macromolecular synthesis observed in human mono-cytes activated to secrete MD-FGF as compared with IFN indicates that diver-gent postactivation control mechanisms may be operative at the RNA level in the monocyte following activation of these two distinct functions. Key words: elutriator-purified human monocytes, macromolecular synthesis, mon-okine secretio