Monocyte activating factor originally found in sarcoidosis sera. I. Production of a similar factor by monocytes pretreated with interleukin 1

The culture medium for normal human monocytes pretreated with interleukin (IL)-1, either α and β, induced normal human monocytes to spread and to increase Fc (IgG) receptor sites, angiotensin converting enzyme production and glucose consumption of normal human monocytes, suggesting that this medium contains a monocyte activating factor(s). On TSK G3000SW gel filtration, the major monocyte activating factor in the culture medium and that in sarcoidosis serum were eluted at the same position (with a molecular weight of about 70,000). Thus, IL-1 may be able to induce normal human monocytes to produce a monocyte activating factor quite similar to that found in sarcoidosis serum.