Abstract
We investigated the effect of the ingredients in serum-free cultures, in which serum was completely replaced by albumin, cholesterol and transferrin, on the growth of murine granulocyte/macrophage progenitor cells (colony forming unit in culture: CFU-C) stimulated by serum-free PWM-SCM and the influences of purified granulocyte-macrophage colony stimulating factor (GM-CSF) in serum-free cultures. The results were as follows: 1) The number of CFU-C colonies reached a peak after 4 days of incubation. 2) A linear relationship was observed between the number of CFU-C colonies and the number of inoculated bone marrow cells. 3) Serum-free cultures could support CFU-C colony growth to the same degree as that in serum-containing cultures. Also, no significant differences were found in the types of colonies grown in both cultures. 4) Bovine serum albumin (BSA) and cholesterol were considered to play the most important roles among the ingredients in serum-free cultures. 5) Purified GM-CSF supported CFU-C colony growth in serum-free cultures and mole than a half of the colonies formed were GM-colonies. These results showed the usefulness of our serum-free cultures for studying the granulopoiesis in vitro without the infiuences of various substances in the serum.
