Production of the lymphokine costimulator by activated mouse splenocytes under controlled conditions.

CBA/J mouse splenocytes were induced by concanavalin A to produce the lymphokine costimulator. No serum was needed for this process. Culture conditions were optimized in a 250 ml reactor vessel. While variations of the pH or agitation by stirring had no influence, high dissolved oxygen was found to increase the yields of costimulator even at the cost of cell viability.