Conditions were elaborated to cultivate splenocytes of mice in medium-199 (Soviet production) changed a little by the addition of 200 mM of glutamine, 6 mM glucose, 60 unit/l of insulin, 5.10(-5) M 2-mercaptoethanol (final concentration), and of 5% serum of new-born calf. In such conditions of cultivation the value of the lymphocyte transformation coefficient lies within 3 and 10.