FIELD: medicine. SUBSTANCE: method involves determining effectiveness of serum factor action upon antibody synthesis process in inducing primary immune response using in vitro culture. Mice are intravenously immunized with sheep erythrocytes at a dose of 20 x 106 cells per 1 mouse. Mouse splenocyte homogenate is produced in 96 h and cultivated with blood serum of a testee. Antibody-creating cell number is counted in the culture of xenogenous lymphocytes of the testee relative to the like value in the control sample in 0, 24, 72 and 96 h from the beginning of culturing. Difference value between the case and control samples being positive, testee blood serum factor action is evaluated as stimulating one. The difference value being less than zero, it is evaluated as inhibiting one. EFFECT: enhanced accuracy in describing antibodygenesis control mechanisms state; minimum material consumption. 1 tbl
