Experiences with evaluation of immunosuppressive activity of alpha-globulin fraction of human blood plasma.

Presented are experiences with the determination of immunosuppressive activity of alpha globulin fraction of human blood plasma, crude (Cohn fraction IV), partially purified and so-called low-molecular isolates of these substances. For testing the following techniques were used: the lymphocytotoxic and lymphoagglutination test, rosette-inhibition tests with human lymphocytes and splenocytes of mice immunized with sheep erythrocytes, lymphocyte blastic transformation inhibition test using PHA stimulated cells as well as in the mixed culture, inhibition of haemolytic plaque formation tests, determination of GVH reactivity using regional tests in the popliteal nodes, determination of HVG reactivity by skin graft survival test, determination of the effect on formation of precipitins against soluble antigens. The best results were obtained with the determination of survival times for skin grafts and the regional test in the popliteal nodes Fairly reproducible results were obtained in experiments on influencing the humoral antibody response and inhibition of formation of precipitating antibodies. Of in vitro methods tests of inhibition of lymphocyte blastic transformation both after PHA stimulation and in the mixed culture are applicable. Fully unsuitable proved the rosette, lymphocytotoxic and lymphoagglutination tests. In vitro modification of haemolytic plaque formation tests. In vitro modification of haemolytic plaque formation test is unfit for testing the crude fractions or partially purified drugs, its in vivo modification seems more feasible provided a large panel of animals is examined.