Assessment of mechanisms of action of immunosuppressive drugs using novel whole blood assays

WHOLE BLOOD ASSAYS are preferred because they better approximate the complex in vivo relationships among drug concentration, the binding of drug to plasma constituents and cellular targets, and the interaction among immune cells and their products. Additionally, the whole blood technique is more rapid and requires smaller sample volumes than methods that rely on purified lymphocytes. We assessed lymphocyte proliferation by measuring [H]-TdR incorporation and also assessed the expression of the T-lymphocyte surface antigens CD11a, CD25, CD54, and CD71 with flow cytometry analysis. We stimulated whole blood with concanavalin A (Con A) and phorbol 13-myristate 12-acetate (PMA) plus anti-CD28 (CD28) and determined the relative potencies of different immunosuppressive drugs on inhibition of lymphocyte function.