Anti-interleukin-2 receptor monoclonal antibodies in renal transplantation.

form an IL-2abc complex, which in turn binds IL-2 Although life-long administration of a multi-drug regiwith high affinity ( Kd=10−11 M ). The interaction of men of aspecific small-molecular immunosuppressants IL-2 with this receptor results in a rapid proliferation is most frequently used to prevent rejection of the of the antigen-activated T cells (clonal expansion) leadtransplanted organ, the administration of anti-T cell ing to effector T cells with helper, suppressor or cytoantibodies in the immediate post-transplant period toxic abilities. Depending on the epitope, some anti(induction therapy) as prophylaxis against rejection or IL-2Ra mAbs block the association of the a-chain with as anti-rejection therapy is still advocated to improve bc complex and the binding of IL-2 with its highlong-term allograft outcome. However, older polyaffinity receptor. Hence, the duration and magnitude clonal (ALS–ATG) and monoclonal (OKT3) antiof this antigen-specific immune response is suppressed T cell antibodies are associated with different sideby blocking only antigen-activated T cells, while cells effects: (i) the development of anti-xenogeneic antibod(resting T cells, B cells, monocytes-macrophages) not ies is associated with decreased immunosuppressive involved in the immediate rejection process are not or effects, serum sickness and anaphylactic reactions with minimally affected; moreover, no cytokine-release is repeated administration, (ii) cross-reactions with noninduced, possibly because the a-chain is unable to T cell tissue (e.g. thrombopenia, leukopenia), (iii) morcause signal transduction or internalization. In conbidity due to target cell activating antigen-specific trast, anti-IL-2Rb mAbs are less selective and effective reactions (cytokine release syndrome), and (iv) aspecbut they inhibit IL-2 binding as well as lymphocyte ific over-immunosuppression (e.g. CMV-infection, activation and proliferation [2]. post-transplant lymphoproliferative disorder (PTLD))