Bindung radioaktiv markierter monoklonaler Antikörper an Interleukin-2 und -6 Rezeptoren und deren Bedeutung für die Diagnostik der Transplantatrejektion

Abstract

Visualizing transplant rejection using radiolabeled monoclonal antibodies (mAb) is an appealing concept, but limited by the lack of specificity of the mAbs investigated [1]. Since considerable progress has been made to identify transplant rejection as a complex immune activation, radiolabeled mAbs against subsets of activated graft in- filtrating cells might have advantages in transplant rejection imaging. The IL-2R is known to play an important role in transplant rejection, whereas the significance of the IL-6R is less well defined. Anti-IL-2R mAbs have been proven to prevent and reverse acute allograft rejection [2], whereas increased IL-6 blood levels have been found in acute rejection episodes of lung and heart-lung recipients [3]. It remained unclear whether time course and binding efficiency of radiolabeled anti-IL-2R and anti-IL-6R mAbs are suitable for rejection imaging. Therefore, we probed the in vivo presence for IL-2 and IL-6 receptors at various time points during the rejection process with the mAb ART18, a mouse IgG directed against the p55 subunit of rat IL-2R, and the mAb 15A7, a rat IgG2b directed against the mouse IL-6R [4].