ABSTRACT
Ligation of CD28 and CD86 leads to signals that are required for the production of interleukin-2, a process that is implicated in the regulation of T-cell anergy and programmed cell death [27-30]. An HTRF assay was constructed to screen for smallmolecule antagonists of this interaction, which could be considered possible drug targets. The acceptor, XL665, was covalently bound to antihuman antibody that recognizes the Fc region. CD28 was expressed as a fusion protein to the human immunoglobulin (Ig) domain. The other binding partner, CD86, was expressed as a fusion protein with a rat Ig domain, recognized by biotinylated sheep anti-rat antibody. Streptavidin-EuK binds to complete the HTRF reaction [31] (Fig. 16).
