SYNTHETIC PEPTIDE LIGANDS OF THE ANTIGEN-BINDING RECEPTOR INDUCE PROGRAMMED CELL-DEATH IN A HUMAN B-CELL LYMPHOMA

Peptide ligands for the antigen binding site of the surface inmunoglob ulin receptor of a human B-cell lymphoma cell line were identified wit h the use of filamentous phage libraries displaying random 8- and 12-a mino acid peptides. Corresponding synthetic peptides bound specificall y to the antigen binding site of this immunoglobulin receptor and bloc ked the binding of an anti-idiotype antibody. The ligands, when conjug ated to form dimers or tetramers, induced cell death by apoptosis in v itro with an IC50 between 40 and 200 nM. This effect was associated wi th specific stimulation of intracellular protein tyrosine phosphorylat ion.