Identification of patient-specific peptides for detection of M-proteins and myeloma cells

We have taken advantage of the selection power of phage display technology to define specific peptide mimotopes that recognize individual M-proteins, isolated from patients with multiple myeloma. Preferred amino acid motifs o f phages binding to M-proteins were identified in 6/9 patients investigated . Chemically synthesized peptides, corresponding to the phage-displayed pep tide inserts, were used to verify the specificity of binding in competition assays. The peptides were able to bind to the M-proteins, as well as the m yeloma cells, with high sensitivity and specificity, Employing simple immun ological techniques, <0.01 g/l of M-protein could be quantified, suggesting a never way for monitoring minimal residual disease in the production of g uidelines for adjusting or reintroducing conventional chemotherapy. The pep tide mimotopes defined by this technology may be useful as tumour-specific targeting agents and as a tool for purging cells in autologous bone marrow transplantation.