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

Abstract

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 of phages binding to M-proteins were identified in 6/9 patients investigated. Chemically synthesized peptides, corresponding to the phage-displayed peptide 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 myeloma cells, with high sensitivity and specificity. Employing simple immunological techniques, < 0.01 g/l of M-protein could be quantified, suggesting a novel way for monitoring minimal residual disease in the production of guidelines for adjusting or reintroducing conventional chemotherapy. The peptide 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.