Evaluation of chemically modified carrier proteins for developing monoclonal antibodies against a clinically relevant mutation of cKIT.

In this report we show that combining double-chemically modified carrier proteins and hetero-functional cross-linkers allows preparing tailor-made hapten-protein carrier conjugates. Accordingly, a new carrier protein has been designed where carboxylic groups were transformed into highly reactive primary amino groups by reaction with ethylendiamine after activation with EDCI. The aminated protein carrier is then modified by different cross-linkers (hyper-activated proteins) at different conditions in order to control the conjugation ratio from 1 to >12 molecules of hapten per carrier protein. Finally, this novel strategy has been successfully used to develop antibodies against a short specific peptide corresponding to a point mutation (D816V) of cKIT, which is a clinically relevant mutation related to mastocytosis and gastrointestinal stroma tumor.