Optimized indirect 76br-bromination of antibodies using n-succinimidyl para-[76br] bromobenzoate for radioimmuno PET

Monoclonal antibody 38S1 was radiobrominated with the positron emitter 76Br (T1/2= 16.2 h). Indirect labeling was performed using N-succinimidyl para-(tri-methylstannyl)benzoate (SPMB) as the precursor molecule. SPMB was labeled using Chloramine-T yielding Nsuccinimidyl para-[76Br]bromobenzoate, which was then conjugated to the antibody. Optimization of the labeling conditions and further conjugation gave a total yield ( mean±max error) of 49±2%. The immunoreactivity of the antibodies was retained after labeling. Thus, antibodies intended for positron emission tomography can be labeled with 76Br, which gives high yields and preserved immunoreactivity when using the SPMB technique described.