Chickens were immunized with two synthetic peptide / keyhole limpet hemocyanin (KLH) conjugates. These synthetic peptides corresponded to different regions of the Tyrosine Hydroxylase gene product, but were shared between the human (P07101, NCBI) and mouse (P24529, NCBI) sequences. After repeated injections into the hens, immune eggs were collected, and the IgY fractions were purified from the yolks. These IgY fractions were affinity-purified using a peptide column, and the concentrations of the eluates adjusted to 200 ug/ml. Finally, equal volumes of both affinity-purified anti-peptide antibody preparations were mixed, and the preparation was filter-sterilized.