Problems in production of prostaglandin D2-specific antibody

Antisera raised in rabbits against prostaglandin D2 (PGD2) cross-reacted significantly with its dehydrates, 9-deoxy-delta 9-PGD2 (PGJ2) and 9-deoxy-delta 9,delta 12-13,14-dihydro-PGD2 (delta 12-PGJ2), but not with the other metabolites. To obtain PGD2-specific antibodies, we carried out the systematic study of the stability of PGD2 under various conditions. In an aqueous solution, 30%-40% of PGD2 was dehydrated to PGJ2 for 12 h at 37 degrees C, but only about 10%, for 96 h at 4 degrees C. Spectrophotometric studies showed that PGD2 was negligibly decomposed during the coupling to carrier protein. PGJ2 formed nonenzymatically was further converted to delta 12-PGJ2 by albumin, suggesting that cross-reaction would arise from the chemical and metabolic instability of PGD2 immunogen in recipient animals. A specific and high-affinity antiserum was obtained by immunizing a rabbit with the stable PGD2 analogue PGD2-11-methoxime. The antiserum thus obtained will eliminate the uncertainty that results from the use of antibodies with undesirable specificities.