Characterization of monoclonal antibodies against prostaglandin E2: Fine specificity and neutralization of biological effects

The specificity and heterogeneity of the immune response of BALB/c mice immunized with prostaglandin E₂ (PGE₂) coupled to thyroglobulin was studied. All the animals (n = 50) responded to PGB₂, a transformation product of PGE₂. However, following repeated injections most of the animals (n = 30) were also able to respond to PGE₂. Cellular hybridizations were performed and five anti-PGE₂ monoclonal antibodies were isolated and analysed. They are mainly directed against the ring and the ω-chain of PGE₂ but their specificity toward the α-chain is more limited. The association constants are greater than to 1 × 10⁹M^?1. The monoclonal antibody 8E.57.71 (K_a = 1.3 × 10¹⁰M^?1) is particularly convenient for sensitive radioimmunoassays (detection limit 25pg/ml, when iodinated tracer is used). Anti-PGE₂ monoclonal antibodies were found to neutralize the specific binding of ³H]PGE₂ to rat brain hypothalamic receptors and to inhibit the PGE₂ induction of rat fundus muscular contraction.