Development of a Novel, Anti-idiotypic Monoclonal Anti-prolactin Antibody That Mimics the Physiological Functions of Prolactin

In this work, we prepared a panel of monoclonal anti-idiotypic antibodies to ovine prolactin (oPRL) by the hybridoma technique. Among these antibodies, one anti-idotypic antibody (designated B7) was chosen for further characterization by a series of experiments. We first demonstrated that B7 behaved as a typical $Ab2{\beta}$ based on a series of enzyme-linked immunosorbent assays. Subsequently, the results of a competitive receptor-binding assay confirmed that B7 could specifically bind to the prolactin receptor (PRLR) expressed on target cells. Finally, we examined its biological activities in CHO-PRLR and Nb2 cells and observed that B7 could activate Janus kinase 2-signal transducer and activator of transcription signalling in CHO-PRLR and Nb2 cells and induce BaF3 proliferation. The present study suggests that i) B7 can serve as a PRLR agonist or PRL mimic and has potential applications in regulating mammary gland development, milk production and maintenance of lactation in domestic animals and ii) B7 may be a biological reagent that can be used to explore the mechanism of PRLR-mediated intracellular signalling.