A Neutralizing Prolactin Receptor Antibody Whose In Vivo Application Mimics the Phenotype of Female Prolactin Receptor-Deficient Mice

The study identified a human monoclonal antibody, 005-C04, that effectively blocked prolactin receptor (PRLR) signaling at nanomolar concentrations in vitro and mimicked the phenotype of PRLR-deficient mice in vivo. This antibody inhibited cell proliferation and signal transduction in specific cell lines and, when administered to female mice, caused reversible infertility and impaired lactation. Notably, it also stimulated hair regrowth in female mice. Compared to peptide-derived PRLR antagonists, the antibody demonstrated higher potency, noncompetitive inhibition, and a longer half-life, making it a valuable tool for long-term studies on PRLR signaling in various physiological and pathological contexts.