cAMP production Induced by Relaxin‑3 and Neutralization by Human Relaxin‑3 Antibody. Recombinant Human Relaxin-3 (Catalog # 3107-RN ) induces cAMP production in the THP-1 human acute monocytic leukemia cell line in a dose-dependent manner (orange line), as measured by cAMP Parameter Assay Kit (Catalog # KGE002B ). cAMP production elicited by Recombinant Human Relaxin-3 (25 ng/mL) is neutralized (green line) by increasing concentrations of Mouse Anti-Human Relaxin-3 Monoclonal Antibody (Catalog # MAB31071). The ND 50 is typically 1-5 µg/mL.