Abstract: The present disclosure provides novel immunoglobulin proteins that bind to a human natriuretic peptide receptor 1 (NPR1) agonist, preferably an anti-NPR1 antibody. In certain embodiments, the proteins of the disclosure comprise at least one immunoglobulin variable domain that binds to an anti-NPR1 antibody. In certain embodiments, the proteins of the disclosure are useful in blocking and/or reversing the effect of an administered anti-NPR1 antibody. In certain embodiments, the antigen-binding proteins are useful for effective management of blood pressure and hemodynamics in humans.