Polyantibody against β2-adrenergic receptor extracellular domain act as an agonist to this receptor in porcine model

In the present study, we designed a peptide of the second outer loop of porcine β2-AR, and expressed the fusion protein in E. coli. Polyantibody was prepared in New Zealand White rabbit. The biological activity of the antibodies was measured both in vitro and in vivo. The antibody titer was 1:4,096,000. Western blots revealed that the prepared antibodies specifically reacted with correspondent antigens. Intracellular cAMP level of porcine skeletal muscle cells was significantly elevated after treatment of clenbuterol and anti-β2-AR/K31A relative to negative serum (P<0.01). ICI118551, blocker of β2-AR, decreased the elevation of intracellular cAMP (P<0.01). MAP kinase was phosphorylated after being treated with clenbuterol and anti-β2-AR/K31A. The backfat thickness decreased by 13% after immunization with the fusion protein. These results indicate that the polyantibody exerted a similar activity to its ligand in porcine model, and may be developed as a new agonist to β2-AR.