High affinity binding of reovirus type 3 to cells that lack beta adrenergic receptor activity

A previous report demonstrated both immunological crossreactivity and structural similarity between the mammalian beta adrenergic receptor and the cell surface receptor for the reovirus type 3 (14). We now demonstrate that reovirus type 3 can bind selectively and with high affinity to cells that lack beta adrenergic receptor activity (L-cells). The present study was also designed to determine what effect reovirus binding has on beta adrenergic receptor function in cells (DDT₁) that possess an intact ligand binding site. Based on computer analysis of reovirus competitive inhibition curves, the apparent dissociation binding constants (Kd) for reovirus binding to DDT₁ and L-cells are 0.1 nM and 0.25 nM, respectively. High affinity [¹²⁵I]-iodocyanopindolol (CYP) binding to beta adrenergic receptors can also be demonstrated in DDT₁ cells but not in L-cells. In agreement with these ligand binding studies, adenylate cyclase activity is stimulated by the beta receptor agonist isoproterenol in DDT₁ cell membranes but not in L-cell membranes. In addition, isoproterenol increases cAMP levels in DDT₁ cells but not in L-cells. Neither reovirus serotype stimulates cAMP levels in either cell line, nor do they influence beta-adrenergic agonist stimulation of cAMP in DDT₁ cells. These results argue against identity of the receptors for reovirus type 3 and beta adrenergic ligands.