A monoclonal antibody specific for the phosphorylated epitope of rhodopsin: comparison with other anti-phosphoprotein antibodies.

Monoclonal antibody A11-82P has been prepared and shown to recognize the phosphorylated epitope of bovine rhodopsin. Antibody A11-82P is quite specific for phosphorylated rhodopsin; only the 200K neurofilament protein has been found to cross react, and this requires 10(3) more protein for the same extent of binding as evaluated by competition ELISA. An immunocytochemical study of light-adapted retina showed strong staining of rod outer segments. Survey of a variety of rat tissues showed no specific staining with A11-82P, further demonstrating that this antibody is quite specific for phosphorylated rhodopsin. Two other antibodies were found to bind both phosphorylated rhodopsin and the 200K neurofilament protein: RT-97 (1) and MAP 1B3 (2). Both antibodies also recognized other phosphoproteins and appear to be less specific in their structural requirements for a phosphoprotein epitope than is A11-82P.