Antiidiotypic antibodies against anti-cGMP polyclonal antibodies

Affinity-purified polyclonal anti-cGMP antibodies were obtained from rabbit serum after immunization by succinyl derivative of cGMP coupled to bovine serum albumin. These antibodies were used to raise antiidiotypic antibodies in rats. Putative antiidiotypic serum inhibited the binding of [3H]cGMP to affinity-purified anti-cGMP antibodies. The influence of immunoglobulins isolated from antiidiotypic serum on the ion conductance of rod outer segment plasma membrane fragments from frog retina was studied in patch-clamp experiments. These immunoglobulins increased the conductance of ion channels acting like a natural agonist (cGMP). Preimmune immunoglobulins did not act. The data obtained suggest that antiidiotypic antibodies interact with regulatory cGMP-binding sites of the plasma membrane channels.