Bivalent Nature of Incomplete Anti-D(Rho)

On “Incomplete” Anti-Rh Antibodies: Mechanism of Direct Agglutination Induced by Mercaptoethanol*

“…Our data, although not in accord with the original postulate of Pirofsky and Cordova (8,9), do suggest alternative explanations for the phenomenon they described.…”

“…Pirofsky and Cordova (8,9), on the basis of this ME-induced agglutination, postulated that incomplete anti-D is a bivalent antibody. They suggested that only one of the combining sites of the incomplete antibody is available for interaction with the red cell antigen and that alteration of the tertiary structure of the antibody molecule by ME exposes the previously hidden site, making it available for agglutination.…”

“…A more recent approach concerns the orientation of the combining sites of the incomplete antibody molecule. Pirofsky and Cordova (8,9) postulated that the incomplete anti-Rh antibody molecule has one reactive group available for lattice formation and one or more potentially reactive groups that are not available because of steric inaccessibility. Their experiments showed that in the presence of mercaptoethanol incomplete anti-Rh serum produced direct saline agglutination of the appropriate cells.…”

The Nature of Incomplete Erythrocyte Antibodies

“…The present report describes studies confirming the bivalent nature of incomplete erythrocyte antibodies. It was postu lated that incomplete erythrocyte antibodies have one available re active group and one or more reactive groups unavailable because of steric obstruction resulting from the molecular conformation of the incomplete antibody [5]. The postulate was tested by changing the tertiary structure of the incomplete antibody.…”

Transient Auto-Antibody Formation in a Case of Open Heart Surgery with no Signs of Increased Red-Cell Destruction

“…Auto-antibodies against soluble heart-muscle antigens appearing after cardiotomy in cases similar to the present one have been described [6], Acquired haemoly tic anaemia with a positive direct antiglobulin test has also been ob served [5]. At present it is not clear whether the rheumatoid affection of the heart indicates a predisposition to produce auto-antibodies.…”