EFFECT OF IODINATION ON PRECIPITIN REACTION - ANTI-P-AZOPHENYLTRIMETHYLAMMONIUM (ANTI-AP) HAPTEN SYSTEM

Individual rabbit antisera against p-azophenylthrimethylammonium (Apz) hapten were iodinated at varying levels and tested for their ability to bind free homologous hapten and to precipitate homologous hapten diaotized to unreactive carrier protein. Of the 3 globulins tested, 2 were found to be insensitive to iodine up to 20 atoms/antibody molecule while the third was found to be partially iodine sensitive at much lower levels. Experiments with the insensitive globulins demonstrated that the aggregation of soluble immune complexes intop a macroscopic precipitate was not decreased by iodination. Loss of precipitating activity of the iodine sensitive globulin paralleled the loss of hapten binding activity. The hypothesis (that the effect of iodination upon precipitating antibodies in general is primarily upon binding) was successfully tested. The prediction (that an antibody insensitive to iodination with respect to hapten binding would also be insensitive to iodination with respect to hapten-carrier precipitation) was confirmed. © 1968.