Immunoquantitation of antibody to placental phosphatase by single radial immunodiffusion; effect of antibody avidity and immunization protocol.

The radial immunodiffusion method was used to titer antisera to human placental alkaline phosphatase. When this was done with diluted enzyme and antisera, it was found that early-course antisera consistently yielded low titers. This observation was consistent with the known low avidity of such antisera.