Fig. 1.

Ab1 (8019) binding inhibition to Ab2 (3H1) by immune sera. Plates were coated with 3H1 and the binding of ¹²⁵I-labeled 8019 was tested for inhibition in the presence of immune sera at 1:20 dilution. a, b Sera were collected 8–10 days after each immunization and used for analysis. Preimmune sera at 1:20 dilution showed less than 10% binding inhibition. c Sera were collected from groups of mice after final immunization and were diluted with PBS before analysis. Results in a–c are representative of three independent experiments