The immunogenicity of malarial antigen obtained from infected human placenta.

: Malarial placenta antigen (MPA) was obtained from heavily parasitized human placenta. The immunogenicity of this antigen was tested by immunizing rabbits. The rabbit antiserum to malarial placenta antigen (anti-MPA) was absorbed with homogenate from nonparasitized human placenta. The anti-MPA serum was also absorbed with malarial placenta extract. Evaluation of the anti-MPA serum was done using the Ouchterlony immunodiffusion technique and by immunoelectrophoresis in agar. The results show that human malarial placenta antigen can stimulate the formation of anti-plasmodium antibodies. Although the antiserum produced also contained antibodies to some placental components, absorption studies showed that some malarial specific precipitinogens were produced. The significance of this in efforts to develop an effective malarial vaccine is discussed.