The plasmodium berghei-infection in isogenic F1(C57B1 x DBA)-mice. II. Antibodies and antigens in the serum.

Using the fluorescent antibody technique it was possible to demonstrate antibodies in the sera of F1(C57B1 x DBA)-mice already during the first week of infection with Plasmodium berghei, strain K 173. These antibodies reached high titers during the second and third week, but, nevertheless, the animals died from the infection. Coincidently with the FAT-antibodies plasmodial antigens could be found in the sera of infected mice. The numbers of these antigens increased in the course of the infection. Finally up to seven could be precipitated by using a double diffusion technique in cellulose acetate membranes. Since antibodies directed against these antigens were only found in immune animals they must be different from the antibodies measured in the FAT. Comparison of the antigens found in the sera of infected animals with antigens prepared by physical desintegration of parasite material showed that in the sera antigens appeared which could not be demonstrated in the plasmodial extracts. If parasite material was phagocytized by macrophages in cell cultures in the culture supernatant also antigens appeared which could not be found in the plasmodial extracts. Similar antigens were found if isolated parasites were allowed to degrade without the action of phagocytic cells.