At the London School of Hygiene and Tropical Medicine, studies were commenced three years ago in the hope of developing the fluorescent antibody test as a means of differentiation of strains of Plasmodium falciparum. The work was carried out under the supervision of Professor Garnham, and financial support was received from WHO.
The first tests were carried out using the direct method of fluorescent antibody staining. The antigen was thin blood smears from animals with heavy malarial infections. These blood smears were fixed in acetone or with hydrochloric acid.
The techniques were established using sera from rats which, after recovering from an infection of P. berghei, had received repeated blood inoculations of the same parasite. The animals were immune, since no parasitemia occurred after challenge.
Similarly, P. vinckei antisera were produced by repeated inoculations of P. vinckei into hamsters. The latter sera were tested by the use of the indirect method with fluorescein-labeled anti-mouse serum as indicator.
Department of Parasitology, London School of Hygiene and Tropical Medicine, London, England.