W. Peters

The chemotherapy of rodent malaria, XXII. The value of drug-resistant strains of P. berghei in screening for blood schizontocidal activity.

Data are provided on the activity of a variety of antimalarial drugs against drug-sensitive and drug-resistant lines of Plasmodium berghei in albino mice. Parallel data for the response of the drug-sensitive parasites to these compounds in vitro indicate whether the drugs have a chloroquine-like or quinine-like type of action, or neither. The value of this test system for drug evaluation is debated. It is concluded that the in vivo tests do provide a valuable indication of the potential use of a compound against drug-resistant malaria parasites of man. The tests may also provide a good indication of the future value of new compounds against strains of parasites that are already resistant to chloroquine. Where necessary, steps should be taken to protect promising new compounds.

The experimental chemotherapy of leishmaniasis. I. Techniques for the study of drug action in tissue culture.

Three lines of Leishmania have been grown successfully in tissue culture. L. mexicana mexicana, L.tropica major and L. donovani develop readily as amastigotes in dog sarcoma cells, and in a hamster peritoneal exudate cell line. The procedures used for cultivating both host cells and parasites are described, as are the methods employed for studying the senitivity of the parasites and hosts to drugs. It is concluded that the use of a tissue culture system is a valid way of determining the baseline sensitivity of a Leishmania to chemotherapy and the limitations of the technique are discussed. Illustrative data are presented of the response of two Leishmania species to amphotericin B and to a quinine analogue. L. mexicana mexicana is highly sensitive to amphotericin B and the response is shown to be consistent in duplicate experiments. L. mexicana mexicana and L. donovani are shown to have a different innate sensitivity to the quinine analogue.