In all previous studies, bloodstream forms of Trypanosoma brucei could be grown in vitro only when supported by a feeder layer of mammalian fibroblasts. We have axenically cultivated bloodstream T. brucei by adding L-cysteine at regular intervals and appropriate concentrations. The optimum cysteine concentration depends on cell density and is close to physiological serum levels. At concentrations greater than 24 mg/liter (2 X 10(-4) M), cysteine was acutely toxic to trypanosome concentrations of 3 X 10(7)/ml. Toxicity was prevented by addition of pyruvate or catalase, which neutralize H2O2 produced by cysteine autoxidation. In uptake studies using [35S]cysteine and [35S]cystine, T. brucei efficiently incorporated only cysteine. The Km for cysteine uptake was 4 X 10(-4) M. Cystine supported axenic growth if low concentrations of 2-mercaptoethanol were added at regular intervals.
Cysteine eliminates the feeder cell requirement for cultivation of Trypanosoma brucei bloodstream forms in vitro.
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M Duszenko, M A Ferguson, G S Lamont, M R Rifkin, G A Cross; Cysteine eliminates the feeder cell requirement for cultivation of Trypanosoma brucei bloodstream forms in vitro.. J Exp Med 1 October 1985; 162 (4): 1256–1263. doi: https://doi.org/10.1084/jem.162.4.1256
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