Studies on serum requirements for the cultivation of Plasmodium falciparum. 1. Animal sera

Pooling a number of freshly collected lots of human serum eliminated the variability observed between individual serum samples, and reduced the amount of human serum required for optimum parasite growth in continuous culture. In the present experiments the addition of 50 ml of pooled human serum per litre of RPMI (5% serum) resulted in optimum growth. Batches of RPMI 1640 supplemented with freshly collected and pooled lots of bovine, porcine, goat, equine, or ovine sera, as well as commercially available fetal-and young-calf sera, were tested and compared with 5% pooled human serum. Various combinations of animal sera with and without Neopeptone were also examined as supplements to the basic culture medium. As an alternative to human serum, only bovine serum supplemented with Neopeptone could support continuous parasite growth, but at significantly reduced levels. Continuous parasite growth was obtained by transferring parasites directly from 5% human serum into medium plus freshly collected, Neopeptone-supplemented, pooled bovine serum, without any need for an adaptation period.