Buffalo colostrum- A novel substitute of human serum for the cultivation of Plasmodium falciparum in vitro

Abstract

In vitro cultivation of erythrocytic stages of Plasmodium falciparum requires supplementing the culture medium with human serum. The present study was carried out to explore an alternative to human serum. Different human serum samples were found to vary considerably in their ability to support the growth of erythrocytic stages of P. falciparum in vitro. These results strongly suggested the use of pooled human serum for comparing the growth of parasites in medium augmented with other supplements. Parasites could multiply for a few cycles only in RPMI (Roswell Park Memorial Institute) medium supplemented with serum obtained from pig, goat, sheep or buffalo. Continued cultivation could not be achieved using any one of these animal sera. Ability of bovine colostrum was investigated as an alternative to human serum. Buffalo colostrum, 10%(v/v) 'suitably prepared' supported the continuous growth and multiplication of P. falciparum . Morphologically both asexual and sexual stages appeared normal and healthy, but the multiplication rate of parasites grown in colostrum augmented medium was found to be lower than that in serum-supplemented medium. The one month of uninterrupted cultivation of P. falciparum registered 106 fold increase in parasite density compared to 1010 fold multiplication recorded in control culture with 10% serum supplement. Cow colostrum failed to support the growth and multiplication of parasites beyond 6 days in culture. The initial positive results with buffalo colostrum hold promise and should be explored further as a potential substitute for human serum for continuous in vitro propagation of erythrocytic stages of the malignant malaria parasite.