Abstract
Spontaneously released merozoites were harvested from cultures in which 42-90% of the erythrocytes had been infected with mature forms of Plasmodium falciparum at the start of incubation. The mature forms had been extracted from asynchronous cultures by the use of Ficoll and Plasmagel gradients. As the mature forms consisted of both trophozoites and schizonts, merozoites were released into the culture medium over a long period of time. The synchrony of merozoite release did not appear to be improved by prior exposure of parasites to sorbitol. Over this prolonged period of incubation, the yield of merozoites was disappointingly low in cultures containing 2.5% of erythrocytes. At erythrocyte concentrations of 0.01-0.25%, 3-10 times more merozoites were released into the medium; 0.4-2.3 merozoites per initial mature form were harvested over a 15-19-hour period. In addition to merozoites, contents of the culture medium included intact erythrocytes, ghost cells, and other cellular fragments. Only intact erythrocytes were effectively removed from the medium by simple or Ficoll gradient centrifugation. Merozoite preparations that are free from host cellular material are important in the development of a human malaria vaccine.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Haynes J. D., Diggs C. L., Hines F. A., Desjardins R. E. Culture of human malaria parasites Plasmodium falciparum. Nature. 1976 Oct 28;263(5580):767–769. doi: 10.1038/263767a0. [DOI] [PubMed] [Google Scholar]
- Mitchell G. H., Richards W. H., Butcher G. A., Cohen S. Merozoite vaccination of douroucouli monkeys against falciparum malaria. Lancet. 1977 Jun 25;1(8026):1335–1338. doi: 10.1016/s0140-6736(77)92551-x. [DOI] [PubMed] [Google Scholar]
- Mrema J. E., Campbell G. H., Miranda R., Jaramillo A. L., Rieckmann K. H. Concentration and separation of erythrocytes infected with Plasmodium falciparum by gradient centrifugation. Bull World Health Organ. 1979;57(1):133–138. [PMC free article] [PubMed] [Google Scholar]
- Rieckmann K. H., Campbell G. H., Sax L. J., Mrema J. E. Drug sensitivity of plasmodium falciparum. An in-vitro microtechnique. Lancet. 1978 Jan 7;1(8054):22–23. doi: 10.1016/s0140-6736(78)90365-3. [DOI] [PubMed] [Google Scholar]
- Siddiqui W. A. An effective immunization of experimental monkeys against a human malaria parasite, Plasmodium falciparum. Science. 1977 Jul 22;197(4301):388–389. doi: 10.1126/science.406671. [DOI] [PubMed] [Google Scholar]
- Trager W., Jensen J. B. Human malaria parasites in continuous culture. Science. 1976 Aug 20;193(4254):673–675. doi: 10.1126/science.781840. [DOI] [PubMed] [Google Scholar]