Plasmodium falciparum gametocytogenesis in vitro.

Abstract

THE mechanism of sexual reproduction among malaria parasites is coming under increasing scrutiny. Gametogenesis is being unravelled by electron microscopy1 and by kinetic studies2. Gametocytogenesis on the other hand remains poorly understood in spite of earlier work3–5. The development of Plasmodium falciparum gametocytes is particularly intriguing because in man they develop in the deep tissue spaces, especially the spleen and bone marrow. The immature stages only rarely appear in the peripheral blood and as a result have escaped detailed experimental investigation until now. Furthermore, it has long been suspected that their development is prolonged5, taking 8–12 d, although there are suggestions to the contrary6,7. Immature gametocytes of P. falciparum have recently been reported in cultures thought to be composed only of asexual parasites8. I have used a similar microculture technique which has permitted the development in vitro of morphologically mature P. falciparum gametocytes and present here some preliminary observations on the process of gametocytogenesis in P. falciparum infections.