Laboratory of Tropical Medicine and Hygiene, Medical Department, Tulane University, New Orleans, Louisiana.
J Exp Med. 1912 Oct 1;16(4):567-79. doi: 10.1084/jem.16.4.567.
The asexual cycle of Plasmodium vivax and Plasmodium falciparum has been cultivated in vitro in human blood. The parasites have been grown also in red blood cells in the presence of Locke's solution, free of calcium chlorid and in the presence of ascitic fluid. The parasites grow within red blood cells and there is no evidence that they can be grown outside of these cells. The parasites are destroyed in a very few minutes in vitro by normal human serum or by all modifications of serum that we have tested. This fact, together with numerous observations of parasites in all stages of growth apparently within red cells, renders untenable the idea of extracorpuscular development. Leucocytes phagocytize and destroy malarial plasmodia growing in vitro only when the parasites escape from their red blood cell capsule or when the latter is perforated or becomes permeable. Successive generations of Plasmodium vivax and Plasmodium falciparum have been cultivated in vitro by removing the leucocytes from the culture and by transplanting to fresh red blood cells and serum at proper intervals. The asexual cycle of Plasmodium vivax and Plasmodium falciparum cultivated in vitro does not differ from the same cycle growing in vivo. The sexual cycle has not been cultivated, though we have obtained some evidence of the possibility of its accomplishment. There can no longer be any doubt that Plasmodium vivax and Plasmodium falciparum are separate and distinct species. When grown in an identical culture medium and under exactly the same conditions they remain distinct. In twenty-nine cultures of aestivo-autumnal parasites many forms and sizes have been observed, so that evidence is supplied of the occurrence of different varieties of aetivo-autumnal malarial plasmodia. The so called tertian aetivo-autumnal variety may be seen at the proper stage in all cultures grown from merozoites. The form and appearance of the same culture of plasmodia may vary greatly under different conditions which are not necessarily destructive to the parasites. Their generation period may vary from thirty hours (aetivo-autumnal) to four days (tertian), as a result of variation in the temperature at which they were cultivated. Sexual parasites grow in the cultures and are more resistant to unfavorable conditions than schizonts, often living several days after the latter die out. Forms suggesting parthenogenesis have been observed.
间日疟原虫和恶性疟原虫的无性生殖周期已在人血中体外培养。寄生虫也在无氯化钙的洛氏溶液和腹水存在的情况下在红细胞中生长。寄生虫在红细胞内生长，没有证据表明它们可以在这些细胞外生长。寄生虫在体外几分钟内就被正常的人血清或我们测试过的所有血清变种破坏。这一事实，以及在所有阶段的生长中的寄生虫的许多观察结果，显然在红细胞内，使得细胞外发育的想法站不住脚。白细胞吞噬并破坏在体外生长的疟原虫，只有当寄生虫从其红细胞囊中逸出，或者当后者穿孔或变得通透时才会发生。间日疟原虫和恶性疟原虫的连续几代已通过从培养物中去除白细胞并在适当的间隔时间移植到新鲜的红细胞和血清中来体外培养。体外培养的间日疟原虫和恶性疟原虫的无性生殖周期与体内生长的同一周期没有区别。虽然我们已经获得了一些关于其完成的可能性的证据，但性周期尚未被培养。已经毫无疑问地证明间日疟原虫和恶性疟原虫是不同的、独特的物种。当在相同的培养介质中并在完全相同的条件下生长时，它们仍然是不同的。在 29 个蚊媒疟原虫的培养物中，观察到了许多形态和大小，从而提供了证据证明存在不同的蚊媒疟原虫变种。在所有从裂殖子生长的培养物中，都可以看到适当阶段的所谓间日疟原虫。在不同条件下，相同的疟原虫培养物的形态和外观可能会有很大的变化，而这些条件不一定对寄生虫有破坏性。它们的代时可能会从 30 小时（间日疟原虫）到 4 天（间日疟原虫）不等，这是由于培养温度的变化所致。有性寄生虫在培养物中生长，比裂殖体对不利条件更具抵抗力，裂殖体经常在后者死亡后存活数天。已经观察到了暗示孤雌生殖的形态。
