Adeyemi Olumide, Osuntoki Akinniyi, Magbagbeola Olubunmi, Abdel Hamid Muzamil Mahdi, Elaagip Arwa, Mueller Ann-Kristin, Ibrahim Muntaser
Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Lagos, Nigeria.
Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan.
PLoS One. 2025 Mar 19;20(3):e0319901. doi: 10.1371/journal.pone.0319901. eCollection 2025.
Previous cell culture systems using various human hepatoma cell lines established that the intra-hepatic stages of Plasmodium falciparum could be studied ex vivo. However, only one of these culture systems yielded infective merozoites that subsequently completed the parasite's life cycle outside a human host. We hypothesized that a major limitation is the use of laboratory-adapted P. falciparum blood stages for sporozoites generation. Plasmodium falciparum sporozoites were generated by membrane-feeding of gametocyte-infected blood samples from hospital patients to Anopheles arabiensis. Subsequently, cultured HepG2 cells were infected with the sporozoites. From 6 days post-sporozoite inoculation, liver merozoites could be harvested from the cell supernatants. When co-cultured with O + erythrocytes, these merozoites established a blood infection and yielded erythrocytic stage parasites that re-infected erythrocytes. To confirm that the erythrocytic parasites generated were P. falciparum, RNA expressed by the erythrocytic parasites was isolated and used as control in microarray analysis against RNA expressed by irradiated erythrocytic parasites; subsequently, P. falciparum genes were identified. The cultured HepG2 cells permitted the full intra-hepatic maturation of P. falciparum parasites from natural isolates. Infective merozoites were yielded which gave rise to the erythrocytic stage P. falciparum post-infection into O + erythrocytes. The full intra-hepatic maturation of the naturally isolated P. falciparum parasites in a HepG2 cell culture system is possible. This finding has important implications for malaria research and vaccine development.
先前使用各种人类肝癌细胞系的细胞培养系统证实，恶性疟原虫的肝内阶段可以在体外进行研究。然而，这些培养系统中只有一个产生了有感染性的裂殖子，随后这些裂殖子在人类宿主之外完成了寄生虫的生命周期。我们推测一个主要限制是使用实验室适应的恶性疟原虫血液阶段来产生子孢子。通过将医院患者感染配子体的血样膜饲给阿拉伯按蚊来产生恶性疟原虫子孢子。随后，用这些子孢子感染培养的HepG2细胞。在接种子孢子后6天，可以从细胞上清液中收获肝裂殖子。当与O+红细胞共培养时，这些裂殖子建立了血液感染，并产生了再次感染红细胞的红细胞期寄生虫。为了确认产生的红细胞期寄生虫是恶性疟原虫，分离了红细胞期寄生虫表达的RNA，并将其用作针对经辐照的红细胞期寄生虫表达的RNA进行微阵列分析的对照；随后，鉴定了恶性疟原虫基因。培养的HepG2细胞允许天然分离株的恶性疟原虫寄生虫在肝内完全成熟。产生了有感染性的裂殖子，这些裂殖子在感染O+红细胞后产生了红细胞期恶性疟原虫。在HepG2细胞培养系统中天然分离的恶性疟原虫寄生虫在肝内完全成熟是可能的。这一发现对疟疾研究和疫苗开发具有重要意义。
