Dao Francois, Niangaly Amadou, Sogore Fanta, Wague Mamadou, Dabitao Djeneba, Goita Siaka, Hadara Aboubacrin S, Diakite Ousmaila, Maiga Mohamed, Maiga Fatoumata O, Cazevieille Chantal, Cassan Cecile, Talman Arthur M, Djimde Abdoulaye A, Marin-Menendez Alejandro, Dembélé Laurent
Malaria Research and Training Center (MRTC), Université des Sciences, des Techniques et des Technologies de Bamako (USTTB), Bamako, Mali.
MIVEGEC, Université de Montpellier, CNRS, IRD, Montpellier, France.
PLoS Negl Trop Dis. 2025 Jan 6;19(1):e0012790. doi: 10.1371/journal.pntd.0012790. eCollection 2025 Jan.
Plasmodium malariae is the third most prevalent human malaria parasite species and contributes significantly to morbidity. Nevertheless, our comprehension of this parasite's biology remains limited, primarily due to its frequent co-infections with other species and the lack of a continuous in vitro culture system. To effectively combat and eliminate this overlooked parasite, it is imperative to acquire a better understanding of this species. In this study, we embarked on an investigation of P. malariae, including exploring its clinical disease characteristics, molecular aspects of red blood cell (RBC) invasion, and host-cell preferences. We conducted our research using parasites collected from infected individuals in Mali. Our findings revealed anaemia in most of P. malariae infected participants presented, in both symptomatic and asymptomatic cases. Regarding RBC invasion, quantified by an adapted flow cytometry based method, our study indicated that none of the seven antibodies tested, against receptors known for their role in P. falciparum invasion, had any impact on the ability of P. malariae to penetrate the host cells. However, when RBCs were pre-treated with various enzymes (neuraminidase, trypsin, and chymotrypsin), we observed a significant reduction in P. malariae invasion, albeit not a complete blockade. Furthermore, in a subset of P. malariae samples, we observed the parasite's capability to invade reticulocytes. These results suggest that P. malariae employs alternative pathways to enter RBCs of different maturities, which may differ from those used by P. falciparum.
三日疟原虫是人类疟疾寄生虫中第三大流行种类，对发病率有显著影响。然而，我们对这种寄生虫生物学的理解仍然有限，主要原因是它经常与其他种类共同感染，并且缺乏连续的体外培养系统。为了有效对抗和消除这种被忽视的寄生虫，更好地了解这个物种势在必行。在本研究中，我们对三日疟原虫展开了调查，包括探索其临床疾病特征、红细胞（RBC）入侵的分子方面以及宿主细胞偏好。我们使用从马里感染个体收集的寄生虫进行研究。我们的研究结果显示，在有症状和无症状的病例中，大多数感染三日疟原虫的参与者都出现了贫血症状。关于通过一种改进的基于流式细胞术的方法量化的红细胞入侵情况，我们的研究表明，所测试的七种针对已知在恶性疟原虫入侵中起作用的受体的抗体，均对三日疟原虫穿透宿主细胞的能力没有任何影响。然而，当红细胞用各种酶（神经氨酸酶、胰蛋白酶和糜蛋白酶）进行预处理时，我们观察到三日疟原虫的入侵显著减少，尽管并未完全阻断。此外，在一部分三日疟原虫样本中，我们观察到该寄生虫具有侵入网织红细胞的能力。这些结果表明，三日疟原虫采用替代途径进入不同成熟度的红细胞，这可能与恶性疟原虫所使用的途径不同。
