Global Health and Tropical Medicine,GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL,Rua Junqueira 100, 1349-008 Lisbon,Portugal.
Fundação Oswaldo Cruz,Instituto Gonçalo Moniz,Salvador, BA,Brazil.
Parasitology. 2019 Apr;146(5):580-587. doi: 10.1017/S0031182018001993. Epub 2018 Nov 29.
The clinical manifestation and course of Leishmania infections depend on factors such as species, virulence and host-immunity. Although trypanosomatids are considered to have clonal propagation, genetic hybridization has produced successful natural hybrid lineages. Hybrids displaying strong selective advantages may have an impact on pathogenesis and the eco-epidemiology of leishmaniasis. Thus, characterization of phenotypic properties of Leishmania hybrids could bring significant insight into the biology, infectivity, pathogenicity and transmission dynamics of these atypical strains. The present study focuses on phenotypic features and survival capacity of Leishmania infantum/Leishmania major hybrid isolates as compared with representative putative parental species, L. infantum and L. major. In vitro assays (growth kinetics, susceptibility to different conditions) and in vivo infection (parasite detection and histopathological alterations) showed that hybrids present higher growth capacity and decreased susceptibility to reactive oxygen species. Furthermore, evaluation of infected spleen tissue suggests that hybrids induce a stronger immune reaction than their putative parents, leading to the development of white pulp hyperplasia in B-lymphocyte compartments. Overall, these hybrids have shown high plasticity in terms of their general behaviour within the different phenotypic parameters, suggesting that they might have acquired genetic features conferring different mechanisms to evade host cells.
利什曼原虫感染的临床表现和病程取决于物种、毒力和宿主免疫等因素。虽然无鞭毛体被认为是无性繁殖的，但遗传杂交已经产生了成功的自然杂交谱系。具有较强选择优势的杂种可能会影响利什曼病的发病机制和生态流行病学。因此，对利什曼原虫杂种表型特性的表征可以深入了解这些非典型菌株的生物学、传染性、致病性和传播动力学。本研究集中于利什曼原虫/利什曼原虫杂种分离株与代表性假定亲种（L.infantum 和 L.major）的表型特征和存活能力。体外试验（生长动力学、对不同条件的敏感性）和体内感染（寄生虫检测和组织病理学改变）表明，杂种具有更高的生长能力和降低对活性氧的敏感性。此外，对感染脾脏组织的评估表明，杂种比其假定亲本诱导更强的免疫反应，导致 B 淋巴细胞区白髓增生。总的来说，这些杂种在不同表型参数的一般行为方面表现出很高的可塑性，这表明它们可能获得了赋予其逃避宿主细胞的不同机制的遗传特征。
