Detection of Leishmania RNA Virus in Leishmania Parasites

Haroun Zangger (1) , Catherine Ronet (1) , Chantal Desponds (1) , F. Matthew Kuhlmann (2) , John Robinson (2) , Mary-Anne Hartley (1) , Florence Prevel (1) , Patrik Castiglioni (1) , Francine Pratlong (3, 4) , Patrick Bastien (5, 4) , Norbert Müller (6) , Laurent Parmentier (7) , Nancy Gore Saravia (8) , Stephen Beverley (2) , Nicolas Fasel (1)

1 UNIL - Université de Lausanne = University of Lausanne
2 Washington University School of Medicine in St. Louis
3 MIVEGEC - Maladies infectieuses et vecteurs : écologie, génétique, évolution et contrôle
4 CNR-L - Centre National de Référence des Leishmanioses [CHRU Montpellier]
5 MIVEGEC-BioGEPPE - Biologie, Génétique et Pathologie des Pathogènes Eucaryotes
6 Vetsuisse Faculty [Berne, Suisse]
7 Institute Central des Hopitaux Valaisans
8 CIDEIM - Centro Internacional de Entrenamiento e Investigaciones Medicas

Background Patients suffering from cutaneous leishmaniasis (CL) caused by New World Leishmania (Viannia) species are at high risk of developing mucosal (ML) or disseminated cutaneous leishmaniasis (DCL). After the formation of a primary skin lesion at the site of the bite by a Leishmania-infected sand fly, the infection can disseminate to form secondary lesions. This metastatic phenotype causes significant morbidity and is often associated with a hyper-inflammatory immune response leading to the destruction of nasopharyngeal tissues in ML, and appearance of nodules or numerous ulcerated skin lesions in DCL. Recently, we connected this aggressive phenotype to the presence of Leishmania RNA virus (LRV) in strains of L. guyanensis, showing that LRV is responsible for elevated parasitaemia, destructive hyper-inflammation and an overall exacerbation of the disease. Further studies of this relationship and the distribution of LRVs in other Leishmania strains and species would benefit from improved methods of viral detection and quantitation, especially ones not dependent on prior knowledge of the viral sequence as LRVs show significant evolutionary divergence.Methodology/Principal Findings This study reports various techniques, among which, the use of an anti-dsRNA monoclonal antibody (J2) stands out for its specific and quantitative recognition of dsRNA in a sequence-independent fashion. Applications of J2 include immunofluorescence, ELISA and dot blot: techniques complementing an arsenal of other detection tools, such as nucleic acid purification and quantitative real-time-PCR. We evaluate each method as well as demonstrate a successful LRV detection by the J2 antibody in several parasite strains, a freshly isolated patient sample and lesion biopsies of infected mice.Conclusions/Significance We propose that refinements of these methods could be transferred to the field for use as a diagnostic tool in detecting the presence of LRV, and potentially assessing the LRV-related risk of complications in cutaneous leishmaniasis.

Domaines: Maladies infectieuses; Parasitologie; Biochimie [q-bio.BM]

Haroun Zangger, Catherine Ronet, Chantal Desponds, F. Matthew Kuhlmann, John Robinson, et al.. Detection of Leishmania RNA Virus in Leishmania Parasites. PLoS Neglected Tropical Diseases, 2013, 7, pp.e2006. ⟨10.1371/journal.pntd.0002006⟩. ⟨hal-02952522⟩