Lulo cell line derived from Lutzomyia longipalpis (Diptera: Psychodidae): a novel model to assay Leishmania spp. and vector interaction

Abstract

BackgroundLeishmania (Vianna) braziliensis, Leishmania (Leishmania) amazonensis and Leishmania (Leishmania) chagasi are important parasites in the scenario of leishmaniasis in Brazil. During the life cycle of these parasites, the promastigote forms adhere to the midgut epithelial microvillii of phlebotomine insects to avoid being secreted along with digestive products. Lulo cells are a potential model that will help to understand the features of this adhesion phenomenon. Here, we analyze the interaction between Leishmania spp. promastigotes and Lulo cells in vitro, specifically focusing on adhesion events occurring between three Leishmania species and this cell line.MethodsConfluent monolayers of Lulo cells were incubated with promastigotes and adhesion was assessed using both light microscopy and scanning electron microscopy.FindingsThe results indicate that species from the subgenera Leishmania and Viannia have great potential to adhere to Lulo cells. The highest adherence rate was observed for L. (L.) chagasi after 24 h of incubation with Lulo cells (27.3 ± 1.8% of cells with adhered promastigotes), followed by L. (L.) amazonensis (16.0 ± 0.7%) and L. (V.) braziliensis (3.0 ± 0.7%), both after 48 h. In the ultrastructural analysis, promastigote adherence was also assessed by scanning electron microscopy, showing that, for parasites from both subgenera, adhesion occurs by both the body and the flagellum. The interaction of Lulo cells with Leishmania (L.) chagasi showed the participation of cytoplasmic projections from the former closely associating the parasites with the cells.ConclusionsWe present evidence that Lulo cells can be useful in studies of insect-parasite interactions for Leishmania species.

Participation of heparin binding proteins from the surface of Leishmania (Viannia) braziliensis promastigotes in the adhesion of parasites to Lutzomyia longipalpis cells (Lulo) in vitro

“…longipalpis adult insects, a species which is commonly used in studies of interaction between parasite and insect [36]. Although Lulo cells have already been described as interacting more avidly with L. (L.) chagasi promastigotes of [14,37], we provide, in the present study, additional evidence that L. (V.) braziliensis has the ability to interact with Lulo cells. This is an interesting finding, as Lu.…”

“…The cells were seeded on coverlips to a final number of 2 x 10 5 cells per well and grown to semiconfluent monolayers prior to interaction assays with parasites [14]. …”

“…For example, Lulo cells, a cell lineage derived from Lutzomyia longipalpis , are a potential in vitro model to understand the features of the infection-related adhesion phenomena [14]. These models are suitable for analyzing the effects of interactions between surface molecules from both parasite (e.g., gp63, LPG, PPG etc.)…”

Leishmania development in sand flies: parasite-vector interactions overview

“…In agreement with this hypothesis, de Castro Cortes et al . have recently observed heparin binding proteins from the surface of Leishmania (Viannia) braziliensis promastigotes participating in the adhesion of parasites to L. longipalpis cell line in vitro [105,106]. However, the cell line can hardly mimmic highly differenciated midgut cells with microvilli.…”

Exploring the Association of Surface Plasmon Resonance with Recombinant MHC:Ig Hybrid Protein as a Tool for Detecting T Lymphocytes in Mice Infected withLeishmania (Leishmania) amazonensis

“…Recent studies by our research group, applying biosensing methods, proved that L. (V.) braziliensis promastigotes [17] and Trypanosoma cruzi epimastigotes and trypomastigotes [18] can bind to immobilized heparin, thereby, pointing to the presence of heparin receptors on the surface of these parasites.…”