Leishmania enriettii: biochemical characterisation of lipophosphoglycans (LPGs) and glycoinositolphospholipids (GIPLs) and infectivity to Cavia porcellus

Abstract

BackgroundLeishmania enriettii is a species non-infectious to man, whose reservoir is the guinea pig Cavia porcellus. Many aspects of the parasite-host interaction in this model are unknown, especially those involving parasite surface molecules. While lipophosphoglycans (LPGs) and glycoinositolphospholipids (GIPLs) of Leishmania species from the Old and New World have already been described, glycoconjugates of L. enriettii and their importance are still unknown.MethodsMice peritoneal macrophages from C57BL/6 and knock-out (TLR2 −/−, TLR4 −/−) were primed with IFN-γ and stimulated with purified LPG and GIPLs from both species. Nitric oxide and cytokine production were performed. MAPKs (p38 and JNK) and NF-kB activation were evaluated in J774.1 macrophages and CHO cells, respectively.ResultsLPGs were extracted, purified and analysed by western-blot, showing that LPG from L88 strain was longer than that of Cobaia strain. LPGs and GIPLs were depolymerised and their sugar content was determined. LPGs from both strains did not present side chains, having the common disaccharide Gal(β1,4)Man(α1)-PO4. The GIPL from L88 strain presented galactose in its structure, suggestive of type II GIPL. On the other hand, the GIPL of Cobaia strain presented an abundance of glucose, a characteristic not previously observed. Mice peritoneal macrophages from C57BL/6 and knock-outs (TLR2 -/- and TLR4 -/-) were primed with IFN-γ and stimulated with glycoconjugates and live parasites. No activation of NO or cytokines was observed with live parasites. On the other hand, LPGs and GIPLs were able to activate the production of NO, IL-6, IL-12 and TNF–α preferably via TRL2. However, in CHO cells, only GIPLs were able to activate TRL2 and TRL4. In vivo studies using male guinea pigs (Cavia porcellus) showed that only strain L88 was able to develop more severe ulcerated lesions especially in the presence of salivary gland extract (SGE).ConclusionThe two L. enriettii strains exhibited polymorphisms in their LPGs and GIPLs and those features may be related to a more pro-inflammatory profile in the L88 strain.

The Biting Midge Culicoides sonorensis (Diptera: Ceratopogonidae) Is Capable of Developing Late Stage Infections of Leishmania enriettii

“…However, parasites inoculated into the noses grew very quickly, producing large, ulcerated, tumour-like lesions. We did not observe a self-healing process, as previously reported [ 37 , 42 , 43 ]. According to recent studies, parasites of the L .…”

“…The short nectomonads are responsible for forward migration and colonization of the stomodeal valve including production of promastigote secretory gel (PSG), which together with sand fly saliva are critical components for disease outcome and progress [ 35 , 36 ]. One area of interest for future investigation would be to see if midge saliva had disease exacerbating properties similar to those of sand fly saliva [ 37 ]. Localization of parasite masses on the SV and presence of metacyclic promastigotes is associated with Leishmania transmission in sand flies [ 38 , 39 ] and has been observed in Forcipomyia midges naturally infected with Leishmania sp.…”

“…Leishmania enriettii is known as a pathogen of guinea pigs causing tumour-like skin lesions. While some authors [ 41 , 42 ] reported metastatic spread of parasites to distant parts of the guinea pig body (eyelids, lips, feet and genitalia), others found parasites limited to the inoculation site [ 10 , 37 ]. The evolution of skin lesions caused by L .…”

“…The evolution of skin lesions caused by L . enriettii can be extremely fast within two weeks PI [ 42 ] and can be enhanced by addition of sand fly salivary gland extract to the inoculum [ 37 ]. In our study, disease manifestation differed between individuals and inoculation sites.…”

Lathosterol oxidase (sterol C5-desaturase) deletion confers resistance to amphotericin B and sensitivity to acidic stress inLeishmania major

“…The extracts were dried by N 2 evaporation, resuspended in 0.1 M acetic acid/0.1 M NaCl, and applied to a column of phenyl-Sepharose (2 mL), equilibrated in the same buffer. LPG and GIPLs were eluted using solvent E (77).…”