Techniques to study phagocytosis and uptake of Leishmania tarentolae by J774 macrophages

Leishmania tarentolae as an Antigen Delivery Platform: Dendritic Cell Maturation after Infection with a Clone Engineered to Express the SARS-CoV-2 Spike Protein

“…The percentage of infected DCs (infection rate) and the average number of parasites in each infected cell after 4 h of incubation were calculated and corresponded, respectively, to 43% and 2.74 for Lt-wt and 40% and 2.84 for Lt-spike. As reported in other studies (e.g., [ 18 ]), after 48 h, parasites no longer survived intracellularly: only a few amastigotes, partially degraded, were visible inside the cells with an infection rate of about 20% ( Supplementary Figure S3 ). The presence of the spike protein on the parasite L. tarentolae , inside the DCs, was verified through an immunofluorescence assay ( Figure 4 ; Supplementary Figure S4 ); Figure 4 shows that the spike protein was maintained at the surface (panel A) and in the cytosol of the protozoan (panel B), also after the internalization by the DCs.…”

“…In addition, similarly to BCG, L. tarentolae has also been manipulated for the expression of proteins from pathogenic Leishmania species, as well as from viruses, and tested as a living vaccine vehicle in murine models (e.g., [ 12 , 13 , 14 , 15 , 16 , 17 ]). A major feature that makes this microorganism interesting as a potential vaccine vehicle is that, upon its inoculation into mammalian tissues, it is expected to target DCs and other phagocytic cells [ 11 , 18 ]. This assumption is based on well-established knowledge concerning the biology of Leishmania species infecting humans and dogs, whose major niche for survival and replication is represented by phagocytic myeloid cells, including DCs, mainly in secondary lymphoid tissues [ 19 ].…”

Antimicrobial Peptides (AMP) in the Cell-Free Culture Media of Xenorhabdus budapestensis and X. szentirmaii Exert Anti-Protist Activity against Eukaryotic Vertebrate Pathogens including Histomonas meleagridis and Leishmania donovani Species

“…Leishmania donovanii, and T. cruzi, using both the native (i.e., centrifuged and sterilefiltered) and heat-sterilized (i.e., centrifuged, sterile-filtered, and autoclaved) CFCMs of liquid cultures of three species of anti-microbial-producing EPB strains, EMA, EMC, and EMK (Xenorhabdus budapestensis nov. DSM16342(T)) [28], X. szentirmaii nov. DSM16338(T)) [28], and X. innexii nov. DSM16337(T) [8,28,29] were bioassayed with promastigotes and epimastigotes of Leishmania amazonensis and T. cruzi (Brazil strain), respectively, as well as on clinical isolates of Gram-positive bacteria (methicillin-sensitive and -resistant Staphylococcus aureus) and Gram-negative bacteria (Francisella novicida, E. coli, Salmonella typhimurium, and P. aeruginosa), and with the yeast, Candida albicans. The J774 murine macrophage cells served as a control for measuring the general eukaryotic cytopathogenicity of the CFCMs [68] (see below and Table 1 for additional details). The bioassays were extended to clinical pathogenic protozoa using previously described routine methods [95]).…”

Leishmania tarentolae: a vaccine platform to target dendritic cells and a surrogate pathogen for next generation vaccine research in leishmaniases and viral infections

“…However, several genes possibly associated with virulence are lacking in L. tarentolae, compared to pathogenic Leishmania species [67], which is reassuring in relation to safety issues. Third, current evidence indicates that L. tarentolae is not pathogenic to mammals, while still being capable of infecting macrophages and DCs, reaching the amastigote state [41,44,68]. Finally, the evidence for a circulation of L. tarentolae in dogs, and the absence of any evidence for its association with pathological outcomes, further emphasizes the potential utility of this parasite in anti-Leishmania vaccination (see [11] and section on L. tarentolae natural history and the evidence of infectivity in mammalian hosts).…”