Listeria monocytogenes Infection of Bat Pipistrellus nathusii Epithelial cells Depends on the Invasion Factors InlA and InlB

Abstract

L. monocytogenes is a widespread facultative intracellular pathogen. The range of natural hosts that supporting L. monocytogenes persistence in the environment has not been fully established yet. In this study, we were interested in the potential of L. monocytogenes to infect cells of bats, which are being increasingly recognized as a reservoir for microorganisms that are pathogenic to humans and domestic animals. A stable epithelial cell line was developed from the kidneys of Pipistrellus nathusii, a small bat widely distributed across Europe. The wild-type L. monocytogenes strain EGDe infected this cell line with an invasion efficiency of 0.0078 ± 0.0009%. Once it entered bat cells, L. monocytogenes doubled within about 70 minutes. When L. monocytogenes lacked either of the major invasion factors, InlA and InlB, invasion efficiency decreased by a factor of 10 and 25 respectively (p < 0.000001). The obtained results suggest that bat epithelial cells are susceptible to L. monocytogenes infection and that L. monocytogenes invasion of bat cells depends on the major invasion factors InlA and InlB. These results constitute the first report on in vitro studies of L. monocytogenes infection in bats.

Listeria monocytogenes Invasion Into Sheep Kidney Epithelial Cells Depends on InlB, and Invasion Efficiency Is Modulated by Phylogenetically Defined InlB Isoforms

“…To visualize the death of neighboring host cells, we applied a standard macroscopic plaque assay using neutral red solution staining ( Sun et al, 1990 ). Nevertheless, although this approach worked well in different cell models, including mouse L2 cell fibroblasts, human intestinal HT-29 cells, and bat kidney epithelial cells ( Sun et al, 1990 ; Roche et al, 2001 ; Povolyaeva et al, 2020 ), the standard assay did not reveal visible plaques in the shKEC monolayer even after 10 days of incubation (data not shown). To resolve the question of whether L. monocytogenes could move from cell to cell, we studied infected shKEC monolayers by using light microscopy.…”

“…InlB is one of major invasion factors that provides L. monocytogenes invasion into epithelial cells via interactions with its target receptor c-Met ( Bierne and Cossart, 2002 ). InlB was shown to provide species-specific interactions of L. monocytogenes with the guinea pig, rabbit, and bat cells ( Khelef et al, 2006 ; Povolyaeva et al, 2020 ). The diagram of the structure of c-Met with the indication of the main domains is shown ( Figure 6A ).…”

“…Cell lysates of L. monocytogenes were boiled for 10 min, separated on 10% SDS–PAGE and transferred onto PVDF membrane. InlB was visualized with polyclonal primary anti-InlB antibodies were obtained as described earlier ( Povolyaeva et al, 2020 ) and donkey anti-rabbit IgG HRP-labeled antibodies (Abcam, London, United Kingdom).…”

“…The statistical significance of competition experiments relative to a corresponding positive control is shown (***p < 0.001). (B) Immunoblotting analysis of membrane-bound proteins of the EGDeΔinlB::InlBCC9, EGDe, and EGDeΔinlB strains.InlB was visualized with polyclonal primary anti-InlB antibodies were obtained as described earlier(Povolyaeva et al, 2020). GAPDH of Listeria monocytogenes was used as a control.…”

Sensitivity of Pipistrellus Nathusii Kidney Diploid Cell Strain to Viruses of Rhabdoviridae, Reoviridae, Bunyaviridae and Paramixoviridae Families

“…Earlier, our group developed a stable epithelial cell line from the kidneys of P. nathusii (PKDCL) [9]. In another study, this diploid cell line demonstrated the ability to maintain reproductions of Bluetongue virus, Rift Valley fever, Lumpy skin disease virus and Myxoma virus [10].…”