Multinucleate host cells induced by Vittaforma corneae (Microsporidia)

Abstract

Abstract. The microsporidium Vittaforma corneae (Shadduck, Meccoli, Davis et Font, 1990) develops within the target cell cytoplasm. In the present study, green monkey kidney (E6) cells infected at 30°C, 35°C or 37°C with V. corneae developed enlarged multinucleate structures of up to 200 µm in any horizontal dimension made up either of a single cell or of multiple fused cells. A number of epithelial cell types (SW-480, HT-29, Caco-2 and HCT-8) were infected with V. corneae but did not induce the same highly organized structures, suggesting that for the structure to develop, the host cell must be capable of continued mitosis, and not be differentiated or be detaching from the surface matrix. Live cell imaging of infected E6 cells revealed large, multinucleate infected cells characterized by a central focus from which radiated parasite stages and host cell mitochondria. Immunocytochemistry identifying γ and α tubulin suggested that a single centrally-located microtubule organizing centre governed the distribution of parasite stages and host cell organelles, with mitochondria and parasites being eventually transported towards the periphery of the structure. Whole cell patch clamp analysis of infected cells indicated an average five-fold increase in total membrane capacitance, consistent with an enlarged single cell. Scanning electron microscopy revealed cell-like protrusions around the periphery of the structure with the intervening space being made up of parasites and cell debris. Clearly in the case of V. corneae-infected E6 cells the parasite-host cell relationship involves subverting the host cell cytoskeleton and cell volume control, providing the parasite with the same protected niche as does a xenoma.

Development of the microsporidian parasite, Loma salmonae, in a rainbow trout gill epithelial cell line (RTG-1): evidence of xenoma development in vitro

“…One study of a human microsporidian did elicit some xenomalike growth within E6 cells (Leitch et al 2005). One study of a human microsporidian did elicit some xenomalike growth within E6 cells (Leitch et al 2005).…”

Animal cell cultures in microsporidial research: their general roles and their specific use for fish microsporidia

“…Treatment of mouse macrophages in primary culture but not of a mouse macrophage cell line with interferon gamma (IFNγ) inhibited E. cuniculi replication (Jelinek et al 2007). On the other hand, the reorganization of microbutules and induction of multinucleation in green monkey cell line E6 by V. cornea might be away for the parasite to be protected from the host immune response (Leitch et al 2005). To date, this has only been documented in vitro.…”

Characterization of a Divergent Sec61β Gene in Microsporidia

“…Determining between the two is of interest because the secretion pathway is likely a major route for parasite−host interactions in this system: any protein secreted by a microsporidian is actually released into the parasitophorous vacuole or the host cytoplasm, and infection by many microsporidia is known to produce a dramatic effect on the organisation and activity of the host cell. [16][17][18] To determine if microsporidian Sec complexes include Sec61β, we used a genome sequence survey of a second microsporidian species, Antonospora locustae, and based on genomic position, secondary structure analysis, as well as localisation and complementation in yeast, found that a highly divergent form of Sec61β is indeed present in both microsporidia.…”