Mouse LSECtin as a model for a human Ebola virus receptor

Pipirou, Zoi; Powlesland, Alex S; Steffen, Imke; Pöhlmann, Stefan; Taylor, Maureen E; Drickamer, Kurt

The mRNA for LSECtin is found in a restricted pattern, with the primary sites of expression being sinusoidal endothelial cells in liver and lymph nodes (Liu et al. 2004) , although expression has also been reported in suitably stimulated dendritic cells and macrophages in vitro and in the Kupffer cells (Domínguez-Soto et al. 2007; Domínguez-Soto et al. 2009 ). Unlike many glycan-binding receptors, LSECtin does not appear to function in clathrin-mediated endocytosis (Gramberg et al. 2008; Powlesland et al. 2008) , although it can undergo antibody-induced internalization in myeloid cells (Domínguez-Soto et al. 2007) . Several biological functions for LSECtin mediated by its ability to interact with specific glycans have been investigated. In vitro studies demonstrate that human LSECtin can provide a route for Ebola virus and SARS coronavirus infection of cells initiated by binding of LSECtin to glycans of the viral envelope glycoproteins (Gramberg et al. 2005; Domínguez-Soto et al. 2007; Powlesland et al. 2008) . Studies in mice indicate that mouse LSECtin is able to bind T cells through glycans on the CD44 T-cell surface marker (Tang et al. 2010) . This interaction leads to suppression of T-cell responses and knockout mice lacking LSECtin show increased sensitivity to liver damage mediated by T cells following acute injury, suggesting that LSECtin plays a role in protection of the liver from immune attack (Tang et al. 2009 ). Finally, it has been suggested that receptor expressed on myeloid cells could be involved in antigen capture and presentation (Domínguez-Soto et al. 2007) .