CP and choroid plexus papilloma: There is evidence that during an infection Nm interacts with the basolateral side of CP epithelial cells [5,6] and in an in vitro model of the BCSFB based on human choroid plexus papilloma (HIBCPP) cells Neisseria can enter and transmigrate across these CP epithelial cells by invasion from the physiologically relevant basolateral blood side [7].