sentences:  They used this cell line to study how leafhopper cells interacted with "S. citri" cells "in vivo".After incubation of beet leafhopper cells with "S. citri cells", researchers used an electron microscope to see how cell lines interact.They found that "S. citri cells" were pressed against the cell membranes of "C. tenellus" cells, and they also observed invaginations of the cell membrane.