Successively, other authors also analyzed the anti-cytomegalovirus activity of lactoferrin in vivo in rat models with and without immune suppression, demonstrating that treatment with lactoferrin (intravenously) was helpful when infection was initiated with cell-free virus, but not with virus infected leukocytes and that lactoferrin exerted its effects via inhibition of cell entry rather than via stimulation of the immune system [59]. This evidence concerns the gene LTF and infection.