An insight into the ligand-receptor interactions involved in the translocation of pathogens across blood-brain barrier

Traversal of pathogen across the bloodbrain barrier (BBB) is an essential step for central nervous system (CNS) invasion. Pathogen traversal can occur paracellularly, transcellularly, and/or in infected phagocytes (Trojan horse mechanism). To trigger the translocation processes, mainly through paracellular and transcellular ways, interactions between protein molecules of pathogen and BBB are inevitable. Simply, it takes two to tango: both host receptors and pathogen ligands. Underlying molecular basis of BBB translocation of various pathogens has been revealed in the last decade, and a plethora of experimental data on proteinprotein interactions has been created. This review compiles these data and should give insights into the ligandreceptor interactions that occur during BBB translocation. Further, it sheds light on cell signaling events triggered in response to ligandreceptor interaction. Understanding of the molecular principles of pathogenhost interactions that are involved in traversal of the BBB should contribute to develop new vaccine and drug strategies to prevent CNS infections.