Comparative analysis of neuroinvasion by Japanese encephalitis virulent and vaccine strains in anin cellulomodel of human blood-brain barrier

Abstract

27Japanese encephalitis virus (JEV) is the major cause of viral encephalitis 28 in South East Asia. It has been suggested that JEV gets access to the central 29 nervous system (CNS) as a consequence of a preceding inflammatory process 30 which leads to the blood-brain barrier (BBB) disruption and viral neuroinvasion. 31However, what happens at early times of JEV contact with the BBB is poorly 32 understood. In the present work, we evaluated the ability of both a virulent and 33 a vaccine strain of JEV (JEV RP9 and SA14-14-2, respectively) to cross an in 34 cellulo human BBB model consisting of hCMEC/D3 human endothelial cells 35 cultivated on permeable inserts above SK-N-SH human neuroblastoma cells. 36Using this system, we demonstrated that both JEV RP9 and SA14-14-2 are 37 able to cross the BBB without disrupting it at early times post-addition. 38Furthermore, this BBB model was able to discriminate between the virulent RP9 39 and the vaccine SA14-14-2 strains, as demonstrated by the presence of almost 40 10 times more RP9 infectious particles that crossed the BBB than SA14-14 41 particles at a high MOI. Besides contributing to the understanding of early 42 events in JEV neuroinvasion, this in cellulo BBB model represents a suitable 43and useful system to study the viral determinants of JEV neuroinvasiveness and 44 the molecular mechanisms by which this flavivirus crosses the BBB at early 45 times of neuroinvasion. 46 47 48 49 50