In vitro experiment for tick borne encephalitis virus transmitting across the blood brain barrier

Abstract:

[Objective] To understand the route and mechanism of tick borne encephalitis virus transmitting across the blood brain barrier, we established an in vitro blood brain barrier model, and studied the difference of the virus cultured from two different cell lines for transmitting across the blood brain barrier. [Methods] We used human brain microvascular endothelial cells (hCMEC/D3) to establish the vitro blood brain barrier model. First, we detected the infection and replication of tick borne encephalitis virus in hCMEC/D3 using real time PCR and plague assay. Then, we conducted the transmitting assay by adding tick borne encephalitis virus into the transwell inserts of the blood brain barrier model and detected virus titer leaking from the upper inserts into the bottom wells using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and plaque assay. Meanwhile, we added the THP-1 cells infected with tick borne encephalitis virus into the transwell inserts and observed the bottom wells under the optical microscope to confirm if the monocyte THP-1 could leak across the vito blood brain barrier. The virus titer leaked into bottom wells were detected by using qRT-PCR and plaque assay. The permeability change of blood brain barrier at different time post infection was tested by using Bovine Serum Albumin conjugated evens blue.[Results] We found that no replication of tick borne encephalitis virus in hCMEC/D3 cells, and tick borne encephalitis virus cultured in BHK-21 was unable to transmigrate across the blood brain barrier directly. However, the monocyte cell line THP-1 infected with tick borne encephalitis virus could cause its transmitting across the blood brain barrier and increase the permeability of the blood brain barrier, though THP-1 did not transmit across the vitro blood brain barrier directly.[Conclusion] Tick borne encephalitis virus can transmigrate across the blood brain barrier in assistance of monocyte THP-1 cells.