Functional validation of the simplified in vitro 3D Co-culture based BBB model.

Various methods of generating 2D and 3D in vitro blood-brain barrier (BBB) models have previously been published with the objective of developing therapeutics for brain diseases. In general, published methods including our published method demonstrate that in vivo-like semi-permeable barrier can be generated. To further verify that an in vitro BBB model closely represents BBB, functional validation is required. Here, we functionally validate our in vitro 3D BBB model using rituximab as a representative therapeutic antibody and previously published anti-TfR (transferrin receptor) antibodies as representative BBB-penetrating antibodies. We demonstrate that our BBB model can efficiently block rituximab while allowing receptor-mediated transcytosis (RMT) of anti-TfR antibodies. In addition, we showed that RMT efficacy of anti-TfR antibodies with different binding affinity can be displayed using our BBB model. In conclusion, this demonstrates that our BBB model functionally mimics the BBB as well as having BBB-like physical properties, further establishing our BBB model as a screening tool for discovery and development of therapeutics for brain diseases.