The present invention includes a method of delivering a therapeutic agent into and across an endothelial cell (EC) in a subject in need thereof, comprising: attaching to a T Cell receptor mimic (TCR mimic) an active agent to form a therapeutic agent； and administering to the subject the therapeutic agent in a pharmaceutically acceptable carrier, wherein the therapeutic agent effectively crosses the EC microvascular barrier. Furthermore, the present invention relates to methods of treating diseases (particularly neuronal diseases) or conditions comprising identifying a subject in need of such a treatment and administering to said subject a composition comprising a TCR mimic conjugated to an active agent.
