the present invention includes a method of delivering a therapeutic agent into and across an endothelial cell in a subject in need thereof , comprising : attaching to a t cell receptor 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 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 .