Trans-endocytosis of CTLA-4

Trans-endocytosis of CTLA-4 The minimal expression of CTLA-4 on the surface of T cells is due to its own highly endocytotic properties, which allow it to continuously circulate at the cell membrane and inside the cell. In addition to competing with CD28 for the binding of CD80/CD86 molecules, CTLA-4 swallows both molecules into the cell interior, resulting in a reduction of CD80/CD86 on the surface of APCs.