Tumor necrosis factor receptor superfamily, member 4 (TNFRSF4), also known as CD134 and OX40 receptor, is a member of the TNFR-superfamily of receptors which is not constitutively expressed on resting naïve T cells, unlike CD28.
The TNFRSF4 gene encodes for a receptor that belongs to the tumor necrosis factor receptor family. Unlike CD28, this receptor is not constantly present on the surface of resting, new T cells.