Expression of CD137 on Hodgkin and Reed-Sternberg cells inhibits T-cell activation by eliminating CD137 ligand expression.

Hodgkin lymphoma is caused by a minority population of malignant Hodgkin and Reed-Sternberg (HRS) cells that recruit an abundance of inflammatory cells. The long-term survival of HRS cells among the vast majority of immune cells indicates that they have developed potent immune escape mechanisms. We report that the TNF receptor family member CD137 (TNFRSF9) is expressed on HRS cells, while normal B cells, from which HRS cells are most often derived, do not express CD137.

CD137 is expressed on blood vessel walls at sites of inflammation and enhances monocyte migratory activity.

The cytokine receptor CD137 is a member of the TNF receptor family and a potent T cell costimulatory molecule. Its ligand is expressed on antigen presenting cells as a transmembrane protein and it too can deliver signals into the cells it is expressed on (reverse signaling). In monocytes, immobilized CD137 protein induces activation, prolongation of survival and proliferation.