Tetraspanin CD53 Promotes Lymphocyte Recirculation by Stabilizing L-Selectin Surface Expression
Maria C. Demaria, Louisa Yeung, Rens Peeters, Janet L. Wee, Masa Mihaljcic, Eleanor Livingston Jones, Zeyad Nasa, Frank Alderuccio, Pamela Hall, Brodie C. Smith, Katrina J. Binger, G J Hämmerling, Hang Fai Kwok, Andrew J. Newman, Ann Ager, Annemiek B. van Spriel, Michael J. Hickey, Mark D. Wright
Abstract
Tetraspanins regulate key processes in immune cells; however, the function of the leukocyte-restricted tetraspanin CD53 is unknown. Here we show that CD53 is essential for lymphocyte recirculation. Lymph nodes of Cd53−/− mice were smaller than those of wild-type mice due to a marked reduction in B cells and a 50% decrease in T cells. This reduced cellularity reflected an inability of Cd53−/− B and T cells to efficiently home to lymph nodes, due to the near absence of L-selectin from Cd53−/− B cells and reduced stability of L-selectin on Cd53−/− T cells. Further analyses, including on human lymphocytes, showed that CD53 stabilizes L-selectin surface expression and may restrain L-selectin shedding via both ADAM17-dependent and ADAM17-independent mechanisms. The disruption in lymphocyte recirculation in Cd53−/− mice led to impaired immune responses dependent on antigen delivery to lymph nodes. Together these findings demonstrate an essential role for CD53 in lymphocyte trafficking and immunity.