Moesin: a cell membrane protein linked with susceptibility to measles virus infection.

Measles virus is a highly contagious virus causing acute and persistent diseases in man, the receptor of which is still not well characterized. We have isolated a monoclonal antibody (mAb), designated mAb 119, which specifically inhibits measles virus infection of susceptible cell lines in a dose-dependent manner. This antibody precipitates a protein with an apparent molecular mass of 75 kDa from 125I surface-labeled cells and its epitope is present on human peripheral blood mononuclear cells, human cell lines, and the African green monkey cell line Vero. Affinity chromatography of detergent-solubilized cell membrane proteins over a Sepharose column with covalently bound mAb 119 led to the partial purification of the 75-kDa protein. Preincubation of measles virus with this affinity-purified protein inhibited measles virus infection dose dependently. Amino acid microsequencing of this protein revealed its identity with the human membrane-organizing extension spike protein moesin, a protein intra- and extracellularly associated with the plasma membrane of cells. Subsequently, an antibody raised against purified moesin (mAb 38/87) was also found to specifically inhibit measles virus infection of susceptible cells and confirmed our data obtained with mAb 119. Our data suggest that moesin is acting as a receptor for measles virus.