The envelope glycoproteins and glycolipids of paramyxoviruses appear to be derived from the host cell plasma membrane during viral release (1, 2). Measles envelope glycoprotein spikes effect attachment of the virion to cell surfaces, thereby initiating either he-magglutination (HA) or infection (3,4). Most viruses which mature at the cell surface incorporate NANA from the plasma membrane (5-9). Myxoviruses and paramyxoviruses do not do so, because they contain virus-coded neuraminidase (10-12). NANA residues are detectable on purified vesicular stomatitis virus (VSV) (5, 8, 12, 13), avian tumor (7), rabies (9), Sindbis (14, 15) and Semliki Forest viruses (16), as well as on temperature-sensitive mutants of influenza virus type A which lack neuraminidase (17). In this report, we present evidence to show that measles virions likewise possess NANA residues which are involved in the adsorption of virus to the surface of cells.Materials and methods. VERO cells, obtained from the American Type Culture Collectio...