Isolation of hemagglutination-defective mutants for the analysis of the sialic acid binding activity of transmissible gastroenteritis virus

The surface protein S of transmissible gastroenteritis virus (TGEV) has a sialic acid binding activity that enables the virus to agglutinate erythrocytes. A protocol is described that has been successfully applied to the isolation of hemgglutination-defective mutants. The potential of these mutants for the characterization of the sialic acid-binding site and the function of the binding activity is discussed.