Antigenic Studies of Virus- and Trypsin-Treated Erythrocytes

Abstract
Rabbit antisera to normal, trypsin-treated, influenza virus-treated or Newcastle disease virus-treated human erythrocytes were shown to contain antibody for normal and treated red cells. Agglutinins specific for the various cell modifications were isolated by agglutinin-absorption procedures. The antigenic changes produced by the viruses and trypsin were found to be related but distinct. Each treatment was shown to remove some normal cell antigens, the alteration of normal cell surface components being most marked following treatment with Newcastle disease virus. Similar but less extensive modifications were demonstrated with virus-modified chicken erythrocytes. Striking cross-reactions were demonstrated between the antiserum to modified cells of each species and the treated heterologous red cells. NDV-modified cell agglutinin was separated from hemagglutinin-inhibiting antibody. Antiserum to NDV-treated cells was employed for the detection of modified erythrocytes in experimentally infected chickens and in an acquired hemolytic anemia patient.