Specificity of antibodies to Newcastle disease virus.

Specificity of antibodies to Victoria strain of Newcastle disease virus (NDV) found in infectious mononucleosis (IM) and other pathologic sera was investigated by agglutination of NDV-modified human O red blood cells, as well as by immunodiffusion and enzyme immunoassay with various preparations of the virus. These studies clearly demonstrated that the NDV antibodies are distinct from P-B or H-D antibodies. The unexpected observation that guinea pig kidney (GPK) tissues absorbed NDV antibodies allowed their classification into a group of 'GPK-positive' heterophile antibodies. The simultaneous occurrence of the NDV antibodies and H-D antibodies in IM and other diseases suggests the possibility that multiple new antigenic determinants, especially those of carbohydrate nature, may appear due to the alteration of self-antigens as a result of various pathologic processes.