Abstract
Serological reactions between anti-human placental tissue antiserum and 584 human sera from patients of various diseases and conditions have been tested using the micro-Ouchterlony method. Relatively high incidence of positive reaction was noted with cases of malignant tumours (57.5%), leukaemia (63.6%), pregnancy (77.8%), myocardial infarction (41.2%), and hepato-biliary diseases (43.3%). One of the most important and interesting characters of this test is the wide variety of neoplasms which showed a positive reaction. The active factor was located at β-area by immunoelectrophoresis, except in the case of pregnancy. Antigen analysis using a double diffusion method on agar plate showed quite a simila1ity between umbilical cord and placental tissue extracts, the active components of which were tentatively named umbilico-placental antigens.
