[Cell hybridization: a monoclonal marker as a diagnostic help in haematology and oncology (author's transl)]

This is a communication on the introduction of the first monoclonal marker at Graz University Medical School. Human peripheral blood mononuclear cells were used for immunisation of BALB/c mice by injecting 4,5 X 10(6) cells s. c. Boosting consisted of i.p. injection of 5 X 10(6) cells 4 times in monthly intervals. Spleen cells were taken 4 days after the last boost, fused with NS-1 myeloma cells, using PEG as fusogenic agent. After growth in HAT selective medium, antibody secreting clones were identified by testing the supernatants. Cultures with activity against lymphocytes were closed on normal BALB/C peritoneal cell feeder layers. One of them secreted IgG 1 with strong activity against all lymphoid cells and was named HLy D 1. Further testing showed activity with band cells, polymorphs, eosinophils, macrophages but not with tissue sections from anaplastic undifferentiated cancers and erythroid leukaemias. Since he was named H Le D 1 and introduced for differentiating rare undifferentiated carcinomas from malignant tumors of the lymphoid system.