The ALD-A from rabbit muscle was employed to immunize BALB/c mice. After hybridation and selection, five hybridomas secreting high titer anti-ALD-A monoclonal antibodies were prepared, among which the antibody from hybridoma E10 was found to be IgM. It was also found that this antibody did not reacted with normal human liver, spleen, lung, stomach and colon tissues but reacted weakly with normal human muscle. On the other hand, the human hcpatocellular carcinoma tissues were stained by PAP whate-ver the sera of these patients were AFP positive or negative. The results suggest that monoclonal antibodies directed against ALD-A might have potential application in diagnosis of hepatocellular carcinoma especially those with serum AFP negative.

Immunohistochemical localization of many sorts of tumor tissues from paraffin sections was studied using the ABC method with the monoclonal antibody secreted by the established two anti-osteosarcoma cell lines. It showed that the OS-McAb1 and OS-McAb2 had a negative reaction on the tested benign tumors and malignant tumors of epithelial tissue. Of the tested malignant tumors of mesenchyma, the antibodies had a positive reaction on some osteogenic sarcoma. They did not cross-react with various normal adult or fetal tissues, indicating that the OS-McAbs had a rather high specificity. They had a certain practical value in the immunopathologic diagnosis of malignant osteogenic tumors.