We generated a monodonal antibody (MAb), designated LN-6, directed against human vimentin, which retains its immunoreactivity in B5-flxed, paraffin-embedded tissues. Like other anti-vimentin MAb, LN-6 was found to be reactive with a wide spectrum of human sarcomas and normal cells of mesenchymal derivation. However, unlike other similar reagents, LN-6 was unreactive with normal and malignant hu
A monoclonal antibody, designated BM-1, which is reactive in B5 formalin-fixed, paraffin-embedded tissues, has been generated against a cytoplasmic and nuclear antigen expressed in human myeloid precursor cells and derived leukemias. Using the avidin-biotin-complex immunoperoxidase procedure, BM-1 was found to stain selectively myeloid precursor cells in normal bone marrow and mature granulocytes in the blood. In a screen of 26 normal adult and fetal human organs fixed in B5 formalin, BM-1 was negative in all nonhematopoietic tissues with the exception of tissue granulocytes and scattered cells in the peripheral cortex of the thymus. Likewise a screen of 30 solid tumor cell lines including a spectrum of carcinomas, sarcomas, and neural-derived tumors was negative. BM-1 was also negative with 21 T and B cell lymphomas and 11 Hodgkin's disease tumors. A preliminary study of tumors of the hematopoietic system revealed that BM-1 was reactive with M2 and M3 acute myelogenous leukemias (AML), chronic myelogenous leukemias (CML) and myelomonocytic leukemias, and granulocytic sarcomas. M1, M4, M5, and M6 AML clot preparations were negative in this study, indicating that BM-1 may have a role in the histopathologic diagnosis of myelogenous leukemia. Myeloid leukemic cell lines HL-60, ML-2, KG1, and TPH-1-O showed BM-1 nuclear and/or cytoplasmic reactivity in a subpopulation of cells, but erythroid and lymphoid leukemias and all lymphoma cell lines were negative. Immunoperoxidase studies of a panel of fetal tissues showed BM-1 positive cells in the peripheral cortex of the thymus and portal myelopoietic regions of the liver at 18 weeks gestation. Finally, DNA-cellulose and solid phase radioimmunoassay (RIA) techniques developed in our laboratory demonstrate that the BM-1 antigenic domain is reactive only after binding to eukaryotic but not prokaryotic single- or double-stranded DNA. Immunoblot techniques using a DNA-cellulose purified protein sample revealed that BM-1 recognizes a 183 kD protein. These studies indicate that BM-1 is recognizing a myeloid-specific antigen that, because of its DNA binding characteristics, may have an important role in the differentiation of myeloid cells at the molecular level.
Two monoclonal antibodies (LN-4, LN-5) reactive to human macrophages in B5 formalin-fixed, paraffin-embedded tissue sections have been produced by using deparaffinized cell extracts of peripheral blood mononuclear cells. Both monoclonal antibodies were initially identified on paraffin- embedded sections of hyperplastic lymph nodes by using the immunoperoxidase staining procedure. Specificity screens on normal human tissues show that LN-4 and LN-5 stain the cytoplasm of macrophages and histiocytes in hematopoietic organs including Kupffer's cells of the liver and Langerhans' cells of the skin. LN-4 also showed strong positivity with acini of the stomach, whereas LN-5 was positive with mantle zone B lymphocytes of the lymph node and spleen, spermatogonia, and chief cells of the stomach. Both antibodies were strongly reactive with cases of true histiocytic lymphoma but, except for infiltrating macrophages, were entirely negative in Hodgkin's disease and non-Hodgkin's lymphomas. In all cases of nodular sclerosis Hodgkin's disease, LN-4 was positive in macrophagelike cells present in the collagen bands surrounding the Hodgkin's lesions. Both monoclonal antibodies were also positive in macrophages and histiocytes present in a variety of benign lymphoid lesions including persistent generalized lymphadenopathy, Gaucher's disease, sinus histiocytosis, and dermatopathic lymphadenopathy. Because of their specificity for human macrophages, and their ability to stain B5-fixed, paraffin-embedded tissues, LN-4 and LN-5 are important new reagents for the diagnosis and classification of malignant and benign histiocytic lesions.
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