A monoclonal antibody specific for immature human hemopoietic cells and T lineage cells.

An anti-human monoclonal antibody (RFB-1) has been produced that reacts with a group of hemopoietic precursor cells in human bone marrow. These include terminal deoxynucleotidyl transferase-positive (TdT+) cells and myeloid colony-forming unit cells, functionally identifiable progenitor cells of the granulocytic-monocytic series. The expression of RFB-1 antigen on myeloid cells decreases as the cells become more mature; myeloblasts are weakly RFB-1+ but most promyelocytes are RFB-1-. RFB-1 also reacts with TdT+ thymic blast cells and cortical thymocytes but is unreactive with TdT- medullary thymocytes, although the majority of peripheral T cells are weakly RFB-1+. RFB-1 is the first anti-precursor cell reagent that labels human TdT+ cells in both the thymus and bone marrow as well as hemopoietic precursor cells but is unreactive with pre-B blasts and B lymphocytes.

Immuno-histological diagnosis of lymphoproliferative diseases by selected combinations of antisera and monoclonal antibodies.

Tissue sections of frozen biopsy specimens obtained from normal and hyperplastic human lymphoid tissues, 33 cases of non-Hodgkin lymphomas as well as various forms of immunoregulatory disorders (angioimmunoblastic and dermatopathic lymphadenopathy) were analysed in immunofluorescence tests (using red TRITC and green FITC double-labelling). A panel of antisera including well-characterized conventional reagents to immunoglobulin classes, T lymphoid and Ia-like antigens, and monoclonal antibodies was used. In selected cases the results were compared with the observations of membrane-marker staining on viable cells in suspension. the findings show that the immunological methods can give a very accurate analysis of the normal and malignant lymphoid cells, and can provide complementary information to conventional histology. The investigator can choose the reagent combinations which give answers to various specific questions: e.g. antisera to light chains establish the monoclonality of lymphomas, whilst staining combinations for human T and Ia-like antigens are particularly useful in various immunoregulatory disorders. Monoclonal antibodies will be particularly useful in various immunoregulatory disorders. Monoclonal antibodies will be particularly useful reagents for analysing the tissue distribution of lymphoid subpopulations and ancillary cells in tissue biopsy specimens.