ABSTRACT
FMC3 and FMC29 are monoclonal antibodies which react with a 30,000 Dalton molecule expressed on the lymphocyte surface membrane. The molecule is a protein which does not appear to be N-glycosylated. The antigen, which is also expressed intracellularly, does not appear to be a marker of differentiation or maturation. Polyclonal cell populations, such as peripheral blood lymphocytes, show a bimodal distribution of surface antigen density, whilst monoclonal cell populations analysed quantitatively showed unimodal antigen density distributions. This suggests the antigen may be a clonal marker.
Subject(s)
Leukocytes/immunology , Antibodies, Monoclonal/immunology , Antigens, Surface/immunology , Antigens, Surface/isolation & purification , Cell Differentiation/drug effects , Clone Cells/immunology , Dimethyl Sulfoxide/pharmacology , Humans , Leukemia/immunology , Molecular Weight , Phenotype , Phorbol Esters/pharmacology , T-Lymphocytes/immunologyABSTRACT
Methods are described for analysing chemical and biochemical properties of membrane antigens against which monoclonal antibodies are available. The methods are based on gentle manipulation of whole viable cells and quantitative flow cytometric fluorescence analysis of the effect of such treatment on monoclonal antibody binding. Proteolytic enzymes, glycosidases, inhibitors of biosynthesis and various mild chemical treatments have been used to derive information on the chemical nature of individual membrane antigens, their insertion in the membrane, and their turnover. The nature of the particular epitope detected by a monoclonal antibody may be probed in a similar way.
Subject(s)
Antibodies, Monoclonal , Antigens, Surface/analysis , Antigen-Antibody Complex , B-Lymphocytes/immunology , Carbohydrates , Cell Line , Flow Cytometry/methods , Fluorescent Antibody Technique , Glycoside Hydrolases , Humans , Lectins , T-Lymphocytes/immunology , Tunicamycin/pharmacologyABSTRACT
The monoclonal antibody FMC7 delineates a subpopulation of B lymphocytes in normal blood. Expression of the antigen recognized by FMC7 appears to be maturation-linked, and it serves to distinguish different types of B cell leukemia. The data presented here indicate that the antigen is a protein that is integrated in the cell membrane and that is able to interact with the cytoskeleton. The antigen is rapidly synthesized and turned over, is not cell cycle-dependent, and is relatively resistant to changes induced by culture in the presence of a phorbol ester.
