title: Fractionation of cells on a discontinuous Ficoll gradient. Study of subpopulations of human T cells using anti-T-cell antibodies from patients with systemic lupus erythematosus.
abstract: Patients with active systemic lupus erythematosus (SLE) had a decrease in a subpopulation of cells (fraction D) when peripheral blood lymphocytes were separated on a discontinuous Ficoll gradient. Preincubation of SLE cells at 37 degrees C for 30 min led to a marked decrease in this fraction, composed primarily of thymus-derived (T) cells. Supernates of such preincubations were found to cause a reduction in fraction D cells from normal humans. The active factor in the supernate was found to be an IgG antibody. Similarly, serum from patients with active SLE produced a reduction in fraction D cells from normal donors. This activity was also found in the IgG fraction, and could be absorbed with a pure T-cell population. Depletion of macrophages and complement did not reduce the SLE anti-T-cell antibody-mediated loss of cells from fraction D; however, heat-aggregated human gamma globulin led to impairment of the reaction. These findings suggest that antibody-dependent direct lymphocyte-mediated cytotoxicity may play a role in T-cell lymphopenia of SLE. It was further noted that the SLE anti-T-cell antibodies, in contrast to rabbit antihuman thymocyte serum, recognized fraction D cells but not fraction E cells from normals. Since both fractions are largely T cells, it appeared that the SLE serum was directed against cell-membrane antigenic determinants present on fraction D T cells, which were absent or reduced in quantity on fraction E T cells. Thus, evidence was presented indicating the presence of at least two subpopulations of cells in man. This was supported by differential absorption of the anti-T-cell sera with fractions D and E.
mesh_terms: D000906:Antibodies; D002458:Cell Fractionation; D003165:Complement System Proteins; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D005362:Ficoll; D006801:Humans; D007104:Immune Adherence Reaction; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007958:Leukocyte Count; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D008297:Male; D010084:Oxidation-Reduction; D013601:T-Lymphocytes / Q000276:immunology*; D005719:gamma-Globulins
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D005719:gamma-Globulins; D005362:Ficoll; D003165:Complement System Proteins