Fc receptors for IgG1 and IgG3 on human mononuclear cells--an evaluation with known levels of erythrocyte-bound IgG.
The Fc receptors on mononuclear cells were investigated by a rosette technique in which human erythrocytes were sensitized with a known number of molecules of anti-Rh antibodies (IgG1 or IgG3). The number of IgG molecules was quantitated by a radiometric antiglobulin test. The present quantitative evaluation reveals that (1) there is a logarithmic relationship between the proportion of rosettes and the amount of erythrocyte-bound immunoglobulin for both types of mononuclear cells, and for both subclasses; (2) similar percentage of rosettes can be obtained with fewer IgG3 than IgG1 molecules (about 1:4); (3) for a given number of erythrocyte-bound immunoglobulins a higher percentage of rosettes is observed with monocytes than with lymphocytes (ratios of about 3:1 for IgG1 and 5:1 for IgG3); (4) the minimum number of IgG3 molecules for adherence is 180-460 for monocytes, 520-1,300 for lymphocytes, whilst for IgG1 the numbers are 1,180-4,300 for monocytes and 3,400-14,200 for lymphocytes; (5) the minimum levels of sensitization by alloantibodies for adherence should be detectable by the antiglobulin test.
D001323:Autoantibodies / Q000032:analysis; D004912:Erythrocytes / Q000276:immunology; D005069:Evaluation Studies as Topic; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007518:Isoantibodies / Q000032:analysis / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology* / Q000648:ultrastructure; D009000:Monocytes / Q000276:immunology* / Q000648:ultrastructure; D011247:Pregnancy; D011874:Radiometry / Q000379:methods; D011961:Receptors, Fc / Q000032:analysis / Q000276:immunology*; D012397:Rosette Formation
D001323:Autoantibodies; D007518:Isoantibodies; C033242:RH-antibodies; D011961:Receptors, Fc