Increased sensitivity of rosetting assay for Fc receptors obtained by using non-hemagglutinating monoclonal antibodies.
The sensitivity of the conventional EA (Fc) rosetting assay for detecting Fc receptors could be significantly increased by coating sheep erythrocytes (SRBC) with high concentrations of a preparation of homogeneous monoclonal IgG2b anti-SRBC antibodies. This was made possible by virtue of the fact that the monoclonal antibody preparation used was completely incapable of directly hemagglutinating SRBC, although it possessed a high titer as assessed by direct hemolysis or direct hemagglutination. The monoclonal IgG2b- coated SRBC indicator cells were compared to SRBC coated with subhemagglutinating amounts of the IgG fraction of a hemagglutinating rabbit anti-SRBC antiserum: at high coupling concentrations, the monoclonal antibody-coupled SRBC gave consistently higher percentages of Fc rosettes, a large proportion of which were large and multi-layered, when various lymphoid cell populations and a variety of Fc receptor-positive cultured tumor cell line populations were tested. The increased sensitivity of the Fc rosette attained by this method may depend on the nature of the monoclonal anti-SRBC reagent used. Thus, indicator cells prepared by incubation with high concentrations of IgG1 subclass-specific non-hemagglutinating monoclonal anti-SRBC antibodies always gave significantly lower percentages of Fc rosettes than conventionally prepared indicator cells.
D000818:Animals; D000906:Antibodies; D000917:Antibody Formation; D002999:Clone Cells / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D006041:Goats; D006386:Hemagglutination Tests; D007939:Leukemia L1210 / Q000276:immunology; D051379:Mice; D008811:Mice, Inbred DBA; D009374:Neoplasms, Experimental / Q000276:immunology*; D011817:Rabbits; D011961:Receptors, Fc; D012397:Rosette Formation; D012756:Sheep
D000906:Antibodies; D011961:Receptors, Fc