The enumeration of mouse IgE-secreting cells using plaque-forming cell assays

With the aid of a specific rabbit antibody preparation to purified monoclonal murine IgE, two plaque-forming cell (PFC) assays have been developed for the detection and enumeration of mouse IgE-secreting cells. The first assay, utilizing protein A-coated sheep red cells (protein A-SRC), detected antibody-secreting cells on the basis of the class of the secreted Ig irrespective of antigen specificity. With this assay, 30% of the class of the viable cells of two distinct IgE-secreting hybridoma cell lines were scored as PFC. Under these conditions, plaques were not obtained with IgG1 or IgG2a-secreting hybridoma cells. The second PFC assay, which utilized SRC coated with ovalbumin (OA-SRC), enumerated cells secreting anti-OA IgE antibodies. Similar kinetic patterns were observed for the cellular (IgE PFC/spleen) and humoral (IgE serum levels) responses of (C57BL/6 x DBA/2)F1 mice following immunization with 10 micrograms of OA adsorbed to 1 mg of A1(OH)3. Thus, it is concluded that the reverse plaque assay detecting all IgE-secreting cells, as well as the antigen-specific IgE PFC assay, can be used for the quantitation of IgE responses at the cellular level.