Determination of cell membrane bound IgE in allergic patients and healthy controls. A new technology.
Cell membrane bound IgE was determined in 44 allergic patients and 34 healthy controls with a radiobinding technique using I-125 labeled anti-IgE as a marker. The technique possesses an intraassay variability of 10% and an interassay variability of 20%. Owing to the possibility that anti-IgE may bind to the cell membrane via the Fc receptor, IgE was detached from the membrane by gradually reducing pH to 4 and quantitating bound anti-IgE. This procedure led to an 83 +/- 14.23% drop in I-125 anti-IgE uptake. However, other cell markers tested (OKT-3, OKT-4, IgG) as well as cell viability remained unchanged, thus demonstrating the high degree of specific labeled anti-IgE uptake by IgE molecules on the cell membrane. The results presented to date support the usefulness of the technique described. Hence, bound IgE was determined in allergic subjects and controls, and correlated to the free serum levels of IgE. The results show that greater quantities of IgE are found on the cell membranes of allergic patients in comparison to the control population. In 81% of the former, uptake surpassed 3% of the total amount of isotope added, whereas 85% of the control subjects showed less than 3% uptake. No statistically significant correlation was obtained between serum IgE (UI/ml) and bound IgE levels in allergic subjects. Double immunofluorescence assays demonstrated the presence of cells with surface-bound IgE (s IgE +) which also expressed HLA class II (DR) molecules. Protein synthesis blocking studies showed IgE on the cell membrane to have a predominantly carrier role.
de Urquía
M
M
Department of Immunology, Reina Sofía Medical Center, Córdoba, Spain.
Monserrat
J
J
Santamaría
M
M
Grerra
F
F
Cutando
A
A
Peña
J
J
D000888:Antibodies, Anti-Idiotypic; D002462:Cell Membrane / Q000032:analysis*; D003609:Dactinomycin; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D007073:Immunoglobulin E / Q000032:analysis* / Q000276:immunology; D011237:Predictive Value of Tests; D011863:Radioimmunoassay; D011947:Receptors, Antigen, B-Cell / Q000032:analysis*
D000888:Antibodies, Anti-Idiotypic; D006684:HLA-DR Antigens; D011947:Receptors, Antigen, B-Cell; C026408:anti-IgE antibodies; D003609:Dactinomycin; D007073:Immunoglobulin E