Luminescent immunoassay (LIA) for progesterone in a heterogeneous system.

An immunoassay procedure for determination of progesterone in human plasma is described which utilizes chemiluminescence as the endpoint. The assay utilized progesterone-11-hemisuccinate-aminobutyl-ethyl-isoluminol (P-11-HS-ABEI) as the chemiluminescent marker conjugate and dextran coated charcoal for the separation of bound and free fractions of the ligand. An assay procedure for progesterone was established and validated in terms of sensitivity and precision, and assay results were compared with radioimmunoassay, using tritiated progesterone as the tracer. The two methods agreed well (n=35, r=0.96). The most important advantage of this assay is the elimination of problems inherent in the use of radioactive materials.

Comparison of superoxide generation and luminol-dependent chemiluminescence with eosinophils and neutrophils from normal individuals.

Although eosinophilia is found in many allergic and hypersensitivity diseases, the function of the eosinophil is not clearly established. To evaluate and characterize this function, anticoagulated blood from normal subjects was separated into purified populations of both eosinophils and neutrophils by a modified method for Percoll gradients. With this separation procedure, highly purified populations of eosinophils (95.0% +/- 2.1%) and neutrophils (97.2% +/- 0.4%) were obtained. Functional response of these two isolated granulocyte cell types was measured by luminol-dependent chemiluminescence (CL) and superoxide generation to opsonized zymosan and phorbol 12-myristate 13-acetate (PMA). Both the eosinophil and neutrophil peak CL response and superoxide generation to zymosan (1 mg), in the presence of autologous serum (10%), were identical. In contrast, when PMA (10(-4) to 10(0) micrograms/ml) was the stimulant, eosinophil CL was at least twofold greater than the neutrophil light emission (1,595,741 +/- 122,435 cpm/5 X 10(5) cells vs. 765,448 +/- 24,171 cpm/5 X 10(5) cells; n = 6). This same differential in responsiveness was seen in superoxide generation. Thus, under certain conditions the eosinophil's respiratory burst may be greater than that of the neutrophil, and this differential in metabolic activity may contribute directly to the eosinophil's inflammatory potential.