Quantitative Rather than Qualitative Differences between Monocytes with Respect to IgE Fc Receptor Expression as Studied by Flow Cytofluorometry

Abstract

In this study we have used aggregated human IgE, conjugated with fluoroisothiocyanate, as a ligand in flow cytofluorometry to detect the low-affinity Fc receptor for IgE on human leukocytes. The percentage of IgE-binding monocytes increased up to 44%, in a dose-related manner, as the concentration of aggregated IgE in the fluid phase increased to the highest concentration (300 μg/ml) used in this study. No such dose-related increase was shown for granulocytes (1.8% IgE-binding cells) or lymphocytes (2.1 % IgE-binding cells). The IgE-binding was inhibited by IgE but not by IgG, whereas the opposite effect was obtained for IgG binding. We could not verify a distinct IgE-binding subpopulation of monocytes in peripheral blood. The results rather indicate that most monocytes bind IgE to a variable degree depending on the concentration of the ligand in the fluid phase.

Contrasting functions of IgG and IgE antimalarial antibodies in uncomplicated and severe Plasmodium falciparum malaria.

“…Total IgE and IgG, and antimalarial IgE and IgG antibodies were determined by ELISA as described. 2,14 Sera containing antigenbinding IgE or IgG above the background of Swedish controls (IgE 0.40 ng/ml, IgG 15.49 g/ml; means ϩ2 SD) who had not encountered malaria were defined as antibody positive. All results are given as geometric means.…”

Antenatal Betamethasone Changes Cord Blood Monocyte Responses to Endotoxin in Preterm Lambs

“…Trypan blue (1.25 mg/mL) was added to one aliquot to measure ingested bacteria only. Trypan blue quenches fluorescence of FITC-labeled E. coli that are surface bound but not ingested (17).…”

IgE elevation and IgE anti-malarial antibodies in Plasmodium falciparum malaria; association of high IgE levels with cerebral malaria

“…Denmark). After washing of the plates, the test sera, diluted 1:1000 for total IgE or hlO*" for total IgG, were added to the wells and incubated at 37 C for I h. The total IgE bound to the plates was then assayed with biotinylated e-chain specific rabbit anti-IgE antibodies, followed by alkaline phosphatase (ALP)-conjugated Streptavidine (Mabtech, Stockholm, Sweden), IgG was assayed with ALP-conjugated rabbit anti-human IgG antibodies (Fc-7-specific; Dakopatts), Immunoglobulin concentrations were calculated from standard curves obtained by incubating the coated plates with five dilutions of either IgE (purified myeloma protein IgE) [24]. or highly purified IgG (Jaekson Immuno Research Labs, West Grove, PA).…”