The present results indicate that B cells isolated from chronic lymphocytic leukemia (B-CLL) from 11 of 14 patients are capable of specifically producing IgE upon costimulation with IL-4 and hydrocortisone (HC). IgE is detected by intracytoplasmic fluorescence staining and by RIA. Clinical, hematological, and immunological parameters (including Rai stage, WBC, Lc, sIg kappa/lambda, CD5, and CD2...

The Fc region of immunoglobulin E (IgE) comprising the C epsilon 3 and C epsilon 4 domains (residues 329-547) is sufficient for binding to the high-affinity IgE Fc receptor (Fc epsilon RI alpha). Three potential N-linked glycosylation sites are present within the C epsilon 3 domain. To determine the effect of the glycosylation sites on IgE Fc synthesis and on Fc epsilon RI alpha binding, site-d...

Interleukin 4 (IL-4)-induced IgE production coincides with the appearance of the 2.2-kb productive epsilon-mRNA, but is preceded by synthesis of a 1.7-kb epsilon-RNA. Analysis of cDNA copies of the 5' end of this RNA indicated that the 1.7-kb epsilon-RNA is a germline epsilon immunoglobulin heavy chain transcript with an exon mapping 5' to the switch region. Transcription through switch regions...

To elucidate the role of retinoic acid (RA) in anti-CD40 + interleukin-4 (IL-4)-mediated B-cell activation, the effect of 10(-12) to 10(-6) mol/L RA was studied in anti-CD40 (1 microgram/mL) + IL-4 (5 ng/mL)-mediated proliferation and Ig synthesis by human peripheral blood mononuclear cells (PBMC) and B cells in healthy donors. Anti-CD40 + IL-4-mediated proliferation of PBMC and B cells was inh...

BACKGROUND Treating asthmatics with the humanized IgE-scavenging antibody, omalizumab (rhuMAb-E25, Xolair, reduces airways inflammation and asthma symptoms. Previously, omalizumab was shown to cause a dramatic and reversible loss of cell surface high-affinity IgE receptors, FcepsilonRI, from the peripheral blood basophils of asthmatics. The consequences of receptor loss for the FcepsilonRI-medi...

The induction of immunoglobulin E (IgE) switching in B cells requires at least two signals. The first is given by either of the soluble lymphokines interleukin 4 (IL-4) or IL-13, whereas the second is contact dependent. It has been widely reported that a second signal can be provided by the CD40 ligand (CD40L) expressed on the surface of T cells, mast cells, and basophils. A defect in the CD40L...

Immunoglobulin (Ig) E production by B cells requires two primary signals provided by T cells, interleukin (IL)-4 or IL-13 and CD40 ligand (CD40L). In addition, costimulatory signals, such as CD23-CD21 interaction, contribute further ensuring a selective control over this production. Recently, CD28, expressed on T cells, has been reported to be involved in this process. The CD28 ligands, CD80 (B...

The antibody IgE plays a central role in allergic disease mechanisms. Its effector functions are controlled through interactions between the Fc region and two principal cell surface receptors FcεRI and CD23. The interaction with FcεRI is primarily responsible for allergic sensitization and the inflammatory response, while IgE binding to CD23 is involved in the regulation of IgE synthesis and al...

Background: IgE is closely related to the development of allergies. However, the poor relationship between the specific IgE level and the severity of allergic diseases suggests the possibility of functionally different IgE isoforms. With this in mind, rat basophilic leukemia (RBL)-2H3 activation was analyzed with each type of rat IgE for two parameters, exocytosis and IL-4 mRNA production. RBL-...