<i>Plasmodium falciparum</i>–specific IgM B cells dominate in children, expand with malaria, and produce functional IgM

Late Immature B Cells (IgM

Immunoglobulin IgG, IgM, IgA, and IgE Levels in Children with Chronic Sinusitis

Background and purpose: Sinusitis is a common disease in children that can lead to acute and chronic problems and sometimes severe complications. There is lack of evidence on underlying causes of chronic sinusitis in children in Iran, so, this study aimed to investigate the prevalence of humoral immune deficiency in patients with chronic sinusitis. Materials and methods: This cross-sectional s...

A functional BCR in human IgA and IgM plasma cells.

Plasma cells (PCs) are terminally differentiated cells of the B-cell lineage that secrete antibodies at a high rate and are thought to lack the expression of the B-cell receptor (BCR). Here, we report that human IgA and IgM, unlike IgG, PCs express a membrane functional BCR associated with the Igα/Igβ heterodimer. BCR cross-linking on IgA and IgM PCs led to Ca(2+) mobilization and extracellular...

Human leukemic B cell activation: functional consequence of membrane IgM interaction with anti-IgM ligand is an alterable cell characteristic.

A functional study of several human malignant B cell populations has indicated that occasional leukemic clones are extraordinarily sensitive to signal transduction through membrane IgM. One isolated hairy cell leukemia (HCL) with low background DNA synthesis was stimulated to significant levels of DNA synthesis when cultured with high (100 micrograms/mL) concentrations of soluble anti-IgM ligan...

Functional diversity of natural IgM.

This paper proposes a method for the quantitative characterization of repertoire diversity of an unknown mixture of antibodies on the basis of its reactivity profile in the quantitative immunoblot (QIB). The QIB is calibrated by measuring the reactivity profiles of supernatants of known 'diversity' (i.e. known numbers of B cell clones). We define a quantitative 'index of variability' (IV) which...