The FcμR receptor for the crystallizable fragment (Fc) of immunoglobulin M (IgM) can function as a cell-surface receptor for secreted IgM on a variety of cell types. We found here that FcμR was also expressed in the trans-Golgi network of developing B cells, where it constrained transport of the IgM-isotype BCR (IgM-BCR) but not of the IgD-isotype BCR (IgD-BCR). In the absence of FcμR, the surface expression of IgM-BCR was increased, which resulted in enhanced tonic BCR signaling. B-cell-specific deficiency in FcμR enhanced the spontaneous differentiation of B-1 cells, which resulted in increased serum concentrations of natural IgM and dysregulated homeostasis of B-2 cells; this caused the spontaneous formation of germinal centers, increased titers of serum autoantibodies and excessive accumulation of B cells. Thus, FcμR serves as a critical regulator of B cell biology by constraining the transport and cell-surface expression of IgM-BCR.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310993 | PMC |
http://dx.doi.org/10.1038/ni.3677 | DOI Listing |
J Ethnopharmacol
January 2025
The College of Life Sciences, Northwest University, Xi'an, Shaanxi, 710069, PR China. Electronic address:
Ethnopharmacological Relevance: Codonopsis Pilosula (CP), as a well-known traditional Chinese medicine (TCM) with medicinal and edible herb, is one of the most representative tonic Chinese herbal medicine. It has been widely used for regulating immune function with hardly any adverse effects in clinical practice.
Aim Of The Study: This study aimed to elucidate the immunomodulatory effect and to explore probable mechanism of Codonopsis Pilosula Extract (CPE) in septic rats.
J Biol Chem
September 2024
Department of Immunology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan; Department of Pathology, Nihon University School of Dentistry, Tokyo, Japan. Electronic address:
CD22 (also known as Siglec-2) is an inhibitory receptor expressed in B cells. CD22 specifically recognizes α2,6 sialic acid and interacts with α2,6 sialylated membrane proteins expressed on the same cell (cis-ligands) and those derived from outside of the cell (trans-ligands). Previously, CD22 cis-ligands were shown to regulate the activity of CD22, thereby regulating both BCR ligation-induced signaling and low-level "tonic" signaling in the absence of BCR ligation that regulates the survival and differentiation of B cells.
View Article and Find Full Text PDFBr J Haematol
June 2024
Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA.
Multiagent chemoimmunotherapy remains the standard of care treatment for Burkitt lymphoma leading to a cure in the majority of cases. However, frontline treatment regimens are associated with a significant risk of treatment related toxicity especially in elderly and immunocompromised patients. Additionally, prognosis remains dismal in refractory/relapsed Burkitt lymphoma.
View Article and Find Full Text PDFEur J Immunol
March 2024
Institute for Cellular and Molecular Immunology, University Medical Center Goettingen, Goettingen, Germany.
The structure and dynamics of F-actin networks in the cortical area of B cells control the signal efficiency of B-cell antigen receptors (BCRs). Although antigen-induced signaling has been studied extensively, the role of cortical F-actin in antigen-independent tonic BCR signaling is less well understood. Because these signals are essential for the survival of B cells and are consequently exploited by several B-cell lymphomas, we assessed how the cortical F-actin structure influences tonic BCR signal transduction.
View Article and Find Full Text PDFInt J Mol Sci
December 2023
BIOCEV, First Faculty of Medicine, Charles University, Prumyslova 595, 252 50 Vestec, Czech Republic.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!