CD9 is a unique marker for marginal zone B cells, B1 cells, and plasma cells in mice.

The CD9 tetraspanin is not required for the development of peripheral B cells or for humoral immunity.

The CD9 tetraspanin is known to be expressed at high levels on marginal zone (MZ) B cells, B-1 B cells, and plasma cells, and its expression is believed to be dependent on signals derived via Btk. In CD9 null mice, however, the development and survival of MZ B cells, B-1 B cells, and plasma cells all appear to be unaffected, and humoral immune responses to T-dependent and T-independent Ags are ...

CD38 MOLECULE-A MULTILINEAGE GLYCOPROTEIN AND ITS UNIQUE EXPRESSION ON PLASMA CELLS

A hybridoma clone designated 6G5 has been selected by fusion of mouse myeloma cell line Ag. 8653 with spleen cells from mice immunized with human peripheral blood mononuclear cells (PBMC). The antibody produced by this clone was found to be strongly reactive with four human B-cell lines in the conventional immunological assays. Despite the fact that expression of most B cell-associated mar...

Plasma Cells in Mice CD 9 Is a Unique Marker for Marginal Zone B

The calcineurin phosphatase complex modulates immunogenic B cell responses.

A series of signal-directed transitions regulates the development of distinct populations of self-tolerant B cells and ultimately the production of antibody-producing plasma cells. We studied the role of calcineurin/NFAT signaling in B cells by deleting the regulatory b1 subunit of calcineurin specifically in B cells. Follicular (FO) and marginal zone (MZ) B cells develop normally in these mice...

Fc receptor homolog 3 is a novel immunoregulatory marker of marginal zone and B1 B cells.

Two members of the recently identified FcR homolog (FcRH) family in mice demonstrate preferential B cell expression. One of these, FcRH3, encodes a type I transmembrane protein with five extracellular Ig domains and a cytoplasmic tail with a consensus ITIM and a noncanonical ITAM. Analysis of full-length cDNAs from five different mouse strains defines two FcRH3 alleles. A panel of FcRH3-specifi...