Antigen receptor proximal signaling in splenic B-2 cell subsets

X. Li, F. Martin, Alyce M. Oliver, J. F. Kearney, R. H. Carter

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Splenic marginal zone (MZ) and follicular mantle (FO) B cells differ in their responses to stimuli in vitro and in vivo. We have previously shown that MZ cells exhibit greater calcium responses after ligation of membrane IgM (mIgM). We have now investigated the molecular mechanism underlying the difference in calcium responses following ligation of mIgM and studied the response to total B cell receptor ligation in these two subsets. We compared key cellular proteins involved in calcium signaling in MZ and FO cells. Tyrosine phosphorylation and activity of phospholipase C-γ2 and Syk protein tyrosine kinase were significantly higher in MZ cells than in FO cells after mIgM engagement, providing a likely explanation for our previous findings. Tyrosine phosphorylation of CD22 and expression of Src homology 2-containing inositol phosphatase and Src homology 2-containing protein tyrosine phosphatase-1 were also higher in the MZ cells. Expression and tyrosine phosphorylation of Btk, BLNK, Vav, or phosphatidylinositol 3-kinase were equivalent. In contrast, stimulation with anti-κ induced equivalent increases in calcium and activation of Syk in the two subsets. These signals were also equivalent in cells from IgM transgenic, JH knockout mice, which have equivalent levels of IgM in both subsets. With total spleen B cells, Btk was maximally phosphorylated at a lower concentration of anti-κ than Syk. Thus, calcium signaling in the subsets of mature B cells reflects the amount of Ig ligated more than the isotype or the subset and this correlates with the relative tyrosine phosphorylation of Syk.

Original languageEnglish (US)
Pages (from-to)3122-3129
Number of pages8
JournalJournal of Immunology
Volume166
Issue number5
DOIs
StatePublished - Mar 1 2001

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B-Lymphocyte Subsets
Antigen Receptors
Immunoglobulin M
Tyrosine
Phosphorylation
Ligation
B-Lymphocytes
Calcium Signaling
Calcium
Phosphatidylinositol 3-Kinase
Protein Phosphatase 1
Protein Tyrosine Phosphatases
Membranes
Type C Phospholipases
Knockout Mice
Protein-Tyrosine Kinases
Protein Kinases
Spleen
Cell Membrane
Proteins

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

Cite this

Antigen receptor proximal signaling in splenic B-2 cell subsets. / Li, X.; Martin, F.; Oliver, Alyce M.; Kearney, J. F.; Carter, R. H.

In: Journal of Immunology, Vol. 166, No. 5, 01.03.2001, p. 3122-3129.

Research output: Contribution to journalArticle

Li, X. ; Martin, F. ; Oliver, Alyce M. ; Kearney, J. F. ; Carter, R. H. / Antigen receptor proximal signaling in splenic B-2 cell subsets. In: Journal of Immunology. 2001 ; Vol. 166, No. 5. pp. 3122-3129.
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