Immunoglobulin-mediated signal transduction in B cells from CD45-deficient mice

Tania Benatar, Rita Carsetti, Caren Furlonger, Nilupa Kamalia, Tak Mak, Christopher J. Paige

Research output: Contribution to journalArticlepeer-review

Abstract

CD45 expression is essential for immunoglobulin (Ig)-mediated B cell activation. Treatments with either anti-Ig or anti-CD45 suggest that CD45 may facilitate early signaling events such as calcium mobilization, and phosphoinositide hydrolysis as well as later events leading to transcription of genes such as c-myc. To examine the role of CD45 more extensively, CD45- deficient mice were generated by disruption of exon 6. Although normal numbers of B cells were found in peripheral lymphoid tissues, CD45-deficient cells failed to proliferate upon IgM cross-linking. In the present study, we demonstrate that the fraction of high buoyant density B cells is reduced while low buoyant density cells are increased. Moreover, there is a significant decline in the number of splenic B cells of the mature IgD(hi), IgM(lo) phenotype. Although both the basal and anti-Ig-induced levels of phosphorylation of Ig-α and phospholipase Cγ2 are indistinguishable from that observed in CD45+ control B cells, a major distinction was found in Ca2+ mobilization. While anti-Ig-induced mobilization of intracellular Ca2+ stores was normal, influx from extracellular sources was abrogated. This finding reveals a novel pathway of regulating B cell responses mediated by CD45.

Original languageEnglish
Pages (from-to)329-334
Number of pages6
JournalJournal of Experimental Medicine
Volume183
Issue number1
DOIs
Publication statusPublished - Jan 1 1996

ASJC Scopus subject areas

  • Immunology

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