Co-stimulation of human peripheral blood mononuclear cells with IL-2 and anti-CD3 monoclonal antibodies induces phosphorylation of CREB

Deborah J. Guyot, Garret C. Newbound, Michael Dale Lairmore

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Phosphorylation of the cAMP-response element binding protein CREB within 1 h of CD2 but not CD3 cross-linking of human PBMC was recently demonstrated. The absence of P-CREB following CD3 cross-linking was unexpected, as other laboratories reported increased phosphorylation of CREB following CD3 cross- linking of the Jurkat lymphocyte cell line. Due to Jurkat T-cells being IL- 2-independent, it was postulated that IL-2 might provide a necessary co- stimulus for phosphorylation of CREB in primary lymphocytes. Therefore, P- CREB was evaluated following co-stimulation of human PBMC through the IL-2 and CD2 or CD3 receptors. IL-2 did not further augment phosphorylation of CREB following CD2 cross-linking. However, while neither IL-2 nor CD3 cross- linking alone induced P-CREB, a 4.5-fold increase in phosphorylation of CREB within 1 h of IL-2/CD3 co-stimulation was observed. Phosphorylation was not associated with the induction of cAMP, and inhibition of PKA signaling had no effect on P-CREB. Consistent with signal transduction through p56(lck) or p59(fyn), inhibition of PTK signaling reduced phosphorylation 50%. Interestingly, inhibiting PKC signaling with calphostin C further increased P-CREB levels 3-fold over that observed in IL-2/CD3 co-stimulated cells not pretreated with a PKC inhibitor. In contrast to previous studies performed in the absence of exogenous IL-2, no increase in binding of CREB to a 32P- labeled oligonucleotide probe was observed by electrophoretic mobility shift assay. These data suggest that the IL-2 and CD3 signaling pathways provide a necessary and co-operative stimulus promoting phosphorylation of CREB following receptor cross-linking.

Original languageEnglish (US)
Pages (from-to)45-52
Number of pages8
JournalImmunology Letters
Volume61
Issue number1
DOIs
StatePublished - Mar 1998
Externally publishedYes

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Keywords

  • cAMP-response
  • CD2
  • CD3
  • IL-2
  • Protein kinases
  • T iymphocytes

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

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