Long-term inositol phosphate release, but not tyrosine kinase activity, correlates with IL-2 secretion and NF-AT induction in anti-CD3-activated peripheral human T lymphocytes.
The cascade of events within the first few minutes of T cell stimulation has been well characterized. Although many second messengers have been shown to be necessary and sufficient for T cell activation in a number of model systems, the rate-limiting step in peripheral T cells has not been demonstrated. To model effective versus ineffective CD3-mediated stimulation in peripheral T cells, we used two anti-CD3 mAbs that differ in their ability to stimulate purified T cells: OKT3, which causes early second messenger generation but is unable to activate T cells without a second signal, and 64.1, which stimulates T cell proliferation on its own. We found that tyrosine kinase activity was similar for both mAbs over a period of hours. However, the inositol phosphate response was stronger for 64.1 than for OKT3. To tie these events to gene activation, we measured NF-kappa B and NF-AT activity in the nucleus after anti-CD3 stimulation. Both stimuli induced the appearance of the NF-kappa B components (c-Rel, p65 (RelA), and p50 (NF-kappa B1)) and NF-kappa B DNA binding activity in the nucleus. However, only 64.1 induced NF-AT in the nucleus, correlating with its ability to activate T cells. Thus, NF-AT induction and IL-2 secretion were correlated with the levels of inositol phosphate release but not with gross levels of tyrosine kinase activity induced late following the response. On the other hand, NF-kappa B induction and IL-2 receptor expression occurred even with the smaller second messenger response generated by OKT3.
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, Texas 77030.
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Bryan
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Totten
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Van
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Rich
D000911:Antibodies, Monoclonal; D001483:Base Sequence; D017252:CD3 Complex / Q000276:immunology / Q000502:physiology; D002118:Calcium / Q000502:physiology; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D006801:Humans; D007295:Inositol Phosphates / Q000502:physiology*; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000502:physiology; D008969:Molecular Sequence Data; D016853:Muromonab-CD3 / Q000276:immunology / Q000502:physiology; D016328:NF-kappa B / Q000096:biosynthesis; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D015290:Second Messenger Systems / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000502:physiology*; D014157:Transcription Factors / Q000096:biosynthesis
D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D004268:DNA-Binding Proteins; D007295:Inositol Phosphates; D007376:Interleukin-2; D016853:Muromonab-CD3; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases; D002118:Calcium