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Rapid burst of H2O2 by plant growth regulators increases intracellular Ca2+ amounts and modulates CD4(+) T cell activation

Ahmed, Asma and Mukherjee, Sambuddho and Deobagkar, Mukta and Naik, Tanushree and Nandi, Dipankar (2010) Rapid burst of H2O2 by plant growth regulators increases intracellular Ca2+ amounts and modulates CD4(+) T cell activation. In: International Immunopharmacology, 10 (11). pp. 1397-1405.

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Official URL: http://dx.doi.org/10.1016/j.intimp.2010.08.005

Abstract

The identification of small molecules that affect T cell activation is an important area of research. Three molecules that regulate plant growth and differentiation, but not their structurally similar analogs, were identified to enhance primary mouse CD4(+) T cell activation in conjunction with soluble anti-CD3 stimulation: Indoleacetic acid (natural plant auxin), 1-Napthaleneacetic acid (synthetic plant auxin) and 2,4-Dichlorophenoxyacetic acid (synthetic plant auxin and herbicide). These effects are distinct in comparison to Curcumin, the well known phenolic immunomodulator, which lowers T cell activation. An investigation into the mechanisms of action of the three plant growth regulators revealed a rapid induction of reactive oxygen species (ROS), mainly comprising H2O2 . In addition, these three molecules synergize with soluble anti-CD3 signaling to enhance intracellular Ca2+ concentrations Ca2+](i), leading to greater T cell activation, e.g. induction of CD25 and IL-2. Enhanced production of TNF alpha and IFN gamma by CD4+ T cells is also observed upon plant growth regulator treatment with soluble anti-CD3. Interestingly, maximal IL-2 production and CD4(+) T cell cycle progression are observed upon activation with soluble anti-CD3 and phorbol 12-myristate 13-acetate (PMA), a phorbol ester. Additionally, stimulation with PMA and Ionomcyin (a Ca2+ ionophore), which activates T cells by circumventing the TCR, and plant growth regulators also demonstrated the role of the strength of signal (SOS): T cell cycle progression is enhanced with gentle activation conditions but decreased with strong activation conditions. This study demonstrates the direct effects of three plant growth regulators on CD4(+) T cell activation and cycling. (C) 2010 Elsevier B.V. All rights reserved.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Auxin; Intracellular Ca2+; IL-2; Reactive oxygen species; T cell activation.
Department/Centre: Division of Biological Sciences > Biochemistry
Date Deposited: 21 Dec 2010 11:14
Last Modified: 21 Dec 2010 11:14
URI: http://eprints.iisc.ernet.in/id/eprint/34572

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