ABSTRACT
The central event in the generation of immune responses is the activation and clonal expansion of T cells. Interaction of T cells with antigens initiates a cascade of biochemical events and gene expression that induces the resting T cells to activate and proliferate [1]. Activation of nuclear factor of activated T cells (NF-AT) and a series of genes such as interleukin-2 (IL-2) and interferon-γ (IFN-γ) are pivotal in the growth of T lymphocytes induced by antigens [2,3]. Thus, growth modulators or other external events affecting T cell proliferation are likely to act by controlling the expression or function of the products of these genes [4]. The immune responses to invasive organisms, if inappropriately intense or prolonged, may paradoxically aggravate the injury or even cause death. The use of immunomodulatory medications must therefore be discreet. Regulation of
T lymphocyte activation and proliferation and cytokine production is one of the action mechanisms [5,6].
