Abstract
Background
The mushroom Phellinus linteus (PL) has been shown to have the anti-tumor and immunostimulatory effects. We hypothesized that the hot water extract of PL (WEPL) exerts its significant immunostimulatory effect by inducing production of the Th1-derived cytokine interferon-γ (IFN-γ) by T lymphocytes.
Methods
T lymphocytes were isolated from the mice fed with 200 mg/kg of WEPL once a day for 4 weeks, and then stimulated with the mitogen concanavaline A (Con A). IFN-γ gene and intracellular protein expressions were analyzed by RT-PCR and flow cytometry, respectively. The production of IFN-γ was measured by enzyme-linked immunosorbent assay.
Results
WEPL significantly enhanced the transcription of IFN-γ mRNA. The effect of WEPL on IFN-γ expression was further supported by a concomitant increase in the number of cells with intracellular IFN-γ protein as well as the secretion of IFN-γ. However, WEPL did not modulate either gene expression or protein secretion of interleukin-4, a Th2-associated cytokine, by Con A-stimulated T lymphocytes.