Thymoquinone, the active ingredient of Nigella sativa seeds, enhances survival and activity of antigen-specific CD8-positive T cells in vitro.

Recent preclinical and clinical studies provide evidence that adoptive transfer of in vitro activated T cells can results in significant antitumour responses in vivo upon acquisition of certain survival and homing properties during in vitro activation. Based on recent studies showing in vivo antioxidant effects of thymoquinone (TQ), the active ingredient of Nigella sativa seeds, this study aims to determine whether or not TQ can increase survival and sustain the expression of the homing receptor CD62L in antigen-specific T cells in vitro. The results showed that stimulation of OT-1 (transgenic CD+) T cells with OVA antigen resulted in activation, as shown by a decrease in the surface expression of CD62L which coincided with significant apoptosis measured three and five days after antigen stimulation. Addition of low concentrations of TQ during CD85+ T-cell activation resulted in enhanced survival of the activated T cells and sustained expression of CD62L. These effects coincided with enhancement in the capability of CD8+ T cells to produce the effector cytokine interferon-gamma (IFNgamma). These results suggest that TQ has a beneficial effect in conditioning T cells in vitro for adoptive T-cell therapy against cancer and infectious disease.

The anti-tumor effect of bee honey in Ehrlich ascite tumor model of mice is coincided with stimulation of the immune cells.

Honey is thought to exhibit a broad spectrum of therapeutic properties including antibacterial, antifungal, cytostatic and anti-inflammatory activity and has been used for the treatment of gastric ulcers, burns, and for storage of skin grafts. The present study investigated the antitumor effect of bee honey against Ehrlich ascites tumor in mice and the possible mode of antitumor action. Peroral administration of mice with honey (10, 100 or 1000 mg/ 100 g BW) every other day for 4 weeks before intraperitoneal inoculation with Ehrlich ascites tumor (EAT, 1 x 10(6) cells) increased the number bone marrow cells as well as peritoneal macrophages, but not peripheral blood leukocytes nor splenocytes. The phagocytic function of macrophages as well as the T- and B-cell functions were also increased. Honey pre-treatment also recovered the total lipids, total proteins, as well as liver and kidney enzyme activities in EAT-bearing mice. In vitro studies on EAT cells demonstrated inhibitory effect of honey on tumor cell proliferation, viability % of tumor cells as well as the size of solid tumor. The present results indicate that the preventive treatment with honey is considerably effective against EAT in mice both in vivo and in vitro. The antitumor activity of honey may occur through the activation of macrophages, T-cells and B-cells.

Thymosin stimulates interleukin-6 production from rat spleen cells in vitro.

Thymosin fraction 5 (TF5) is a partially purified preparation of bovine thymus that affects the differentiation and function of T-cells in vitro. Interleukin-6 (IL-6) is a pleiotropic cytokine that induces terminal maturation of B-cells and T-cell activation and differentiation. Although TF5 had previously been shown to stimulate the production of a number of lymphokines, its effects on IL-6 were not known. In this study we determined the effect of TF5 on IL-6 production from rat spleen cells in vitro. TF5 (100 micrograms/ml) stimulated IL-6 production from splenocytes (0.75-3.0 x 10(5) cells/well) in the presence of 0.008-0.2 micrograms/well of the T-cell mitogen concanavalin-A (con-A) by 10-20 fold during a 72 h incubation period. Dose-response studies demonstrated that 10 micrograms/ml of TF5 was the lowest concentration capable of enhancing IL-6 production. The ability of TF5 to stimulate IL-6 production in the presence of con-A could be demonstrated within 24 h of incubation; longer incubation periods (48-72 h) correlated with further enhancements of IL-6 production. Partial purification of the IL-6-inducing activity from TF5 resulted in three subfractions possessing activity in the presence of con-A (MB2, MB3, MB7) and one in the absence of con-A (MB2). The previously characterized thymosin peptides T alpha 1 and T beta 4 had no effect on IL-6 production in the absence or presence of mitogen. This study reports a new biological activity for TF5 and suggests that a novel constituent of TF5 may enhance the production of IL-6 from spleen cells.