Increased lycopene intake might have cardiovascular benefits, potentially through anti-inflammatory mechanisms. We recently showed that lycopene can influence lymphocyte activity by modulating processes involved in early cellular activation. T lymphocytes comprise different subsets, T cytotoxic, T helper 1 (Th1), T helper 2 (Th2) and T regulatory cells (Treg). We aimed to determine whether lycopene could specifically modulate T-cell subsets function and activity.
Peripheral blood mononuclear cells from 11 healthy adults were cultured for 18hr to 60h in the presence of lycopene-enriched liposomes (0-1.18μg lycopene/ml) with or without mitogens. The secretion of cytokines representative of Th1,Th2 and Treg activities were measured by ELISA (IL-2, IL-1β, IL-10, IFN-γ and TGF-β) or cytometric bead array (IL-4, IL-10, IL17 and IFN-γ). The population profile of Tc (CD3+/CD8+), Th (CD3+/CD4+), Treg (CD4+/CD25+), and the Treg subsets nTreg (CD4+/CD25+/FoxP3+) and iTreg (CD4+/CD25+/IL-10+) was determined by flow cytometry.
After 18h incubation, IL-2 concentration in the medium was significantly reduced (-29%, p=0.001) in the presence of lycopene (1.18μg/mL). Similar effects were observed after 36h and 60h culture for IFN-γ (-23%, p=0.015), Il-10 (-30%, p=0.023), IL-17 (-30%, p=0.019) but not IL-4 or TGF-β. The proportion of Treg cell was also significantly increased by 36% (p=0.001) in the presence of lycopene (1.18μg/mL) compared with non-treated activated cells. Furthermore, the proportions of iTreg cells were significantly increased by after incubation with lycopene while the proportion of nTreg cells decreased (-20.5 %, p=0.049).
We conclude that increased lycopene intake may be beneficial against atherogenesis by modulating T lymphocyte function, particularly in relation toTh1 and Treg.
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