Activation of human monocyte-derived dendritic cells in vitro by Thymax, a gross thymic extract.

Background: We have recently demonstrated that Thymax, a gross thymic extract, induces an apoptotic effect against human breast cancer cells. In this study, the ability of Thymax to activate human dendritic cells (DCs) and the DC-directed T-cell response was examined in an in vitro culture model of peripheral blood mononuclear cells.

Materials And Methods: The level of costimulatory molecules (CD40, CD80, CD83, CD86) and T-cell proliferation were analyzed by flow cytometry. Cytokine secretion was measured by ELISA.

Results: Thymax activated DCs to secrete interleukin (IL)-12p40 and IL-6 cytokines and inhibited IL-10 production. Additionally, Thymax caused the up-regulation of CD80 and CD86 in DCs, leading to an increase in CD4(+) T-cells, which subsequently induced secretion of interferon-gamma (IFN-gamma).

Conclusion: Taken together, the data showed that Thymax activated DCs and, consequently, Th1 cells. Thus, Thymax is an immune-activating compound that needs to be evaluated extensively for its possible therapeutic properties.