Enhanced production of IL-2 from anti-CD3 antibody-stimulated mouse spleen cells by caffeic acid phenethyl ester, a major component of Chinese propolis.

OBJECTIVES: We evaluated the immune-modulatory effects of Chinese propolis (CP) and its major constituent, caffeic acid phenethyl ester (CAPE), on the cytokine production of anti-CD3 antibody-stimulated mouse spleen cells. METHODS: Mouse spleen cells stimulated by anti-CD3 monoclonal antibody were co-cultured with CP, CAPE, and HC030031, a specific antagonist of the TRPA1 Ca2+-permeable cation channel. Cytokine production was assayed by enzyme-linked immunosorbent assay. Interleukin (IL)-2 mRNA expression was examined by reverse transcription-quantitative polymerase chain reaction. RESULTS: In stimulated spleen cells treated with 1/16,000 CP diluent, IL-2 production was markedly enhanced, while IL-4 and IL-10 productions were not significantly affected. In contrast, interferon (IFN)-γ, IL-6, and IL-17 productions were markedly reduced. These effects of CP were reproduced by the CAPE treatment. A time-course observation demonstrated that, compared to control cells, IL-2 mRNA expression and production were significantly enhanced in the spleen cells stimulated by CAPE; however, IL-2 production was markedly delayed compared to that in the untreated control cells. The enhancement of IL-2 production by CAPE was scarcely alleviated by the addition of HC030031. These effects of CAPE upon IL-2 mRNA production were abolished in spleen cells without anti-CD3 antibody stimulation. CONCLUSIONS: CAPE is an important regulator of CP for cytokine regulation in anti-CD3 antibody-stimulated spleen cells. The agent specifically reduced IFN-γ, IL-6, and IL-17 and slightly enhanced Th2 cytokine production while significantly enhancing IL-2 production at the transcriptional level.

Augmented secretion of IL-1α from mouse oral squamous cell carcinoma (OSCC) vcells caused by serum deprivation and hypoxia promotes immune suppressive activity of mesenchymal stromal cells.

OBJECTIVES: We have previously reported that mouse oral squamous carcinoma (OSCC), Sq-1979-1, produces interleukin (IL)-1α, which specifically enhances the immunosuppressive activity of co-cultured mesenchymal stromal 10T1/2 cells. This study assessed the conditions promoting the production of IL-1α in Sq-1979-1 cells, which could further enhance the immunosuppressive function of 10T1/2 cells, and evaluated its expression in OSCC tissues. METHODS: The expression of IL-1α was examined by RT-PCR, western blotting, and enzyme-linked immune sorbent assay (ELISA). The interferon (IFN)- γ-producing capability of anti-CD3 antibody-stimulated mouse spleen cells co-cultured with 10T1/2 cells and conditioned medium (CM) from Sq-1979-1 cells was examined by ELISA. The function of IL-1α was examined using an anti-IL1α antibody. Immunohistochemical analysis of the OSCC tissues was performed. RESULTS: The production of IL-1α from Sq-1979-1 cells was synergistically enhanced in lower serum (0.5% or 1.0% FBS) at the transcriptional level, and under hypoxia (1.0% oxygen) at the release level compared to that in the control medium supplemented with 10% FBS under normoxia. The IFN-γ-producing capability of stimulated spleen cells co-cultured with 10T1/2 cells was significantly reduced in the CMs prepared with the lower serum or under hypoxia. These functions of CMs were completely abolished by the anti-IL-1α antibody. The expression of IL-1α in OSCC tissues was prominent in the midst of a carcinomatous cellular lesion or a nearby necrotic lesion, where a supply deficiency could occur. CONCLUSION: s: IL-1α production by Sq-1979-1 cells was synergistically augmented under low serum and hypoxic conditions, which could promote the immunosuppressive activity of mesenchymal cells.