CD40 ligand-CD40 interaction induces chemokines in cervical carcinoma cells in synergism with IFN-gamma

Abstract

Cellular immunity plays a major role in controlling human papilloma virus infection and development of cervical carcinoma. Mononuclear cell infiltration possibly due to the action of chemokines becomes prominent in the tumor tissue. In fact, the macrophage chemoattractant protein-1, MCP-1, was detected in cervical squamous cell carcinoma in situ, whereas absent in cultured cells. From this, unknown environmental factors were postulated regulating chemokine expression in vivo. In this study, we show high CD40 expression on cervical carcinoma cells and CD40 ligand (CD40L) staining on attracted T cells in tumor tissue, suggesting a paracrine stimulation mechanism via CD40L-CD40 interactions. We therefore investigated chemokine synthesis in nonmalignant and malignant human papilloma virus-positive cell lines after CD40L exposure. Constitutive expression of MCP-1, MCP-3, RANTES, and IFN-gamma-inducible protein-10 was almost undetectable in all cell lines tested. CD40L was able to induce MCP-1 production; however, despite much higher CD40 expression in malignant cells, MCP-1 induction was significantly lower compared with nontumorigenic cells. After sensitization with IFN-gamma, another T cell-derived cytokine showing minimal effects on CD40 expression levels, CD40 ligation led to a more than 20-fold MCP-1 induction in carcinoma cell lines. An even stronger effect was observed for IFN-gamma-inducible protein-10. Our study highlights the synergism of T cell-derived mediators such as CD40L and IFN-gamma for chemokine responses in cervical carcinoma cells, helping to understand the chemokine expression patterns observed in vivo.