Abstract
We have studied the immunomodulatory effects of interferon-α2b (IFN-α2b) in rectification of the dysregulated IFN-γ-dependent chemokines and their receptor CXCR3 splice variants in head and neck squamous cell carcinoma–peripheral blood mononuclear cells (HNSCC-PBMC). CXCR3 expression was upregulated in HNSCC-PBMC, with the demonstration of poor chemotactic function. CXCR3 upregulation possibly represents the increased synthesis of CXCR3B splice variant, without significant change in CXCR3A. Upregulated expression of CXCR3B was downregulated following in vitro IFN-α2b treatment of HNSCC-PBMC. Upregulation of CXCR3A+B by IFN-α2b with downregulation of the CXCR3B indirectly suggests that the upregulation of the CXCR3A splice variant induces cellular migration. On the other hand, the stimulation of PBMC with IFN-α2b maintains physiological homeostasis of CXCR3 ligands, CXCL10 and CXCL9, and increases the secretion of IFN-γ. The suppressed chemotactic ability of HNSCC-PBMC could be restored either by in vitro treatment of PBMC with IFN-α2b or during the use of IFN-α2b stimulated PBMC supernatant as a chemoattractant. Chemoattraction process is guided at the level of both receptor and its ligands, as confirmed by neutralization studies. IFN-α2b possibly controls chemotaxis by regulating the interaction between CXCL10 and CXCR3A. Neutralization of IFN-γ downregulates the IFN-α2b mediated CXCL10 release, suggesting the active role of IFN-γ in the transduction of chemotactic signal for the migration of cytotoxic T/NK cells at the tumor site.