Suppressive effect of mesenchymal stromal cells on interferon-γ-producing capability of spleen cells was specifically enhanced through humoral mediator(s) from mouse oral squamous cell carcinoma Sq-1979 Cells In Vitro

Aim: The aim of this study was to compare the immunomodulatory effects in the tumor milieu of mouse oral squamous cell carcinoma (OSCC) cells harboring primary and advanced phenotypes. We established an in vitro co-culture system using mouse OSCC cells, spleen cells, and mesenchymal stromal cells. Methods: Sq-1979 is an OSCC cell line derived from C3H mice; 233-11 cells were established from a primary Sq-1979 tumor; L3–5, L5–11, and L6–8 cells were established from lymph node-metastasized Sq-1979 cells. 10T1/2 is a fibroblast line derived from C3H mice. The OSCC cells were co-cultured with anti-CD3 antibody-stimulated mouse spleen cells in the presence or absence of 10T1/2 cells, and the producing capability of interferon (IFN)-γ and interleukin (IL)-10 was evaluated using enzyme-linked immunosorbent assay. Results: The production of IFN-γ by the stimulated spleen cells was specifically enhanced in the presence of co-cultured L-cells. The production of IL-10 was conversely reduced in the co-culture with all the OSCC cell lines used. The production of IFN-γ was significantly reduced in the co-culture with directly contacted 10T1/2 cells, and further reduction was observed in the presence of Sq-1979 and 233-11 cells but remained unchanged in the presence of L-cells. The reduction of IFN-γ production was also observed by the addition of conditioned medium from the Sq-1979-1 cells. Conclusion: Sq-1979 cells specifically enhanced the immune-suppressive activity of mesenchymal stromal cells through humoral factor (s).