IL-27-Mediated Activation of Natural Killer Cells and Inflammation Produced Antitumour Effects for Human Oesophageal Carcinoma Cells

Interleukin (IL)-27, composed of p28 and EBV-induced gene 3 subunits, has diverse functions in enhancing cell-mediated immunity and silencing the immunity. We examined whether forced expression of the p28-linked EBI3 gene in human oesophageal carcinoma cells (Eca109) produced antitumour effects in a T cell-defective condition. Tumour growth of Eca109 cells expressing IL-27 (Eca109 ⁄ IL-27) was retarded in nude mice compared with parental and vector DNA-transduced tumours and survival of the mice inoculated with Eca109 ⁄ IL-27 cells was prolonged. Expression of the tumour necrosis factor-a, IL-1b and IL-6 genes was up-regulated in Eca109 ⁄ IL-27 tumour specimens while the tumours remained small in size but the increased transcription was subsequently down-regulated in enlarged tumours. Spleen cells from micebearing Eca109 ⁄ IL-27 tumours produced interferon-c and showed YAC-1-targeted cytotoxic activities greater than those of mice inoculated with parental or vector DNA-transducer tumours. Numbers of DX5 + CD69 + natural killer cells in spleen of mice-bearing Eca109 ⁄ IL-27 tumours and those of CD31 + cells within Eca109 ⁄ IL-27 tumours remained the same as found in micebearing parental or vector DNA-transduced tumours. These data collectively suggest that the IL-27-mediated antitumour effects produced in a mature T cell-defective condition were attributable to enhanced interferon-c production and natural killer activities.