Objective: To investigate the antitumor mechanism of interleukin-2 (IL-2) and interleukin-6 (IL-6) gene therapy.
Methods: Liposome encapsulated IL-2 DNA and IL-6 DNA were intraperitoneally (i.p.) injected into mouse lymphoma cell line (EL-4) lymphoma-bearing mice. Macrophage function (M phi) from the mice was assessed.
Results: Cytotoxicity, major histocompatibility (MHC) II expression and IL-1 and TNF secretion of the macrophages all augmented after i.p. injection of liposome encapsulated IL-2 DNA or IL-6 DNA. More efficient activation of macrophages was observed in mice treated with liposome encapsulated IL-2 DNA than IL-6 DNA. IL-2 gene therapy combined with IL-6 gene therapy showed the maximal activation of macrophages in the lymphoma-bearing mice.
Conclusion: IL-2 and IL-6 gene therapy can relieve the suppression of macrophages of the lymphoma-bearing mice, and efficiently activate the antitumor immune responses.