Background: Multiple sclerosis and its murine model, experimental autoimmune encephalomyelitis (EAE), are chronic inflammatory demyelinating diseases of CNS. This study aimed to examine the effects of IL-27coding plasmid on disease status and certain immunological parameters in EAE-affected C57BL/6 mice.

Materials and Methods: IL-27 gene was subcloned in P240 plasmid. The recombinant P240-mIL27 and P240 plasmids were injected two times, each time 200 micrograms, to test and control EAE mice, respectively. The clinical signs of the treated mice were evaluated daily and scored according to a standard method. One week after the last injection, all mice were sacrificed. The ELISA and MTT tests were performed to evaluate the production of IL-4, IFN-γ and IL-17 from and proliferative response of splenocytes against specific antigen challenge, respectively. Furthermore, to demonstrate the immune cells infiltration, histopathological exam was performed on the brainstem of mice.

Results: The P240-mIL27 plasmid could significantly improve clinical course of EAE in the test group. Also in this group, the level of IL-4 was greater than that in the control group, while the levels of IFN-γ and IL-17 were lower than those of the control group. In MTT test, the splenocytes of the test group showed a significantly less proliferative response than the control group. Finally, less infiltration of immune cells was seen in the brainstem of EAE mice treated with P240-mIL27 plasmid.

Conclusion: IL-27 by shifting the immune responses from inflammatory Th1/Th17 towards anti-inflammatory Th2-type responses could be a suitable candidate for the treatment of inflammatory diseases such as MS.