OBJECTIVETo evaluate the therapeutic effect of a new recombinant immunotoxin mMIP-1alpha-DT390 on experimental autoimmune encephalomyelitis (EAE).

METHODSEAE was induced in the low-sensitive strain C57BL/6 mice with intraperitoneal injection of myelin basic protein (MBP) to simulate the human disease multiple sclerosis, followed by intramuscular injection of cationic liposome carrying the plasmid DNA SRalpha-mMIP-1alpha-DT390 in the leg muscle to elicit resistance to EAE development. The mice were then examined daily for clinical signs of EAE by an observer blind to the treatment protocol. For immunohistochemistry the mice were anesthetized and perfused with sterile PBS and paraformaldehyde, and the cerebrum, cerebellum, medulla and spinal cord were removed for preparation of serial sections. The mononuclear cells (MNCs) from the EAE mouse spleens were prepared for three-color flow cytometry analysis of the surface markers with appropriate antibodies following the BD Pharmingen cytokine staining protocol.

RESULTSEAE model was successfully established by active MBP immunization in C57BL/6 mice. Administration of the immunotoxin mMIP-1alpha-DT390 significantly delayed the disease onset and lowered the mean clinical score for EAE as compared with the control mice. Immunohistochemistry demonstrated much less CCR5(+) infiltrating cells in the central nervous system in mMIP-1alpha-DT390-treated mice than in the control. The treatment also eliminated reactive T cells in the periphery blood without affecting the number of B cells.

CONCLUSIONThe immunotoxin mMIP-1alpha-DT390 can attenuate the disease activity of EAE in mice, suggesting its potential use in the treatment of other autoimmune disorders.