Prevention of murine experimental autoimmune encephalomyelitis by in vivo expression of a novel recombinant immunotoxin DT390-RANTES

Abstract

Experimental autoimmune encephalomyelitis (EAE) is a T-cell-mediated autoimmune disease. Chemokine receptor CCR5 has been shown to be essential for the T-cell recruitment to the inflammatory site in EAE. In this study, we assumed that an immunotoxin directed at CCR5 + cells would be able to reduce the disease activity of EAE. A recombinant immunotoxin, DT390-RANTES-SRa, was constructed in an eukaryotic cell expression plasmid consisting of regulated on activation normal T cells expressed and secreted (RANTES) as the targeting moiety and DT390 as the toxic moiety. DT390-RANTES was expressed in vitro and was highly toxic to activated mouse T cells with the inhibitory concentration 50 at 0.18 ng/ml. To evaluate whether DT390-RANTES was effective in preventing EAE, C57BL/6 mice were immunized with myelin basic protein, emulsified with complete Freund's adjuvant and were treated by injecting cationic liposome-embedded plasmid DNA into the muscle of hind limbs. Mice treated with DT390-RANTES-SRa developed a much milder EAE compared to mice treated with phosphate-buffered saline or the empty plasmid DNA. Much less CCR5 + -infiltrating cells were found in the central nervous system in DT390-RANTES-SRa-treated mice than in the control mice. This study indicates that recombinant immunotoxin can be expressed in vivo, and targeting CCR5 can attenuate the disease activity of EAE in mice.

In vivo administration of plasmid DNA encoding recombinant immunotoxin DT390-IP-10 attenuates experimental autoimmune encephalomyelitis

“…Considering the redundancy of chemokine and the receptor systems, it is not surprising that CXCR3 expression on autoimmune T cells is not essential for EAE induction [41]. Chemokine receptors CCR5 and CCR2 have also been shown to be essential in murine EAE, and treatment using these receptors as target molecules for depletion of autoimmune T cells seems to be effective in prevention of EAE in mice [42,43].…”

Therapeutic targets and recent advances in protein immunotoxins

“…The IT DT390-IP-10-Sra, containing interferon gamma-inducible protein 10 (IP-10) to target CXCR3 could effectively reduce the infiltrating CXCR3+ cells in experimental autoimmune encephalomyelitis (EAE) [36]. Another target moiety, the 'Regulated on Activation Normal T cells Expressed and Secreted' (RANTES) with DT390 has been used to target the chemokine receptor CCR5 [37]. Depletion of CCR5+ T cells in a similar strategy using PEA is also implicated in the therapy of other inflammatory diseases like renal diseases, multiple sclerosis and HIV [38].…”

Gene therapy of multiple sclerosis

“…Mice treated with DT390-RANTES-Srα develop a milder EAE with less CCR5 + -infiltrating cells in the CNS as compared to control mice [38]. Interleukin-18 (IL-18), an antigen-presenting cells (APCs)-derived protein, works together with IL-12 to induce cell-mediated immunity [39].…”