Context
We have reported previously that DAB389IL-2 recombinant fusion toxin targets IL-2R bearing CD4+ cells, and suppresses demyelinating disease in acute (A) - and chronic (C) - experimental autoimmune encephalomyelitis (EAE) animal models of multiple sclerosis.
Objectives
The present study was undertaken to investigate the effect of DAB389IL-2 treatment on various cytokine-secreting cell populations in A-EAE and C-EAE mice.
Materials and methods
The effects of DAB389IL-2 at doses of 200-, 800-, or 1600 kU administered i.v. on days 11–13 and 15 on the clinical score and cytokine-secreting cell populations were examined using flow cytometry.
Results
C-EAE mice treated with 1600 kU DAB389IL-2, but not A-EAE mice treated with 800 kU had significantly reduced disease. The CD3+CD25+ sub-population in spleens and spinal cords of A-EAE mice treated with 800 kU DAB389IL-2 was increased, whereas in C-EAE mice treated with 1600 kU this population was decreased. DAB389IL-2 treatment reduced CD3+CD4+, CD3+CD8+, CD4+CD8+, CD3+IL-2+, CD3+IFN-γ+ and CD3+TNF-α+ T cell subpopulations in the spinal cord in A-EAE, and C-EAE mice on day 16. CD11b+ macrophages that were IL-2-, IFN-γ-, and TNF-α-positive were reduced in A-EAE mice. DAB389IL-2 treatment reduced CD19+ B-cells positive for IL-2 or CD11b+ in the spinal cord in acute and chronic disease. DAB389IL-2 treatment also reduced lymph node CD3+CD8+, CD4+CD8+, CD3+CD25+ populations on day 16, and lymph node CD3+IL-10+ and peripheral blood CD3+CD25+ populations on day 24.
Discussion and conclusions
Our study demonstrates that DAB389IL-2 fusion toxin suppresses EAE in a dose-dependent manner, and alters inflammatory cell sub-populations during disease development.