Determining Immune System Suppression versus CNS Protection for Pharmacological Interventions in Autoimmune Demyelination

Evonuk, Kirsten S.; Moseley, Carson E.; Doyle, Ryan E.; Weaver, Casey T.; DeSilva, Tara M.

To demonstrate if a particular therapeutic agent modulates disease pathology in the CNS after immune cell infiltration, drug interventions should be administered during the first peak in clinical disease scoring. The SJL model of EAE is advantageous for these experiments since these mice exhibit a relapsing-remitting phenotype. If a drug treatment prevents myelin-axon degeneration, an improvement in clinical scores will be observed (Figure 6 ). Pathological assessment of myelin must corroborate a reduction in myelin damage consistent with improved clinical scores. To quantitatively evaluate myelin integrity, DAB staining of myelin basic protein (MBP) is performed, followed by statistical analysis of the optical density for this staining (Figure 7) . To further substantiate that neuroinflammation is sustained or decreased by therapeutic interventions, reactive gliosis can be assessed by measuring mean fraction area for reactive gliosis as described above (Figure 3) . To corroborate that a therapeutic intervention is directly protecting the CNS without immunomodulatory effects, attenuation of immune cell infiltration into the CNS and proliferation in the spleens must be discounted. To address this, methods for brain and spinal cord assessment of immune cell infiltration and assessment of peripheral T cell proliferation and activation should be performed as described above (Figures 4 and 5) . Taken together, therapeutic agents that block cell injury in the CNS with no evidence of a reduction in CNS-infiltrating T cells or proliferation of T cells in the periphery are CNS-protective treatments. (C) The change in percentage of T cell populations between SAS-and PBS-treated EAE mice was also examined. Mean ± SEM, n = 10 for PBS treated, and n = 9 for SAS treated from two independent experiments. Two-tailed t test was used for all bar graphs. **p < 0.01. Re-print with permission from (11) . Please click here to view a larger version of this figure.