APOPTOTIC CELLS ARE PRESENT IN THE CNS THROUGHOUT ACUTE AND CHRONIC-PROGRESSIVE EAE IN THE ABSENCE OF CLINICAL RECOVERY

Experimental allergic encephalomyelitis (EAE) is an autoimmune, demyel inating disorder of the central nervous system induced in susceptible animals as a model for the human disease multiple sclerosis. Antibodie s against the leukocyte adhesion molecule alpha 4 integrin have been s hown to prevent and reverse acute and chronic EAE of the guinea pig. T he results presented in this paper implicate apoptosis as the mechanis m of reversal of EAE following treatment with anti-alpha 4 integrin an tibody. Apoptotic cells were observed in the central nervous system (C NS) throughout chronic-progressive EAE of the guinea pig in the absenc e of clinical recovery. Many of the apoptotic cells were identified as T cells using immunohistochemistry. Similarly, apoptotic cells were p resent in the CNS of animals during anti-alpha 4 integrin-mediated rec overy from acute and chronic disease. Therefore, anti-alpha 4 integrin -mediated recovery from EAE is due to the prevention of the influx of new inflammatory cells into the CNS that are required to replace those undergoing apoptosis.