The Course of Experimental Allergic Encephalomyelitis in Adult Rats after Administration of Interleukin-1β at Different Periods in Early Life

Abstract

Multiple sclerosis (MS) is a chronic disease of the CNS affecting people of working age, in which myelin and the cells producing it, and also neurons, become the targets for aggressive immune cells. It has been suggested that common childhood infections in later childhood increase the risk of developing MS. We report here studies of the course of experimental allergic encephalomyelitis (EAE) in rats given interleukin-1β (IL-1β) at different stages of early postnatal ontogeny. EAE was induced in rats at age three months by single subcutaneous immunizations with homologous spinal cord homogenate in complete Freund’s adjuvant. The number of sick animals was recorded daily, as were the severity and duration of disease. EAE was found to have a more severe course after administration of IL-1β in weeks 1 and 4 of life than in rats of the corresponding control groups. The harmful or protective consequences of IL-1β administration at different periods of early postnatal ontogeny are discussed, as are the role of stress reactivity and its link with the “hygiene hypothesis.”