Experimental allergic encephalomyelitis in suckling Lewis rats. Comparison with the disease in adult animals

M. C. Dal Canto, R. S. Fujinami, P. Y. Paterson

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Experimental allergic encephalomyelitis (EAE) was induced in 10-day-old Lewis rats. Clinical and morphologic differences with the corresponding disease in adult animals were studied by light and electron microscopy. Four different neuroantigen adjuvant emulsions were used: guinea pig spinal cord, guinea pig myelin basic protein, rat spinal cord, and rat myelin basic protein. Guinea pig spinal cord producd the most severe disease in suckling rats; guinea pig myelin basic protein and rat spinal cord produced mild disease; and rat myelin basic protein was not pathogenic. Adult rats responded to the four different inocula with diseases of similar intensity although with slightly different lengths of incubation time. Whereas adult rats consistently showed much more severe gray than white matter involvment, suckling rats displayed very severe white matter disease especially after guinea pig spinal cord sensitization. The white matter lesions in suckling animals were characterized by abundant fibrin and edema fluid deposition. Moreover, the cellular infiltrates were richer in polymorphonuclear leukocytes and had a lesser number of lymphoid cells and histiocytes. These findings simulate pathologic features of both hyperacute EAE and neutrophilic EAE of adult rats. Similarities with hyperacute EAE suggest that the blood-brain barrier in suckling animals may be more sensitive to the various cytotoxic substances which are liberated during the inflammatory response. Similarities with the neutrophilic form of EAE would suggest immaturity of the immunocompetent lymphoid tissues in suckling rats, with resulting over-representation of the more available polymorphonuclear leukocytes in the inflammatory infiltrates. Also related to immaturity may be the stronger response of suckling rats to guinea pig spinal cord than to guinea pig myelin basic protein. The latter, being a soluble antigen, does require the presence of a mature macrophage system in order to elicit a full immunologic response.

Original languageEnglish (US)
Pages (from-to)395-405
Number of pages11
JournalLaboratory Investigation
Issue number4
StatePublished - Dec 1 1977

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Molecular Biology
  • Cell Biology


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