CD4(-CELLS ARE NOT MAJOR EFFECTORS OF MOUSE HEPATITIS-VIRUS A59-INDUCED DEMYELINATING DISEASE() AND CD8(+) T)

We examined murine hepatitis virus strain A59 (MHV-A59)-induced demyel inating disease in C57BL/6 mice which had previously been thymectomize d at 25 days of age. Demyelination was observed in 51-96% of spinal co rd quadrants examined 30 or 60 days post infection (dpi), indicating t hat neither an intact thymus nor thymic infection is a prerequisite to demyelination. Depletion of CD4(+) or CD8(+) T cells at 5, 7 or 10 dp i did not influence the extent of demyelination indicating that neithe r T cell subset is a major effector of demyelination. However, these f indings do not exclude the possibility that T cells are involved in in itiating demyelinating disease very early in infection.