TABLE 1.

Characteristics of the two types of histopathologic lesions caused by murine CM

Lesion type	Disease characteristics
1	Death within 18 to 24 h of CNS signs
	Microglial and endothelial cell activation
	Production of TNF-α and IFN-γ within CNS
	Paucity of mononuclear inflammatory cells in CNS
	Widespread CNS microvascular destruction, including disruption of microvascular reticulum and conglomeration of material that reacts with HAM-56 staining
	Lesions observed in all naive C57BL/6J mice and 80% of immunized A/J mice
2	Nonlethal, associated with protection
	Reversible
	Focal mononuclear cell inflammation within brain and meninges
	Focal hemorrhage
	Minimal abnormalities visible in reticulum or with HAM-56 staining
	Lesions observed in all immunized C57BL/6J mice and 20% of immunized A/J mice