Relapsing autoimmune demyelination: a role for vascular addressins

The expression of two vascular addressins, adhesion molecules implicated in lymphocyte traffic via high endothelial venules (HEV) within lymph node and mucosal tissues, and of an HEV differentiation antigen (Ag) has been followed immunocytochemically in the central nervous system (CNS) of SJL mice at different stages of adoptively-transferred, chronic relapsing experimental autoimmune encephalomyelitis (EAE). Monoclonal antibody (mAb), MECA-325, which defines an HEV cell differentiation Ag generally associated with vessels involved in lymphocyte traffic, gave consistently high levels of expression on and around blood vessels within spinal cord lesions during periods of inflammation (acute onset and relapses). Two mAbs, MECA-89 and MECA-367, both recognizing the same mucosal adressin showed an affinity for endothelial cells and some astrocytes but only in lesions from animals displaying relapses. MECA-79, an mAb against a peripheral lymph node vascular addressin, showed no CNS staining whatsoever. All four antibodies gave uniformly positive staining on control lymphoid tissue. Since some stages of EAE appeared to be associated with the expression of different addressins, the possibility of separate roles for these distinct molecules should be considered.