Expression of ICAM-1, VCAM-1, L-selectin, and leukosialin in the mouse central nervous system during the induction and remission stages of experimental allergic encephalomyelitis.

Adhesion molecules facilitate infiltration of leukocytes into the central nervous system (CNS) of mice with experimental allergic encephalomyelitis (EAE). Expression of the adhesion molecules ICAM-1 (CD54), VCAM-1 (CD106), L-selectin (CD62L), and leukosialin (CD43) was analyzed via immunocytochemistry 4-28 days after the injection of encephalitogen into EAE-susceptible SWXJ mice. Constitutive ICAM-1 expression on large-diameter CNS vessels was upregulated on post-injection days 8, 11, 14 and 18 (concurrent with de novo expression on smaller capillaries and glial cells), partially downregulated by day 23, and back to control levels by day 28. Constitutive VCAM-1 expression was upregulated by day 14 and back to control levels by day 28. Upregulation of ICAM-1 temporally coincided with the immigration of CD4+ lymphocytes and L-selectin+ leukocytes into the CNS, while downregulation coincided with their emigration. The infiltration of CD43+ leukocytes also coincided with the upregulation of vascular adhesion molecules, but CD43+ cells remained in the CNS after ICAM-1 and VCAM-1 had returned to control levels. Cellular infiltration and adhesion-molecule expression preceded EAE clinical symptoms by a minimum of 3 days, suggesting a causal role of adhesion molecules in the initiation of CNS inflammation. However, prophylactic injections of monoclonal antibodies against either ICAM-1, L-selectin, or CD43, did not ameliorate the clinical severity of EAE in this model.

Splenic norepinephrine is decreased in MRL-lpr/lpr mice.

The MRL-lpr/lpr mouse, a genetic model of the human autoimmune disease systemic lupus erythematosus, has been studied extensively to determine the etiology and the pathological course of the disease in lymphoid organs. At approximately 8 weeks of age, splenomegaly develops due to a massive increase in an abnormal population of T cells, resulting in a disruption of the normal splenic architecture. Part of the normal splenic architecture includes postganglionic noradrenergic sympathetic nerve fibers, which can exert influence on a variety of immunological functions. Noradrenergic innervation and norepinephrine content of spleens from both male and female MRL-lpr/lpr mice and MRL(-)+/+ congenic controls were examined at 6, 12, 18, and 24 weeks of age. Norepinephrine content is reduced in MRL-lpr/lpr male and female mice prior to the onset of observed splenomegaly and remains reduced at all ages examined. Remaining noradrenergic fibers are found in their usual compartments, but are greatly diminished compared with controls.