Expression of CD43 in human microglia and its downregulation in Alzheimer's disease.
CD43 (leukosialin, sialophorin) expression in brain tissue of neurologically normal and Alzheimer disease (AD) cases was studied immunohistochemically. Abundant CD43-like immunoreactivity was detected in ramified microglia of normal brain. It was also seen in residual leukocytes in capillaries and was faintly detectable on the surface of some normal appearing neurons. In AD brains, the overall expression of CD43 by microglia was markedly lower than in control brains. This was in contrast to HLA-DR which was sharply upregulated due to the activated state of the microglia. This is the first report of a microglial marker which is more highly expressed in the resting or ramified state. Such expression is consistent with theories that CD43 plays an anti-adhesional role, and that cleavage occurs during cellular activation.
Matsuo
A
A
Kinsmen Laboratory of Neurological Research, University of British Columbia, Vancouver, Canada.
Walker
D G
DG
Terai
K
K
McGeer
P L
PL
D000544:Alzheimer Disease / Q000276:immunology*; D015703:Antigens, CD; D002460:Cell Line; D015536:Down-Regulation; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D051917:Leukosialin; D017628:Microglia / Q000378:metabolism*; D012795:Sialoglycoproteins / Q000378:metabolism*
D015703:Antigens, CD; D006684:HLA-DR Antigens; D051917:Leukosialin; C465014:SPN protein, human; D012795:Sialoglycoproteins